Search

• A new composite coating is prepared on the laser remelted surface using micro arc oxidation. • The prepared composite coating retains the laser remelting microgroove structure. • The composite coating increases the biocompatibility. This study used a combination of laser remelting (LR) and micro-arc oxidation (MAO) treatment techniques to surface-modify TC4 alloy for implant applications. The LR-MAO coatings successfully maintained the porous structure of MAO while endowing the coatings with a microgroove structure and improving the roughness of the composite coatings. The surface morphology, physicochemical, and biological properties of the LR-MAO composite coatings were systematically investigated. The results showed that LR pretreatment is an effective method to enhance the biocompatibility of the MAO implant surface. [ABSTRACT FROM AUTHOR]

• Preparation of a thin layer of tantalum coating on an alkali hot surface using magnetron sputtering. • The prepared tantalum coatings retained the hierarchical mesh porous structure of alkali heat surface. • Alkaline thermal and tantalum composite coating increases both biocompatibility and antimicrobial properties of SLA implants. In order to achieve both antibacterial and biological activity on the SLA (sandblasted large-grit acid-etched) surface, this study utilized alkali treatment and magnetron sputtering to create a layer of AT + Ta (alkali treatment and tantalum) composite coating on the SLA surface to enhance biocompatibility and antibacterial properties. The AT + Ta coating successfully maintained the hierarchical porous structure of alkali treatment while also improving antibacterial properties. The physical and chemical properties, antibacterial properties, and biocompatibility of the AT + Ta coating were systematically investigated. The results suggest that AT + Ta coating could be an effective approach for enhancing the surface properties of SLA implant. [ABSTRACT FROM AUTHOR]

• A novel multicomponent Na 2/3 Mn 0.67 Ni 0.22 Cu 0.05 Ti 0.02 Al 0.02 O 2 (NaMNCTAl) cathode was designed and prepared. • The as-synthesized NaMNCTAl exhibits both ultra-long cycle life and ultra-high rate capability. • Its reversible capacity is approximately 94.6 mAh g−1 at 1.0 C after 400 cycles. • At high rate of 10 C, it still presents a discharge capacity of 66 mAh g−1 after 900 cycles. In this work, we propose a novel material design method, and develop a multicomponent P2-type layered sodium oxide Na 2/3 Mn 0.67 Ni 0.22 Cu 0.05 Ti 0.02 Al 0.02 O 2 (NaMNCTAl). This multicomponent material can combine the advantages and functionalities of multiple different metal ions. In the designed NaMNCTAl, Cu element can provide new redox center, Ti element can enlarge interslab distance, Al element can reduce Jahn-Teller distortion. The synergy effect from such a multicomponent design can result in enhanced electrochemical kinetics and structural stability of NaMNCTAl. When used as cathode for sodium-ion batteries, the NaMNCTAl displays an unprecedented electrochemical performance of both ultra-long cycle life (87.8% capacity retention over 400 cycles at 1.0 C rate) and ultra-high rate capability (72.7 mAh g−1 at 10 C). This design strategy based on multicomponent can provide new avenues for designing advanced cathode materials with superior comprehensive performance. [ABSTRACT FROM AUTHOR]

• Micro-LSP is proposed to increase the wear resistance of AISI 5140 steel. • Micro-LSP increased the surface hardness, and decreased the friction coefficient and surface roughness. • The wear rate of specimens after Micro-LSP treatment is lower than that of LSP treatment. • Micro-LSP increased the resistance of the sample to foreign substance intrusion. AISI 5140 steel is widely used in automobile steering shafts, whereby its abrasion resistance directly affects the reliability of transmission components. This paper proposes Micro-laser shock peening (Micro-LSP) as a new laser shock peening (LSP) treatment. The surface of the AISI 5140 steel was examined after Micro-LSP, and its influence on the wear resistance was determined. Compared with LSP, Micro-LSP exhibited a better strengthening effect on the wear and surface hardness. After Micro-LSP treatment, the surface hardness of the sample was 368.7 HV 0.5 , the depth of the hardened layer was 580 μm, and the surface roughness was 1.40 μm. This improved wear resistance is attributed to the higher microhardness and formation of a surface oxide layer. [ABSTRACT FROM AUTHOR]

• A low-density and high-strength SCBD with a homogeneous structure was prepared. • The yield of SCB is related to the content of light components. • The volume shrinkage of SCB increased by 56.1 % after removing light components. • The flexural and compressive strength increased by 84.6 and 103.0 %, respectively. • SCBD has a better crystal structure due to the removal of harmful light components. A new process of removing useless volatile matter from green petroleum coke (GPC) using recoverable dichloromethane (CH 2 Cl 2) was developed to prepare self-sintering calcinated block (SCBD), which had potential application as carbon sealing materials (CSMs). Self-sintering calcinated block (SCB) was also prepared without removal unless volatile matter from GPC. Compared with SCB, SCBD had not only lower open porosity, median pore diameter and denser microstructure, but also provided superior mechanical properties, higher volume density and high yield of about 100 %. Furthermore, the flexural and compressive strength were increased by 84.57 % and 102.97 %, respectively. The correlations between the structure and properties of carbon materials were also discussed in detail. It was demonstrated that the new process studied in this work had more advantages in improving the adhesion, self-sintering, mechanical properties, and yield of the GPC than conventional direct molding process. [ABSTRACT FROM AUTHOR]

Uniform ZnO nanospheres have been successfully synthesized through a facile solvothermal process. The structure and morphology of the products were characterized by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that the products were ZnO nanospheres of 300–350 nm in diameter, which were composed of nanoparticles of ca. 5–10 nm. The size of the nanospheres can be tuned from ca. 300 nm to 1 μm by changing the concentration of the reactants. The gas sensing performance of the ZnO nanospheres with different size were investigated, which indicated that the ZnO nanospheres exhibited good gas sensitivity and selectivity towards n-butanol. In addition, the gas sensitivity of the ZnO nanospheres exhibited obvious size-dependent effect. [ABSTRACT FROM AUTHOR]

• The material used for biopsy puncture is copper alloy, which is an innovative material. • Has a magnetic susceptibility close to that of human bone tissue. • No susceptibility artifacts. • Has good corrosion resistance and mechanical properties comparable to medical materials. Combining the excellence of magnetic resonance imaging (MRI) and the perspective of exploring new materials, this paper predicts and analyzes the prospects for applying titanium bronze (Cu-2Ti) in biopsy surgical puncture under MRI conditions. Compared with the medical material TC4, Cu-2Ti is found to have specific strength and elongation and has a magnetic susceptibility close to that of human bone tissue. The results of the immersion and polarization curves of the simulated body fluid showed good corrosion resistance and a safe amount of dissolved copper ions (Cu2+). The finding that Cu-2Ti hardly produces magnetic susceptibility artifacts by different scan sequences of magnetic resonance. This provides a new value for applying orthopedic biopsy puncture needles. [ABSTRACT FROM AUTHOR]

• The yield of carbon block was about 100% by CH 2 Cl 2 to remove light components. • The compressive strength and flexural strength increased by 89.2% and 35.2%. • The advantages to remove light components were systematacially expounded. The self-sintering process provides the possibility to prepare high-performance special carbon graphite material. However, the problem of extremely low yield caused by products cracking has not been effectively solved, which greatly limits its commercialization process. This paper creatively proposes that after removing the light component volatile substances of pure green petroleum coke (GPC) by dichloromethane (CH 2 Cl 2). Then, carbon materials with a yield of about 100% was prepared by compression molding at 10 MPa and calcinating at 1050 °C for 4 h. Compared with GPC, the adhesion, self-sintering and mechanical properties of the product can also be greatly improved by this method. And its compressive and flexural strengths are increased by 89.2% and 35.2%, respectively. This exciting discovery can provide new research ideas and directions for the self-sintering process to prepare high-performance special carbon graphite material. [ABSTRACT FROM AUTHOR]

Abstract: The micro structural evolution and the mechanism of recrystallization grain growth (GG) were studied during re-aging process in the Cu–Ni–Si alloy containing finely pre-aging δ-Ni2Si precipitates using computer simulations based on a diffuse-interface phase-field kinetic model, in which the temporal evolution of the spatially dependent field variables is determined by numerically solving the time-dependent Ginzburg–Landau (TDGL) equations for the structural variables. The results show that the finely dispersed pre-aging δ-Ni2Si particles exert a strong pinning effect on the recrystallization grain boundaries (GB). Initially the GG accords with the power growth law with n between 0.3 and 0.4, followed by a gradual transition to growth stagnation. The final grain size follows a Zener type relation =1.41⁎(r / f a 0.49), with r the radius and f a the area fraction of the particles. The simulation results are compared with theoretical relations and previous simulation results. [Copyright &y& Elsevier]

Abstract: After solid solution treatment, the effects of aging processes on the microstructure and electrical conductivity of Cu–Cr–Zr–Mg lead frame alloy were investigated in order to determine the phase transformation and the time–temperature-transformation (TTT) behavior. The results show that aged at 470 °C the fine precipitation of an ordered CrCu2(Zr,Mg) phase is found in copper matrix as well as fine Cr and Cu4Zr, aged at 550 °C the phase CrCu2(Zr,Mg) is decomposed into Cu4Zr and Cr phase, aged at 600 °C the precipitates is bcc Cr only. The phase transformation kinetics equation was deduced from the Avrami empirical formula based on the linear relationship between the electrical conductivity and the volume fraction of the phase transformation. [Copyright &y& Elsevier]

Abstract: An intelligent technique of artificial neural networks combined with genetic algorithms is developed for the analysis and optimization of the correlation between heat treatment parameters and properties in Cu–Cr–Sn–Zn lead frame alloy. A supervised artificial neural network (ANN) to model the nonlinear relationship between parameters of aging treatment with respect to hardness and conductivity properties was proposed for the alloy. The ANN sub-model improved by the Levenberg–Marquardt training algorithm has good generalization performance. Genetic algorithms (GAs) are used to optimize the input parameters of aging temperature and time. The verifying experiment has shown that the theoretical optimization agrees with the experimental evidence. [Copyright &y& Elsevier]

Transparent Cr4+ doped SiO2–Al2O3–ZnO–Li2O–K2O glass ceramics were prepared by conventional melting method. X-ray diffraction analysis revealed that the Zn1.7SiO4 nanocrystals were precipitated in the glass matrix after heating treat between 625°C and 700°C for 2h. The crystallite size is about 5nm after the heat treatment was performed at 650°C. The energy levels of Cr4+-doped glass ceramics are close to the cross of 1 E and 3 T states. Broad infrared luminescence centered at 1307nm with a full width at half maximum (FWHM) of more than 246nm was observed from the sample heat treated at 650°C excited by an 808nm excitation laser diode. And the lifetime was about 1.97μs at 1307nm. The results show the transparent glass ceramics containing Cr4+-doped Zn1.7SiO4 have potential application in optical communication. [ABSTRACT FROM AUTHOR]

Abstract: A simple soft-template route was developed to synthesize magnetic FeNi alloy ordered mesoporous carbons (FeNi/OMCs). The effects of Fe(NO3)3 and Ni(NO3)2 loading amount on the structural parameters, the morphologies and magnetic properties of the samples were evaluated. The experimental results showed that with the increasing loading amount of metal nitrates, the ordering, the specific surface area and the total pore volumes of FeNi/OMCs decreased, while the average crystal sizes of FeNi alloy (17.9–26.1nm) increased. The saturation magnetization strength could be easily adjusted by varying the amount of metal nitrates. [Copyright &y& Elsevier]

Abstract: TiAlN/SiO2 nanomultilayers with different SiO2 layer thickness were synthesized by reactive magnetron sputtering. The microstructure and mechanical properties were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and nano-indentation. The results indicated that, under the template effect of B1-NaCl structural TiAlN layers, amorphous SiO2 was forced to crystallize and grew epitaxially with TiAlN layers when SiO2 layer thickness was below 0.6nm, resulting in the enhancement of hardness and elastic modulus. The maximum hardness and elastic modulus could respectively reach 37GPa and 393GPa when SiO2 layer thickness was 0.6nm. As SiO2 layer thickness further increased, SiO2 transformed back into amorphous state and broken the coherent growth of nanomultilayers, leading to the decrease of hardness and elastic modulus. [Copyright &y& Elsevier]

Abstract: A novel approach to rapid fabrication of fullerene C60 nanotubes (FNTs) has been developed using C60–pyridine colloid as a precursor. The colloid was prepared by exposing a C60–pyridine solution to visible light. Without irradiation of the visible light, growth of FNTs is not found in the freshly prepared C60–pyridine solution and the ultrasound-agitated solution. By contrast, the FNTs were easily grown in the C60–pyridine solution which was exposed to the visible light. The observation of the Tyndall effect indicated the formation of C60–pyridine colloid that is essential for synthesizing the FNTs with excellent reproducibility. The results showed that the wall of FNTs was a local face-centered cubic crystal arrangement. [Copyright &y& Elsevier]

Abstract: Nickel nanowires were prepared by a template free method combined with chemical reduction and magnetic field. The application of an external magnetic field resulted in the formation of self-aligned metallic nickel nanowires of about 50 nm in diameter. Nickel particles were prepared in the absence of a magnetic field to better illustrate the structure directing role of the magnetic field. Physical properties of the nickel nanochains were examined by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-Ray diffraction (XRD), and thermogravimetric analysis (TGA) methods. This study provides a simple method to prepare Ni nanowires in large scale which broads their practical applications. [Copyright &y& Elsevier]

Bi 2 S 3 -nanorods charged reduced graphene oxide (RGO) was prepared by an one-pot self-assembly method. The morphologies and structures of the samples were characterized by X-ray powder diffraction and transmission electron microscopy. The as-synthesized composite showed good crystallinity and one-dimensional nanostructures uniformly dispersed on the surface of nanorods with the diameter of 80–140 nm. Combining advantages of RGO and Bi 2 S 3 , the Bi 2 S 3 /RGO composite exhibited superior electrochemical performance to bare Bi 2 S 3 . The higher discharge/charge specific capacity, better rate capability and cycling stability were achieved for graphene-backboned hybrid architectures. [ABSTRACT FROM AUTHOR]

β-In 2 S 3 nanocrystals embedded in Nafion membrane (β-In 2 S 3 /Nafion) was synthesized via a facile wet chemical method. The microstructures of as-prepared β-In 2 S 3 /Nafion were characterized by means of diverse techniques. It is found that Nafion membrane can provide a stable matrix to inhibit the agglomeration of β-In 2 S 3 nanoparticles. Due to the coupling effects between β-In 2 S 3 NCs and Nafion ionomer membrane, the as-prepared β-In 2 S 3 /Nafion film exhibited excellent photocatalytic activity and stability toward rhodamine B degradation under visible light (≥420 nm). Furthermore, this β-In 2 S 3 /Nafion sample is easy to handle and recycle for catalytic purposes. [ABSTRACT FROM AUTHOR]

Abstract: Cu2ZnSnS4 (CZTS) films were successfully prepared using a co-electrodeposition-annealing route, in which metal precursor layers were deposited by a co-electrodeposition in aqueous ionic solution, followed by the sulfurization in elemental sulfur vapor ambient at 400°C for 30min using nitrogen as the protective gas. The dependence of the structural and optical properties on composition in aqueous solution is investigated. It is shown that CZTS film synthesized at Cu/(Zn+Sn)=0.71 and Zn/Sn=1 has a kesterite structure with an absorption coefficient in the order of 104 cm−1, and the band-gap can be feasible modified by changing the element ratios in solution. This indicates that co-electrodeposition-annealing method is a viable process for the growth of CZTS films for the application in photovoltaic device. [Copyright &y& Elsevier]

• A new method for preparing CNTs/Cu-Al 2 O 3 composite powders is proposed. • Internal oxidation of Cu-Al alloy powders promotes the formation of nano-copper particles. • Nano-copper particles are catalyst for CNTs growth. • The CNTs stand uniformly on the powders and well bonded to matrix. CNTs/Cu-Al 2 O 3 composite powders were successfully synthesized by in situ CVD using Cu-Al 2 O 3 composite powders obtained by internal oxidation of Cu-Al alloy powders. The multi-walled CNTs are obtained without agglomeration and stand on the surface of the composite powders. One end of the CNTs is well bound to matrix. The Cu nanoparticle was the catalyst for the growth of CNTs on the composite powders and Al 2 O 3 on the surface of the Cu-Al 2 O 3 powder plays a key role in the growth process. [ABSTRACT FROM AUTHOR]

• The loading rate of benzotriazole in mesoporous silica was up to 12.3%. • Tannic acid coated nanoparticles have a long - term release mechanism. • Corrosion current density of self-healing coating decreases. • The low-frequency impedance modulus of self-healing coating is increased. Benzotriazole (BTA) inhibitor was coated in mesoporous silica nanoparticles (MSNs) by tannic acid complex (TAC) deposition. The tannic acid complex film was used as a pH control release valve, which could sensitively feedback and control the release of BTA. MSNs-BTA@TAC was added to the organic–inorganic composite coating, a self-healing coating with pH feedback sensitivity and corrosion compensation function was prepared. The results of electrochemical impedance spectroscopy (EIS) showed that the organic/inorganic composite coating containing 2 wt% MSNs-BTA@TAC nanoparticles showed obvious self-healing effect after soaking in simulated body fluids for 20 days, and its low-frequency impedance modulus increased from 4.9 × 104 Ωcm2 to 9.2 × 105 Ωcm2. The long-term corrosion resistance and self-healing effect of the coating were verified in simulated body fluids. [ABSTRACT FROM AUTHOR]

Abstract: Monodisperse samarium-doped ceria nanocrystals have been rapidly synthesized by a microemulsion-mediated hydrothermal method with secondary light irradiation treatment. The microemulsion system consists of cetyltrimethyl ammonium bromide and n-butanol and n-octane, acting as the surfactant, cosurfactant and oil phase, respectively. The as-synthesized nano powder is characterized by well-dispersed rhombohedral particles with their size in the range of 75 to 85nm. The results demonstrate that it could effectively inhibit coarsening and agglomeration of the product nanocrystals during the phase formation process by using the light irradiation treatment instead of conventional heat treatment. [ABSTRACT FROM AUTHOR]

Abstract: Poly (vinyl alcohol)/carbon nanotube (PVA/CNT) composite was coated on the surface of polypropylene thread for toughness enhancement. Multiwall carbon nanotubes (MWNTs) were treated in acid and alkali to get water-soluble nanotubes, and then embedded into poly (vinyl alcohol) (PVA) matrix, resulting in polymer–carbon composite with homogeneous nanotube dispersion. The stress–strain measurements show that the tensile strength and toughness of the PVA/CNT coated thread increased by 117% and 560%, respectively. These results are supportive of good interfacial bonding between the carbon nanotubes (CNTs) and polymer matrix. [Copyright &y& Elsevier]