Search

The valorization of industrial byproducts is an emerging practice that aims to transform waste materials generated during production processes into valuable resources. In this work, a preliminary study was carried out on the thermal conversion of an industrial solid byproduct resulting from the pickling of metal surfaces, mainly containing iron (II) oxalate. In a fixed-bed reactor, the thermal conversion was investigated as a function of the operating temperature and overall time. The starting material and the products obtained after heat treatment were characterized in detail, using numerous qualitative and semi-quantitative techniques. The aim of this research was to determine the optimal operating conditions for the transformation of the industrial byproduct into a high-quality product. By varying the operating conditions, it was found that complete conversion of iron (II) oxalate to magnetite was achieved at high temperatures (i.e., 773 K and 873 K) after one hour of treatment. The resulting product had a low degree of crystallization, which increased slightly with an increasing reaction time at a temperature of 873 K, reaching a maximum of about 11%. The magnetite obtained can be used in the future as a starting material for chemical looping processes as a chemical/energy carrier for the production of hydrogen. [ABSTRACT FROM AUTHOR]

A new eco-friendly slurry has been developed for the chemical mechanical polishing process with a solution of malic acid, deionized water, and an oxidizing agent hydrogen peroxide (H2O2). The surface quality of Ti-6Al4V workpieces with the proposed chemical mechanical polishing slurry with optimal parameters include oxidizers (H2O2), colloidal (SiO2) slurry, and deionized water by weight 8%, 45%, and 47% respectively, the pH concentration is adjusted 4 through the malic acid content present in the slurry. Experimental results obtained with the proposed chemical mechanical polishing method show a more improved surface quality than previous studies when applying for polishing Ti-6Al-4V alloy. The developed chemical mechanical polishing method's polishing results under optimal conditions obtain an ultra-fine surface quality with Ra = 0.696 nm over a measuring area of 53×70 μm² . X-ray photoelectron (XPS) and electrochemical measurements were used to study the chemical reaction mechanisms in the proposed chemical mechanical polishing process. The chemical mechanical polishing processes for the surface of the Ti-6Al-4V alloy workpiece with the H2O2 oxidizing agent showed high suitability with the reactants formed on the surface such as Ti, V, and Al oxide. With the proposed oxidant and the established chemical mechanical polishing slurry, the feasibility and surface quality of the super smooth Ti-6Al-4V workpiece formed after polishing were demonstrated. The established chemical mechanical polishing method shows high applicability in environmental protection and Ti-6Al-4V alloy ultra-precision machining industries. [ABSTRACT FROM AUTHOR]

The current study focuses on understanding the behaviour of flare v‐groove welds on back‐to‐back connected Cold‐Formed Steel welded sections (G300) subjected to longitudinal shear. A novel welding technique called Cold Metal Transfer (CMT) welding was used for fabrication with copper‐coated steel welding wire as a filler metal (ER70S‐6). This mode of welding has the advantage of controlled material deposition compared to the spray or globular mode of welding. Lap shear tests were carried out on unlipped channels including thickness of the weld, and length of the weld. The weld geometry was observed under an optical microscope after polishing and chemical etching of the weld cross‐section, as American Iron and Steel Institute (AISI) design standard provides no specification on thickness of flare v‐groove welds for CMT welding process. In general, the lap shear specimens failed in plate tearing failure mode and brittle fracture of weld at the weld contours. Additionally, the appropriateness of AISI's shear design strength equations for flare v‐groove welds was verified and preliminary design guidelines are provided addressing the lacunae in AISI design standard. [ABSTRACT FROM AUTHOR]

The thickness of interconnect line (THK) in copper interconnect trench plays a crucial role in the performance of integrated circuit, making it an important evaluation parameter in IC manufacturing process. FA/O II as copper chelating agent, potassium citrate (CAK) as accelerator, and 1,2-benzisothiazolin-3-one (BIT) as bacteriostatic agent were added to an oxidant- and corrosion inhibitor-free alkaline slurry for chemical mechanical polishing (CMP) of the barrier layer of copper interconnect, and the effects of their mass fractions in the slurry on the removal rates of Cu and TEOS (tetraethyl orthosilicate) and THK were studied. The results showed that the removal rate ratio of TEOS to Cu influences the THK, and the THK is negatively correlated with the resistance of barrier layer. The removal rate ratio of TEOS to Cu was about 1.7 when the mass fractions of FA/O II, CAK, and BIT in the slurry were 0.8%, 1%, and 0.04%, respectively, the THK was 225 nm, and the resistance of barrier layer was 0.18 Ω, meeting the requirements of industrial production. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) has become a promising optical material for quantum photonics and nonlinear photonics during the past decade. In this work, we propose two methods to improve the 4H-SiC thin film quality for SiC integrated photonic chips. Firstly, we develop a wet-oxidation-assisted chemical mechanical polishing (CMP) process for 4H-SiC, which can significantly decrease the surface roughness from 3.67 nm to 0.15 nm, thus mitigating the light scattering loss. Secondly, we find that the thermal annealing of the 4H-SiC devices at 1300 °C can help to decrease the material absorption loss. We experimentally demonstrate that the wet-oxidation-assisted CMP and the high-temperature annealing can effectively increase the intrinsic quality factor of the 4H-SiC optical microring resonators. [ABSTRACT FROM AUTHOR]

As sapphire device performance continues to improve, greater challenges are posed to the chemical mechanical polishing (CMP) of sapphire, with its high degree of hardness and brittleness. M-plane sapphire substrates are not widely used because they are more difficult to process, despite having higher luminous efficiency than C-plane substrates. In this study, the effect of three hydroxyl carboxylates, namely potassium tartrate (PT), potassium citrate (Cit) and sodium gluconate (Gluc), as complexing agents on the CMP of M-plane sapphire was investigated to obtain a high material removal rate (MRR) and low root mean square surface roughness (Sq). First, the chemical reactivities of the three complexing agents were predicted with Material Studio (MS) software. The predicted results showed that the complexing ability of the three complexing agents was greatest for Gluc, followed by Cit, with PT having the least complexing ability. Experimental results confirmed that Gluc was the optimal complexing agent for the M-plane sapphire CMP. The mechanism of action during CMP was revealed by X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR). The results showed that the Al(OH) 4 ‒ ions produced by the sapphire were complexed by Gluc to form the soluble complex Al(OH) 4 ‒/Gluc‒. At the same time, a solid phase reaction also occurred between the M-plane sapphire, SiO 2 , and water during CMP, and Al 2 Si 2 O 7 ∙2H 2 O was generated. After polishing with the optimized slurry, the M-plane MRR was improved to 5.358 μm/h, a 50% improvement compared with the reference slurry, and the Sq decreased from 0.345 nm to 0.172 nm. These findings provide important guidance for the development of high-performance sapphire devices. [ABSTRACT FROM AUTHOR]

Zn recovery from spent pickling liquors (SPL) from hot dip galvanization was examined with modelled solutions by combining anion exchange separation and electrodeposition processes. The solution was purified to be suitable for the electrodeposition of Zn with the main goal of eliminating the iron content. The anion-exchange resin bed in a chromatographic column primarily retained Zn, while divalent Fe was removed in the loading and rinsing steps. At the end of the process, the elution of Zn was carried out by a significantly reduced Cl- ion background. In parallel with the purification process, the potentiodynamic study (1 min runs at 40 mV/s polarization speed) of Zn electrodeposition in the series of Fe concentrations was examined. During the separation process, the preliminary reduction of the iron to its divalent state was found to be of utmost importance. The separation of iron could be improved by controlling the preliminary reduction. It was found that the effect of iron concentration on the polarization curves is complex. Initially, hydrogen bubble formation causes inhibition, but at higher iron concentrations a Zn-Fe deposit is soon formed, promoting hydrogen evolution, thereby depressing polarization but also the current efficiency. The loss of the dendritic structure obtained from pure zinc solutions also characterizes the effect of mixed Fe-Zn deposition. In order to recover pure zinc at the cathode, the pre-purification of the Zn electrolyte is essential. [ABSTRACT FROM AUTHOR]

In this letter, a millimeter scale thick film rotating traveling wave ultrasonic motor based on chemical mechanical thinning and polishing process was proposed. The 30 $\mu \text{m}$ thick piezoelectric functional layer is fabricated to realize good compactness and high piezoelectric properties. The thickness and diameter of the stator are about 240 $\mu \text{m}$ and 4 mm, respectively. The vibration mode of the motor is B02 mode under the resonant frequency of 26.2 kHz. The motor can achieve stable bidirectional rotation under the excitation of four sinusoidal voltages. Moreover, when the excitation voltage is 50 $\text{V}_{\text {pp}}$ , the maximum speed can reach 766 rpm under the preload force of 686 $\mu \text{N}$. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical–mechanical polishing (CMP) is widely adopted as a key bridge between fine rotation grinding and ion beam figuring in super-smooth monocrystalline silicon mirror manufacturing. However, controlling mid- to short-spatial-period errors during CMP is a challenge owing to the complex chemical–mechanical material removal process during surface morphology formation. In this study, the nature of chemical and mechanical material removal during CMP is theoretically studied based on a three-system elastic–plastic model and wet chemical etching behavior. The effect of the applied load, material properties, abrasive size distribution, and chemical reaction rate on the polishing surface morphology is evaluated. A microscale material removal model is established to numerically predict the silicon surface morphology and to explain the surface roughness evolution and the source of nanoscale intrinsic polishing scratches. The simulated surface morphology is consistent with the experimental results obtained by using the same polishing parameters tested by employing profilometry and atomic force microscopy. The PSD curve for both simulated surface and experimental results by profilometry and atomic force microscopy follows linear relation with double-logarithmic coordinates. This model can be used to adjust the polishing parameters for surface quality optimization, which facilitates CMP manufacturing. [ABSTRACT FROM AUTHOR]

Sichuan pickle is one of popular traditional fermented foods in China. However, the contamination of heavy metals in Sichuan pickle, particularly home‐made Sichuan pickle and aged pickle brine, is little known. Therefore, the content of trace (Cr, Cu, and Zn) and toxic elements (As, Pb, and Cd) in Sichuan industrial pickle (SIP), Sichuan home‐made pickle (SHP), and aged pickle brine collected from local markets and families in Sichuan province, respectively, was detected by inductively coupled plasma–tandem mass spectrometry (ICP‐MS/MS) and the health risk was assessed by target hazard quotients including target hazard quotient (THQ) and total target hazard quotient (TTHQ). Consequently, the mean concentrations of Cr, Cu, Zn, As, Pb, and Cd were 0.122, 0.540, 2.516, 0.023, 0.015, and 0.106 mg/kg in SIP and 0.071, 0.364, 2.698, 0.014, 0.015, and 0.289 mg/kg in SHP, respectively, lower than the maximum allowable concentrations set by Chinese regulations, except for Cr and Cd in few samples. Principal component analysis of the heavy metal content could obviously distinguish between SIP and SHP. The content of As, Pb, and Cd in leaf pickles was significantly higher than that in pickles fermented with other types of vegetables. A significant enrichment of heavy metals in aged pickle brine over 10 years was observed, but pickle jars had no significant effect on heavy metal content in aged pickle brine. The intake of heavy metals through daily consumption of SIP and SHP was at a safe level, whereas the TTHQ of leaf pickle was 1.006, indicating a potential health risk. In conclusion, this study provided fundamental data for food safety assurance of Sichuan pickle. Practical Application: Sichuan pickle is one of popular traditional fermented foods in China. In the present study, we investigated the contamination of heavy metals in Sichuan pickles by detecting the content of Cr, Cu, Zn, As, Cd, and Pb in Sichuan industrial pickle, Sichuan home‐made pickle, and aged pickle brine, and estimated the health risk to local residents. This study can provide a reference for the safety risk of Sichuan industrial and home‐made pickle in terms of heavy metal contamination, and enhance the food safety in the processing, production, and consumption of Sichuan pickle in local families and pickle industry. [ABSTRACT FROM AUTHOR]

Sapphire is widely used as a new generation of optoelectronic chips. In this article, single-sided chemical mechanical polishing (SS-CMP) and double-sided chemical mechanical polishing (DS-CMP) were conducted polishing experiments on sapphire wafers. Polishing pressure, relative rotational speed, and polishing time were investigated on material removal rate (MRR), surface roughness (SR), and parallelism of sapphire wafers under the two methods. The results demonstrate both MRR and SR of DS-CMP are significantly better than SS-CMP under the same parameters. Sapphire DS-CMP can obtain a relatively stable average MRR increment of 14.016 nm/min comparing to SS-CMP and can also obtain better surface quality when subjected to greater polishing pressure. Additionally, the parallelism after SS-CMP is about 3 times that of DS-CMP under one-time processing. Finally, sapphire CMP material removal equations are established empirically and theoretically to demonstrate the exponential equation of nonlinear relationship is more suitable for the material removal of sapphire CMP, and the mean error between the theoretical and experimental results of SS-CMP and DS-CMP is within 10%, providing a quantitative and efficient solution for manufacturing sapphire wafers. [ABSTRACT FROM AUTHOR]

The heat generated during the welding of stainless steel results in the oxidation of the surface that, apart from aesthetics, adversely affects its corrosion property too. This communication reports the successful removal of heat tint generated by the gas tungsten arc welding process off a stainless steel surface in addition to an improvement in its pitting corrosion resistance by exposure to the emission of a nanosecond pulsed fiber laser. The laser cleaning experiments, conducted with six different laser pulses having different temporal shapes and duration that varied from 20 to 1020 ns, revealed that removal of the weld heat tint was possible in all conditions provided the effective laser fluence exceeded a definite threshold value. This threshold value, in turn, was found to increase with an increase in pulse duration. The laser cleaned specimens were subsequently analyzed for surface morphology, roughness, and pitting corrosion resistance. The pitting corrosion resistance of the laser-treated specimens was compared with the as-welded specimens and welded specimens with heat tint removed using conventional methods like wire brush cleaning and chemical pickling. The superior quality of tint removal, improved pitting corrosion resistance, and the ease of noncontact operation indicates the significant potential of the fiber laser-based weld tint removal method to substitute the conventional mechanical or chemical cleaning methods currently in use in the manufacturing industry. [ABSTRACT FROM AUTHOR]

Ethylenediamine with two −NH2 functional groups was used as a critical complexing agent in chemical mechanical polishing (CMP) slurries for a high carbon chromium GCr15 bearing steel (equivalent to AISI 52100). The polishing performance and corresponding mechanism of −NH2 functional groups were thoroughly investigated as a function of pH. It is revealed that, when polished with ethylenediamine and H2O2-based slurries, the material removal rate (MRR) and surface roughness Ra of GCr15 steel gradually decrease as pH increases. Compared with acidic pH of 4.0, at alkaline pH of 10.0, the surface film of GCr15 steel has much higher corrosion resistance and wear resistance, and thus the material removal caused by the pure corrosion and corrosion-enhanced wear are greatly inhibited, resulting in much lower MRR and Ra. Moreover, it is confirmed that a more protective composite film, consisting of more Fe3+ hydroxides/oxyhydroxides and complex compounds with −NH2 functional groups of ethylenediamine, can be formed at pH of 10.0. Additionally, the polishing performance of pure iron and a medium carbon 45 steel exhibits a similar trend as GCr15 steel. The findings suggest that acidic pH could be feasible for amine groups-based complexing agents to achieve efficient CMP of iron-based metals. [ABSTRACT FROM AUTHOR]

In the process of multilayer copper wiring CMP (chemical mechanical polishing), electrochemical corrosion will occur due to the contact between slurries and metal interface. Inhibitors are added to slurries to reduce the degree of corrosion reactions. In this paper, a new reagent, adenine (AD), was introduced as a corrosion inhibitor. Electrochemical experiments showed that solutions containing AD obtained a higher potential and a more stable OCP curve than solutions without AD. Potentiodynamic polarization tests showed that the corrosion current density decreased with the addition of a 0.1 wt% AD solution. In addition, an increase in AD led to an increase in corrosion potential, and the Tafel slope indicated the anodic corrosion inhibition of AD. AFM (atomic force microscopy) and SEM (scanning electron microscopy) images of the copper surface showed that the addition of AD could improve the surface morphology of copper and reduce the number of corrosion pits. Static etch tests and polishing experiments proved that AD was an effective inhibitor. The inhibitory mechanism of AD was verified through XPS (X-ray photoelectron spectroscopy) and UV–Vis spectrophotometry experiments, which showed that AD under alkaline conditions mainly depended on the adsorption of AD molecules on the surface of Cu to form an adsorption film. In addition, XPS experiments also proved that AD covered the copper surface and was easier to clean than BTA. [ABSTRACT FROM AUTHOR]

A water-based high catalytic activity magnetorheological chemical finishing fluid (HCAMRCFF) was prepared and modified to enhance the chemical action strength in magnetorheological chemical finishing (MRCF) for single-crystal SiC. The fluid consisted of ferroferric oxide (Fe3O4) and chromium (Cr), deionized water (DW), polyethylene glycol (PEG) and oleic acid, and hydrogen peroxide (H2O2) as the composite catalyst particles, base carrier liquid, surfactants, and oxidant, respectively. HCAMRCFFs with different component concentrations were used to modify via evaluating their catalytic activity. Moreover, the MRCF experiments on SiC were conducted using the prepared HCAMRCFFs. The results show that the catalytic activity increases with an increase in the oxidant concentration. Furthermore, composite catalysts and composite surfactants can significantly improve their catalytic activity. The catalytic activity also increases with an increase in the concentration of composite catalysts. In the composite catalysts, increasing the Cr concentration can significantly enhance the catalytic performance. Composite surfactants can exert the relative superiority to enhance the catalytic activity. Compared with the unmodified finishing fluid, the catalytic activity of modified HCAMRCFF increases by 65.4%; the material removal rate (MRR) of SiC increases by 72.5% up to 635.621 nmh−1, and a surface with a roughness of 0.33 nm is obtained. [ABSTRACT FROM AUTHOR]

This paper deals with a review of the inhibition activity of various reported Schiff bases on the deterioration of mild steel in hydrochloric acid and sulfuric acid media. Mild steels find wide applications in structural, automobile and petrochemical industry, where acid solutions such as hydrochloric acid, sulfuric acid are commonly being used as pickling or descaling agents. The undue deterioration of metal during pickling can be controlled by adding a suitable inhibitor to the pickling solution. Schiff bases are widely being employed in such applications. This paper highlights the influence of structure–inhibition activity relationship of Schiff base compounds on their performance as corrosion inhibitors of mild steel in acid media. The information provided finds a useful practical application for different industrial fields in the selection of best-performing inhibitors and also for the researchers involved in the development of new novel corrosion inhibitors for mild steel in acid media. [ABSTRACT FROM AUTHOR]

One of the barriers to the recycling of chrome plated acrylonitrile–butadiene–styrene (ABS) is the degradation caused by the solution containing nitric acid used in the pickling of the metal layer. In this study, defective chrome plated ABS parts were pickled in a solution composed of lactic and sulfuric acids and hydrogen peroxide, and recycled by injection molding with different proportions of virgin ABS. The influence of pickled ABS on the chemical composition, thermal and mechanical properties of the samples was evaluated. The samples were chrome plated and characterized by visual inspection and adhesion tests. A slight yellowing of the virgin ABS/pickled ABS samples was observed due to the degradation of butadiene component. The thermal and mechanical properties were similar to those of virgin ABS. After the new chrome plating, all samples were approved in the adhesion tests, demonstrating that pickled ABS can be recycled by injection molding and chrome plating. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations of nanoscratching processes were used to study the atomic-scale removal mechanism of single crystalline silicon in chemical mechanical polishing (CMP) process and particular attention was paid to the effect of scratching depth. The simulation results under a scratching depth of 1 nm showed that a thick layer of silicon material was removed by chip formation and an amorphous layer was formed on the silicon surface after nanoscratching. By contrast, the simulation results with a depth of 0.1 nm indicated that just one monoatomic layer of workpiece was removed and a well ordered crystalline surface was obtained, which is quite consistent with previous CMP experimental results. Therefore, monoatomic layer removal mechanism was presented, by which it is considered that during CMP process the material was removed by one monoatomic layer after another, and the mechanism could provide a reasonable understanding on how the high precision surface was obtained. Also, the effects of the silica particle size and scratching velocity on the removal mechanism were investigated; the wear regimes and interatomic forces between silica particle and workpiece were studied to account for the different removal mechanisms with indentation depths of 0.1 and 1 nm. [ABSTRACT FROM AUTHOR]

The work functions of CdZnTe single crystal with different surface states were measured using synchrotron radiation photoemission spectroscopy. The work function of CdZnTe after mechanical and chemical polishing is higher than that of clean and ordered surface. The damage layer deduced by Ar ion sputtering increases the work function. The Te adatoms of the CdZnTe (111)B (2×2) reconstruction form the interface dipole and increase the work function. The effects of H2O adsorption and Au evaporation on the work function of CdZnTe were investigated. The relationships among work function, surface dipole, valence band bending, ionization energy, and electron affinity of CdZnTe with different surface states were discussed. [ABSTRACT FROM AUTHOR]

• The inhibition of S235JR steel in HCl by poly(2-ethyl-2-oxazoline)(PO) is studied. • Myristyltrimethylammonium bromide (MTAB) and KI effect on PO is examined. • PO average inhibition efficiency (η) is 80 % at 1000 mg/L. • The additives synergistically enhanced the performance of PO. • PO + MTAB + KI can offer ∼ 99 % inhibition and corrosion rate of 0.09 mm/y after 72 h. Organic compounds that exhibit little or no toxicity, have high solubility properties, and are affordable are highly sought after as metal corrosion inhibitors. The key to formulating an effective and economically viable corrosion inhibitor is the identification of compounds with strong synergistic effects. The synergistic inhibition of S235JR carbon steel in 1 M HCl by poly(2-ethyl-2-oxazoline) (PO), KI, and myristyl trimethylammonium bromide (MTAB) is studied. The durability of the PO + KI + MTAB blend is examined for up to 72 h. Results reveal an average inhibition efficiency (η) of 80 % for PO at 1000 mg/L. Adding 5 mg/L KI or MTAB to 1000 mg/L PO raised η to 97 % or 94 % from EIS measurements. PO(1000 mg/L) + KI(5 mg/L) + MTAB(5 mg/L) produced ∼ 99 % inhibition and kept the corrosion rate at 0.09 mm/y for up to 72 h. Spectroscopic and computational studies reveal PO interacted with the steel surface making use of the carbonyl functional group. The DFT calculations and MD simulations confirm the favorable tendency of the PO molecule to adsorb on the metal surface and the synergistic adsorption with KI and MTAB. Furthermore, SEM and AFM results confirm the high inhibitive performance of the blend. PO + KI + MTAB blend is highly recommended for long-term acid pickling of a metal surface and acid cleaning of plants. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the effects of different bonding agents, surface roughness, and acid pickling on the bond strength and color of ultralow-fusing porcelain fused to gold alloy. Materials and Methods: Porcelain-metal specimens were made to 25 mm 3 3 mm 3 0.5 mm with a 1-mm porcelain thickness. A 3-point bending test was used to evaluate the bond strength. The color of the porcelain was measured using a dental chromameter, and the data were processed in the CIE Lab system. The color difference (DE*) was calculated for the tested groups. Results: Good bond strength and color could be achieved regardless of the use and type of bonding agent. Surface roughness and acid pickling had more effect on the bond strength than on color. Conclusion: The type of the bonding agent, surface roughness, and acid pickling influenced the bond strength but had minimal effects on the color of ultralow-fusing porcelain. This ultralow-fusing porcelain could produce a color closer to the Vita shade than the conventional low-fusing porcelain. [ABSTRACT FROM AUTHOR]

Steel pickling processes are very important for steelmaking production quality. Pickling process is based on chemical reaction of acidic pickling solution with scale impurities on steel strip surface. In sulfuric acid pickling process together with scale removal. The partial dissolving of steel surface takes place because of sulfuric acid attack takes place. Continuous sulfuric acid carbon steel pickling in existing plants is very energy and water consumptive. An innovative approach is proposed for modernization of continuous sulfuric acid pickling process performance. The proposed neural network model may be used to optimize consumption of sulfuric acid, decrease energy consumption, reduce steel losses and, respectively, reduce harmful wastes and emissions from continuous steel pickling lines. This is possible because of quick adaptation of neural network model to changing environment through fast training algorithms. The developed model identifies the temperature necessary to provide the set process rate at the current variable values of the parameters: concentration of sulfuric acid and concentration of ferrous sulfate multi-hydrates in solution and transmits the temperature value as a current task to regulator in each discrete moment of the process. The results of application of the developed neural network, included as a part of the presented process supervisor, prove its efficiency in use for pickling process operational control: steam consumption for pickling process was decreased by 8%, acid consumption for pickling process was decreased by 26%, while the process efficiency and quality remain unaffected. [ABSTRACT FROM AUTHOR]

Abstract Co-combustion of Shenmu coal and pickling sludge was carried out in a pilot scale drop-tube furnace. The effect of different pickling sludge amounts on the NO x , SO 2 , HCl, HF, PCDD/Fs and gaseous heavy metals emissions and fly ash behaviors was studied. The burnout section furnace temperature was 1250 °C, and the pickling sludge amount ranged from 0 to 20 wt%. The result indicates that the co-combustion of <20 wt% pickling sludge did not reduce the combustion efficiency. With increasing pickling sludge amount in the blended fuels, NO x and HCl emission concentrations were basically stable; however, those of SO 2 and HF increased obviously. The total TEQ of PCDD/Fs emission was basically positively correlated to the sludge amount in the blended fuels, and the gaseous heavy metals emissions also increased obviously with the addition of sludge. To meet the national standard (GB18484-2001) on heavy metals emissions, the pickling sludge amount used in co-combustion must be <10 wt%. According to national standard (GB 16889-2008), because of the high leaching concentrations of heavy metals Cr, Ni, Cu and Pb, the co-combustion fly ash needs further treatment before being landfilled disposal as common waste. Highlights • Co-combustion was performed in a pilot scale drop-tube furnace at similar combustion condition of suspension firing boilers. • Pickling sludge addition increased the emission of SO 2 and HF obviously, while NO x and HCl emission were basically stable. • The total TEQ of PCDD/Fs emission was basically positively correlated to the pickling sludge amount in the blended fuels • To meet the national standard on heavy metals emissions, the pickling sludge amount used in co-combustion must be <10 wt.%. [ABSTRACT FROM AUTHOR]

Ultra-thin wafer with high quality was obtained by a new processing technique, which combined ultrasonic wet etching, temporary bonding, and chemical and mechanical polishing (CMP). In order to obtain a warp-free thin wafer, the pristine silicon wafer was subjected to initial thinning by ultrasonic wet etching. The temporary bonding was then conducted to anchor the wafer and ensure a stress-free de-bonding of the polished ultra-thin wafer from the supporting wafer. The subsequent CMP was applied to further reduce the thickness and roughness of the wafer. Measurements showed the as-fabricated ultra-thin wafer had an average thickness of 76 ± 2 μm, an average surface roughness of 0.32 nm, and a compressive stress of 101.4 MPa. The as-fabricated ultra-thin wafer showed improved overall appearance, with no obvious breakage, deformation, or damages on the surface. [ABSTRACT FROM AUTHOR]

Abstract Selective Laser Melting (SLM) is a powder-bed-based additive manufacturing method, using a laser beam, which can be used to produce metallic scaffolds for bone regeneration. However, this process also has a few disadvantages. One of its drawbacks is the necessity of post-processing in order to improve the surface finish. Another drawback lies in the removal of unmelted powder particles from the build. In this study, the influence of chemical polishing of SLM fabricated titanium scaffolds on their mechanical strength and in vitro cellular response was investigated. Scaffolds with bimodal pore size (200 μm core and 500 μm shell) were fabricated by SLM from commercially pure titanium powder and then chemically treated in HF/HNO 3 solutions to remove unmelted powder particles. The cell viability and mechanical strength were compared between as-made and chemically-treated scaffolds. The chemical treatment was successful in the removal of unmelted powder particles from the titanium scaffold. The Young's modulus of the fabricated cellular structures was of 42.7 and 13.3 GPa for as-made and chemically-treated scaffolds respectively. These values are very similar to the Young's modulus of living human bone. Chemical treatment did not affect negatively cell proliferation and differentiation. Additionally, the chemically-treated scaffolds had a twofold increase in colonization of osteoblast cells migrating out of multicellular spheroids. Furthermore, X-ray computed microtomography confirmed that chemically-treated scaffolds met the dimensions originally set in the CAD models. Therefore, chemical-treatment can be used as a tool to cancel the discrepancies between the designed and fabricated objects, thus enabling fabrication of finer structures with regular struts and high resolution. Graphical abstract Unlabelled Image Highlights • Removal of partially molten powder particles was effective in HF/HNO 3 solutions. • Baths which were in balance between an active and passive system were favorable. • HF/HNO 3 treatments promoted the colonization of MG63 cells. • Outgrowth of MG63 cells was conducted from multicellular spheroids. [ABSTRACT FROM AUTHOR]

Graphical abstract (a) X-ray diffraction patterns of samples, TEM (a) and SEM (b) pictures inserted, (b) photocatalytic kinetic curve of mesoporous C@ZnO hollow nanospheres via surface treatment process. Highlights • Mesoporous C@ZnO hollow nanospheres were prepared by carbon sphere template. • Enhanced photocatalytic performance can be realized by suppressing charge recombination. • Pickling process reduces surface defects and improves photocatalytic performance. • Annealing reduces internal defects and improves photocatalytic performance. Abstract Mesoporous C@ZnO hollow nanospheres were prepared by carbon sphere template. The influence of defects and surface state on photocatalytic performance was studied. The photocatalytic activity of C@ZnO nanospheres without treatment is the worst, that of the sample via pickling and annealing is secondary, and the pickling sample is the best. The improved performance can be attributed to the reduction of defects, which suppress the charge recombination. This work helps us better understand the important effects of defects on photocatalytic properties, and provides us with a feasible way to improve the UV photocatalytic activity of ZnO and other metal oxide. [ABSTRACT FROM AUTHOR]

Abstract Electrogenerated Chemical Polishing (EGCP) is a stress-free polishing method which has been verified to be an effective method to obtain an ultra-flat and ultra-smooth copper (Cu) surface without defects induced by mechanical force. However, the surface roughness deterioration and removal rate decline emerged after polishing for a long time which prevents the application of EGCP in Cu ultra-precision manufacturing. In this study, apparent activation energy experiments and energy dispersive spectrometer (EDS) analysis were carried out to explore the mechanism of the Cu surface roughness deterioration and removal rate decline. With the increasing of cupric ions (Cu2+) concentration, the apparent activation energy of the Cu/Cu2+ reaction increased which inhibited the material removal rate consequently. Furthermore, it was found that Cu micro bumps were generated on the surface which was speculated to result from the disproportionation reaction of cuprous ion (Cu+) induced by high concentration of Cu2+. Based on this study, lifting the working electrode (WE) with a fixed time interval was verified to be an effective way to avoid the deterioration of surface roughness and the decline of the material removal rate. This study contributes to a further understanding of the chemical etching mechanism of Cu in EGCP. Highlights • The reason of surface quality deterioration in Cu EGCP is revealed. • Clarify the relationship between the activation energy and etching rate. • An improved method is proposed to improve the polishing performance. [ABSTRACT FROM AUTHOR]

Highlights • Chemical polishing method is present to eliminate the damage layer. • Low concentration (≤6%) HF with short etching time (≤40 s) is optimal choice. • The return loss increases without deteriorating the surface quality. Abstract The damage layer, located at the endface of the fiber-optic connector, is currently the main intrinsic parameter that ultimately limits the connector's ability to achieve the lowest reflectance at the connection point. It deteriorates the connector's return loss and insertion loss and cannot be eliminated by mechanical method. We propose a method called chemical polishing, which is low cost and easy to operate, to eliminate the damage layer. Both theoretical and experimental work have been conducted to reveal the influence mechanism of the damage layer on the return loss and insertion loss. The results show that, by etching the damage layer in a low concentration (≤6%) hydrofluoric acid solution with a short etching time (≤40 s), we can effectively eliminate the damage layer and increase return loss without deteriorating the surface quality. [ABSTRACT FROM AUTHOR]

Stainless-steel pickling sludge is a hazardous solid waste. Harmless treatment and recycling of this sludge are major research topics. Based on the sludge formation process, two typical types of stainless-steel pickling sludge were chosen and their physiochemical properties determined by chemical analysis, differential thermal analysis/thermogravimetry, and x-ray diffraction analysis. Possible approaches to recycle the sludge were suggested, and relevant problems are discussed. Based on its high water and sulfur contents, as well as the valuable metals that could be recovered from sludge, drying, roasting, and reduction tests were carried out. It was found that Fe and Cr were mainly present in oxides, Ca in Ca(OH)2 and CaF2, and sulfur in CaSO4. Natural drying was a very slow process, but forced drying at temperatures above 423 K was effective. Sulfur could be partly removed from sludge through roasting and reduction at high temperatures, with most of the sulfur being transferred to gas and slag in the reduction process; however, this treatment did not allow sludge with high sulfur content to be used as a suitable raw material in terms of sulfur level requirements. It is suggested that prepickling and pickling waste liquors should be treated to reduce output of high-sulfur sludge to promote sludge recycling. Optimized reduction conditions were identified in terms of additional carbon content (1.3 times as suggested by theoretical data) and temperature (above 1673 K) for high metal recovery. [ABSTRACT FROM AUTHOR]

It has been found that the electrically assisted (EA) forming can alleviate size effects due to the electroplastic effect. Size effects exist in the manufacture of tiny workpieces and severely affect material performances because the grain boundary hardening effect and strong anisotropy of the mechanical properties of the grains will lead to a strong variation in the forming properties of the sheet. In order to investigate the influences of current parameters and size effects on mechanical properties in EA forming, EA uniaxial tension tests with varying grain size and thickness were conducted on T2 red copper sheets. The small temperature rise shows the thermal effect is slight; the flow stress decreases with the increase in pulse frequency, pulse duty ratio and current density; the finer grains still result in higher strength and better plasticity; Moreover, the fluctuations of tensile strength, maximum uniform strain and fracture strain decrease with the increase in the ratio of thickness to grain size (N) at constant current density, which means pulsed current can weaken size effects. [ABSTRACT FROM AUTHOR]

Tertiary oxide scale consists of magnetite and hematite, and in dual-phase steel strips were observed after the exit of final rolling stand in a thin slab casting rolling (TSCR) mill. Microscopic observation confirmed that these scales cracked and spalled off from many places of surface during coiling causing a non-uniform oxide layer on the steel surface. The present work discusses the synergistic effect of such non-uniform oxide layer and run-out-table cooling water on the electrochemical behavior of the dual-phase steel. The electrochemical response was assessed with the help of dynamic and linear polarization tests considering cooling water as electrolyte. The presence of non-uniform scale produced high cathodic (scaled zone) to anodic (spalled-off zone) area ratio that eventually led to extensive pitting corrosion in the present steel. Furthermore, the pickling behavior of the steel was also studied in detail. It was observed that the steel surface, with spalled-off area of about one-tenth of total surface area, corroded preferentially 3-4 times faster at spalled-off area than that of the uniformly pickled surface. The characterization study was performed using scanning electron microscopy, confocal laser 3D scanning microscopy, x-ray diffraction and Raman spectroscopy in order to establish the reasons for pitting corrosion due to the scale spallation. [ABSTRACT FROM AUTHOR]

Polishing SiC is a difficult task due to its exceptional chemical stability and high hardness. While the strong catalytic performance resulting from the coupling effect of ultrasonic vibration and catalysis is well-known, there have been limited studies on its effectiveness for SiC chemical mechanical polishing. To address this gap, we present a novel approach that utilizes the coupling of ultrasonic vibration and catalysis for SiC polishing. The hydroxyl free radical (*OH) generated by coupling effect is analyzed using ultraviolet-visible spectrophotometry (UV–VIS) to screen for a catalyst that matches ultrasonic vibration and establish a high-performance catalytic coupling system. The use of ultrasonic vibration in SiC polishing results in a significant increase in catalytic efficiency, with a doubling effect observed. Additionally, the catalyst itself increases ultrasonic efficiency by 43.1 %, leading to a substantial improvement in material removal rate (MRR). We study the impact of the placement of the ultrasonic vibration device on MRR and evaluate the performance of the coupling system used for polishing. Also, we delved into the removal mechanism of SiC by utilizing XPS and nyquist plots. Our findings reveal a maximum MRR of 214.6 nm/h, which improves the efficiency of commercial slurry by 80.0 %. Furthermore, the proposed strategy increases the MRR of commercial slurry by more than 70 % in the time range of 0–1 h, 1–2 h, and 0–2 h. The surface roughness (Ra) measured by AFM using a scanning area of 1 × 1 µm2 at sub-angstrom scale (Ra =0.0627 nm) is achieved. This study significantly improves the polishing efficiency of commercial slurry and has great application prospects. • Coupling system of ultrasonic vibration and catalysis is used in chemical mechanical polishing. • For the first time, it has been proven that coupling of ultrasonic vibration and catalysts promotes SiC removal rate (MRR). • O 2 *- is the main factor affecting the chemical reaction of SiC, followed by holes. • The maximum MRR of commercial slurry can be increased by 82.0% by proposed strategy. [ABSTRACT FROM AUTHOR]

Combining chemical vapor deposition (CVD) with electrochemical polish (EP) operation is a promising route to producing performance-capable superconducting films for use in the fabrication of cost-effective components for superconducting radiofrequency (SRF) particle accelerators and superconducting quantum computers. The post-deposition EP process enables a critically necessary reduction in surface roughness of niobium (Nb) thin films to promote optimal superconducting surface conditions. This work investigated surface morphology, roughness, and crystal orientation of the CVD-grown and EP-polished Nb films. The CVD films were found to comprise steps and pyramidal features, resulting in undesirable large peak-to-valley distances. EP was demonstrated to significantly diminish the height of pyramids and effectively minimize the overall surface roughness. EP results showed a probable dependence on the crystal orientation. These understandings identify the EP principles tied to CVD-grown Nb films that allow further refinement of surface profiles for film-based SRF applications. • Chemical-vapor-deposited (CVD) niobium films show large steps and pyramidal features. • Electropolishing (EP) reduces large surface roughness on CVD niobium films. • EP of CVD niobium films involves both macroscale and microscale smoothing. • The film EP results suggest a probable crystal orientation dependence. • Combining EP-CVD makes film-niobium feasible for superconducting radiofrequency use. [ABSTRACT FROM AUTHOR]

High quality CdZnTe substrates with 4% ZnTe mole fraction are used for epitaxial growth of HgCdTe infrared detector layers. Molecular Beam Epitaxy (MBE) growth of HgCdTe epilayers requires high quality surface layer with sub-nanometer surface roughness values as well. We report on the development of a CdZnTe substrate surface preparation process for MBE growth of high quality HgCdTe epilayers. Surface preparation processes were performed on both commercially available CdZnTe substrates and substrates obtained from in-house grown CdZnTe boules. We developed a multi-step substrate surface processing flow to achieve sub-nanometer surface roughness, low total thickness variation (TTV), and wax or slurry residue free CdZnTe substrate surfaces. Each process step was optimized with the aim of removing the subsurface damage caused by the previous process step; so that we reduce the amount of damaged layer needed to be etched prior to epitaxy. Our developed surface preparation process can be applicable to commercially available CdZnTe substrates with high surface roughness and high TTV. This process was also optimized for as-cut CdZnTe slices. We are capable of processing typically 25 mm × 25 mm CdZnTe substrates with achievable surface roughness values (Rrms) down to below 0.5 nm. [ABSTRACT FROM AUTHOR]

In this paper, the properties of an oxide film formed on a pure iron surface after being polished with an H2O2-based acidic slurry were investigated using an atomic force microscope (AFM), Auger electron spectroscopy (AES), and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) to partly reveal the material removal mechanism of pure iron during chemical mechanical polishing (CMP). The AFM results show that, when rubbed against a cone-shaped diamond tip in vacuum, the material removal depth of the polished pure iron first slowly increases to 0.45 nm with a relatively small slope of 0.11 nm/μN as the applied load increases from 0 to 4 μN, and then rapidly increases with a large slope of 1.98 nm/μN when the applied load further increases to 10 μN. In combination with the AES and AR-XPS results, a layered oxide film with approximately 2 nm thickness (roughly estimated from the sputtering rate) is formed on the pure iron surface. Moreover, the film can be simply divided into two layers, namely, an outer layer and an inner layer. The outer layer primarily consists of FeOOH (most likely α-FeOOH) and possibly Fe2O3 with a film thickness ranging from 0.36 to 0.48 nm (close to the 0.45 nm material removal depth at the 4 μN turning point), while the inner layer primarily consists of Fe3O4. The mechanical strength of the outer layer is much higher than that of the inner layer. Moreover, the mechanical strength of the inner layer is quite close to that of the pure iron substrate. However, when a real CMP process is applied to pure iron, pure mechanical wear by silica particles generates almost no material removal due to the extremely high mechanical strength of the oxide film. This indicates that other mechanisms, such as in-situ chemical corrosion-enhanced mechanical wear, dominate the CMP process. [ABSTRACT FROM AUTHOR]

A diamond conditioner is one of the essential components in the maintenance of surface roughness of a pad during chemical mechanical polishing (CMP). In this paper, four different types of diamond conditioner were evaluated for the pad wear rate (PWR) and the material removal rate (MRR) during the pad conditioning and the wafer polishing ex situ. The experiment results revealed that the pad conditioning is strongly dependent on the diamond orientation as compared to grit size and pitch. It is observed that the PWR for “C type” conditioners is about 0.3 mm/h which is higher than that of “N type” diamond conditioner. The COF of “N type” diamond conditioner has the lowest value of ~0.56. The MRR using pad treated by “N type” diamond conditioner is approximately 3500 Å/min, which is about 1.6 times higher than that of C1-type diamond conditioner which has same diamond grit size and pitch. [ABSTRACT FROM AUTHOR]

Hot-dip galvanizing process is used worldwide to protect the steel or iron pieces from corrosion. This process is a large generator of waste, considered one of the so-called dirty industries. One of the important wastes, in terms of quantity, is zinc ash that contains a mixture of metallic zinc and zinc oxide with a total content of zinc between 70 and 90%. The aim of this study is the preparation and characterization of a series of ZnR-Al-CO3 (R = 2-4) layered double hydroxides (LDH) by using as zinc precursor the zinc chloride obtained after hydrochloric acid leaching of fine-grained zinc ash. Results presented herein clearly demonstrated that characteristics of the synthesized samples are close to those of similar materials synthesized starting from analytical grade reagents. At the same time, it was observed that impurities existent in the zinc chloride solution prepared by zinc ash leaching (Pb, Fe, Ca), are found at traces in the synthesized LDH materials; therefore, they have no significant influence on the obtained LDH structure and properties. By this approach, several important benefits may be simultaneously achieved: (1) preventing the pollution associated with hot-dip galvanizing process wastes, (2) obtaining of valuable products with minimized costs, keeping in mind that LDH have multiple utilizations at industrial scale, (3) saving energy and material costs, and (4) increase of product competitiveness with respect to the circular economy. [ABSTRACT FROM AUTHOR]

ABSTRACT: In this work, chrome‐plated acrylonitrile–butadiene–styrene (ABS) parts containing defects in the deposited metal layer were pickled up to two times in hydrochloric and nitric acid under different immersion times. The influence of pickling on the properties of ABS was evaluated by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy–attenuated total reflection (FTIR–ATR), scanning electron microscopy, atomic force microscopy, and roughness. The pickled parts were again chromed and evaluated by visual inspection and adhesion. The metallic layer was removed and a slight yellowing of the samples surface with the increase of pickling time. There were no significant changes in the thermal behavior of the material. Some of the components of ABS were removed, as evidenced by the reduction of the absorption peaks intensity in FTIR–ATR, by the increase of roughness and presence of pores on the surface. With the increase of the immersion time and the number of pickling, there was the formation of pores with larger sizes and decrease in roughness, making metal–polymer adhesion difficult. Only one pickling, under immersion time of 30 min, was adequate for the removal of the metallic layer, allowing new chrome plating. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46131. [ABSTRACT FROM AUTHOR]

Chemical mechanical polishing or planarization (CMP) is a material removal process dominated by mechanical and tribo-chemical assisted friction and wear. The choice of abrasive plays a key role in this process. In this work, the m SiO 2 /CeO 2 composite particles, consisting mesoporous silica ( m SiO 2 ) cores and CeO 2 nanoparticle coatings, were designed and introduced into oxide chemical mechanical polishing (CMP) as novel abrasives. The abrasives were further characterized in terms of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (STEM-EDX) techniques. Five different abrasive systems were tested in the oxide CMP processes, and their performances were evaluated in terms of material removal rate ( MRR ) and surface roughness. Particularly, the effects of inner cores of composite abrasives were investigated by comparing m SiO 2 /CeO 2 (meso-silica cores), s SiO 2 /CeO 2 (solid-silica cores), and PS/CeO 2 (solid-polystyrene cores). As confirmed by TEM and XPS, the m SiO 2 /CeO 2 composite particles revealed an improved structural stability with respect to PS/CeO 2 hybrids, resulting from the formation of Ce-O-Si chemical bonding between SiO 2 and CeO 2 after high-temperature calcination. Overall, the composite abrasives resulted in a decreased surface roughness and reduced mechanical damage after CMP due to the spring-like effect coming from the elastic component of the PS or the m SiO 2 cores, compared with the conventional rigid inorganic ceria abrasives or the mixed compounds ( m SiO 2 +CeO 2 ). In addition, the m SiO 2 /CeO 2 composites exhibited a comparable surface roughness (0.20 vs 0.18 nm) and topographical variation with respect to PS/CeO 2 hybrids. However, the material removal rate for the m SiO 2 /CeO 2 abrasives (64 nm/min) was about three times larger than that of the PS/CeO 2 abrasives (19 nm/min) under the same CMP conditions. The enhanced removal rate might be related to the improved crystallinity of CeO 2 particles and the increased content of Ce 3+ ions at the CeO 2 surfaces. [ABSTRACT FROM AUTHOR]

The focus of this study was to assess the feasibility of time-gated Raman spectroscopy for stainless steel pickle liquor acid quantification. Pickle liquor is used for dissolving metal surface impurities during the pickling process. The pickle liquor samples consisted mainly of 11–89 g/L HNO 3 , 20–160 g/L H 2 SO 4 , 5–57 g/L HF and stainless steel residue. Raman peaks correlating with the different acids were identified in both aqueous and pickle liquor solutions. The linearity between Raman scattering intensity and acid concentration was studied. Multivariate PLSR calibration for pickle liquor HNO 3 , H 2 SO 4 and HF quantification was also investigated. Time-gated Raman spectroscopy was found to be a promising technique for pickle liquor HNO 3 and H 2 SO 4 quantification. [ABSTRACT FROM AUTHOR]

In this paper, we present the fabrication method of asymmetric independent dual-gate FinFETs with different gate stack using sidewall spacer patterning and two-step chemical-mechanical polishing (CMP) processes. The fin width is controlled as a result of sidewall spacer patterning. The two-step CMP processes are conducted to separate two gates and to make different gate stacks for each gate, respectively. The fabricated devices can be used for multiple applications by utilizing independent two gates. First of all, the independent two gates offer the flexible threshold voltage modulation properties by applying the second gate (G2) bias with little subthreshold swing degradation. Second, the device can be utilized as a charge trap flash memory cell by trapping electrons in the charge storage layer. These results provide a possible way to fabricate asymmetric independent dual-gate FinFETs having potential as a multi-functional single device. [ABSTRACT FROM AUTHOR]

Waste printed circuit boards (WPCBs) and steel pickling waste liquor (SPWL) have received extensive attention in recent years because of its harmfulness and resource. In this work, two-step leaching process was carried out by using SPWL as the leaching agent. A series of continuously domesticated bacteria were used for bioleaching and the bacterial strain was identified as Acidithiobacillus ferrooxidans (A. ferrooxidans) by 16S rDNA gene sequence analysis. The vast majority of the metals in WPCBs were recovered by two-step leaching, such as Cu, Pb, Zn, Sn, Al, Ni. Meanwhile, a large amount of iron was removed from SPWL, which greatly reduces the burden of the subsequent treatment. Pulp density and pH were optimized to achieve maximum recovery of copper and simultaneous removal of iron in bioleaching. It was found that the optimum conditions were pulp density 60 g/L and pH 0.5–1.0. Nearly 100% of copper was recovered and 51.94% of iron was removed under optimum conditions. The kinetic experiments showed that the rate of copper leaching was controlled by external diffusion rather than internal diffusion, because the acidic environment of the leachate prevented the formation of the precipitate and maintained it in a smaller size. [ABSTRACT FROM AUTHOR]

In a typical chemical mechanical polishing (CMP) process, the type, morphology, structure, mechanical, and surface characteristics of abrasive particles play an important role in influencing the material removal process. The novel abrasive particles with special mechanical and/or tribochemical properties have been introduced into CMP processes for the improvement of surface quality and finishing efficiency. In this work, the composite particles containing solid silica ( s SiO 2 ) cores and mesoporous silica ( m SiO 2 ) shells were prepared via a developed Stöber method using cetyltrimethylammonium bromide as a structure-templating surfactant. The as-synthesized core/shell structured s SiO 2 / m SiO 2 composite particles were characterized by powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and nitrogen sorption–desorption measurements. The effect of the s SiO 2 core size of the composite particles on oxide CMP performance was evaluated in terms of surface roughness and material removal rate ( MRR ). The root-mean-square surface roughness (0.15–0.31 nm) of the polished substrates slightly increased with increasing of the s SiO 2 core size (168–353 nm) of the composites with a comparable m SiO 2 shell thickness (16–18 nm). The s SiO 2 / m SiO 2 composite particles with a relatively smaller or larger core presented a relatively high MRR for silicon oxide films. These oxide CMP results could be rationalized according to the contact area mechanism and indentation-based mechanism, incorporating the total contact area and chemical reactivity between particles and wafers, and the indentation depth of an abrasive particle onto the substrate surface. [ABSTRACT FROM AUTHOR]

In this study, a novel approach of CMP is developed using an environment-friendly slurry consisting of silica, hydrogen peroxide (H 2 O 2 ), malic acid and deionized water. This is different from the traditional polishing, in which hazardous chemicals are used for Ti alloys. The surface roughness R a of 0.68 nm is obtained over a measurement area of 70 × 53 μm 2 , which is lower than those previously reported for a Ti alloy. This is polished by the developed optimal CMP slurry. Polishing mechanism is investigated using electrochemical and X-ray photoelectron (XPS) measurements. H 2 O 2 dominates the corrosion process during CMP using the developed environment-friendly slurry. Corrosion current of H 2 O 2 is consistent with the reactants of titania, alumina and vanadia formed on the surfaces of Ti-6Al–4 V after CMP. Corrosion potential agrees well with the polished surface quality of Ti-6Al–4 V. Chemical reaction equations are proposed according to the electrochemical and XPS measurements. The developed CMP slurry sheds light on the application in environment protection for the Ti, Ti alloys and CMP industries. [ABSTRACT FROM AUTHOR]

Electrolytic manganese anode slime (EMAS) is a solid waste found in the anode chamber during the production of electrolytic manganese metal, which mainly contains high concentration of manganese and other impurities. In EMAS, γ-MnO 2 and δ-MnO 2 turned into α-MnO 2 after calcination, and the oxide can be dissolved by pickling. The results showed that the specific surface area of EMAS increased from 33.11 m 2 ·g − 1 to 93.53 m 2 ·g − 1 , and the micropore volume increased from 0.0129 cm 3 ·g − 1 to 0.0362 cm 3 ·g − 1 , as well as the specific capacity and the Open Circuit Voltage (OCV) of EMAS were 249.65 mAh·g − 1 and 1.60 V, respectively, under the condition of calcination temperature 400 °C, calcination time 1 h, sulfuric acid 1 mol·L − 1 , pickling temperature 25 °C, pickling time 0.5 h, and liquid-to-solid ratio 8:1. [ABSTRACT FROM AUTHOR]