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Analysis of scanning electron microscope (SEM) images is crucial for characterising aluminide diffusion coatings deposited via the slurry route on steels, yet challenging due to various factors like imaging artefacts, noise, and overlapping features such as resin, precipitates, cracks, and pores. This study focuses on determining the thicknesses of the coating layers Fe2Al5 and, if present, FeAl, pore characteristics, and chromium precipitate fractions after the heat treatment that forms the diffusion coating. A deep learning SEM image segmentation model utilising U-Net architecture is proposed. Ground truth data were generated using the trainable Weka segmentation plugin in ImageJ, manually refined for accuracy, and supplemented with synthetic data from Blender 3D software for data augmentation of a limited number of SEM label images. The deep learning model trained on a combination of synthetic and real SEM data achieved mean dice scores of 98.7% ± 0.2 for the Fe2Al5 layer, 82.6% ± 8.1 for pores, and 81.48% ± 3.6 for precipitates when evaluated on manually labelled SEM data. The deep learning procedure was applied to evaluate a series of SEM images of diffusion coatings obtained with three different slurry compositions. The evaluation revealed that using a slurry without a rheology modifier may lead to a thicker partial Fe2Al5 layer that is formed by inward diffusion. The relation between the outward and inward diffusion Fe2Al5 layers was not affected by the coating thickness. The thinner diffusion coating presents lower pores and chromium precipitate fractions independently of the slurry selected. [ABSTRACT FROM AUTHOR]

We aimed to determine the relationship between surface chemistry and the rheological properties of silicon anode slurries in lithium-ion batteries. To accomplish this, we investigated the use of various binders such as PAA, CMC/SBR, and chitosan as a means to control particle aggregation and improve the flowability and homogeneity of the slurry. Additionally, we utilized zeta potential analysis to examine the electrostatic stability of the silicon particles in the presence of different binders, and the results indicated that the conformations of the binders on the silicon particles can be influenced by both neutralization and the pH conditions. Furthermore, we found that the zeta potential values served as a useful metric for evaluating binder adsorption and particle dispersion in the solution. We also conducted three-interval thixotropic tests (3ITTs) to examine the structural deformation and recovery characteristics of the slurry, and the results demonstrated that these properties vary depending on the strain intervals, pH conditions, and chosen binder. Overall, this study emphasized the importance of taking into account surface chemistry, neutralization, and pH conditions when assessing the rheological properties of the slurry and coating quality for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The strengthening of recycled aggregates is a critical issue, as the low strength of recycled aggregates is the main reason that limits their widespread use. The slurry coating method can strengthen the recycled aggregates by repairing the aggregate surface, but it is hard to improve the internal strength due to the existence of pores and cracks. In this study, a new methodology considering dry mixing with fines to fill and bond the internal pores and cracks before slurry coating is proposed. Twelve strengthened samples considering different combinations of dry-mixing fines and coating solutions were prepared, and the basic physical and mechanical properties were compared, including the water-absorption rate, crushing value, and apparent density with unstrengthened aggregates. The results indicate that the proposed methodology can change the water-absorption rate significantly and improve the crushing resistance and apparent density of the recycled aggregates. A high correlation between the apparent density and the crushing value was also observed. Furthermore, the strengthening mechanism of dry mixing was also investigated by scanning electron microscopy. The micromorphology of the strengthened aggregates indicates that internal pores and cracks can be filled by dry mixing fines and then bonded together after hydration. [ABSTRACT FROM AUTHOR]

• A brand-new fiber-shaped cathode was prepared in Zinc-ion batteries. • By adjusting the ratio of the slurry, high-performance cathode based on bundled carbon fiber was prepared. • The full solid-state fiber battery provides high performance across various bending states. Aqueous zinc-ion batteries (ZIBs) have garnered remarkable attention owing to high safety, low price, environmental friendliness, and versatile adaptability. In this paper, we present the fabrication of a fiber-based ZIB using a slurry composed of ZnVOH and carbon black as the cathode material. This battery demonstrates high capacity and a robust bonding interface. Notably, the binding strength and uniformity of the slurry on the fiber surface play a pivotal role in energy-storage capabilities. Carbon black serves the dual purpose of providing a conductive medium and a viscosity adherence to the fiber surface. ZIBs containing 15 % carbon black exhibit a high capacity of 319.8 mAh g−1 at a current density of 0.5 A g−1. In addition, the fully solid-state fiber battery demonstrates superior electrochemical performance under various bending deformations coupled with optimized electrical conductivity. Importantly, its seamless integration with textiles underscores its potential for large-scale industrial production of flexible fiber-shaped ZIBs, providing a compelling solution for flexible energy storage. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) with solid-state electrolytes (SSEs) are considered as a promising next-generation energy storage technology due to their improved safety and higher energy density. Among various SSEs, halide Li3InCl6 is emerging as a promising candidate because of its high ionic conductivity, air-stability, and wide electrochemical window. Generally, most of the ASSLBs based on inorganic SSEs are assembled by mixed dry pressing, which is not easy, to achieve uniform dispersion of powder composite cathode. Here, a slurry coating method by dispersing active materials (LiNi0.8Co0.1Mn0.1O2), SSEs (Li3InCl6), binders (ethyl cellulose, polymethyl methacrylate, styrene butadiene rubber, and nitrile rubber), and conductive carbon black in toluene solvent is used to fabricate cathodes. We studied the effects of different kinds of binders and their contents on the electrochemical performance of ASSLBs. The results show that polymethyl methacrylate, ethyl cellulose, styrene butadiene rubber, and nitrile rubber binders are all suitable for preparing cathodes, and a binder content of 2 wt% can achieve the best electrochemical performance of the ASSLBs. This work proves that the intimate contact between the active material and the halide SSE in the electrode can be realized by using slurry coating method with suitable binders, thus achieving stable electrochemical performance.

Summary: The hydrogen production researches as an alternative for fossil fuels, significantly increase in recent years. To obtain pure hydrogen, researches are focused on the electrolysis of water. One of the most important parts of these studies is to develop cathode material. In this study, electrodes are prepared by rolling slurry contained copper (I) oxide (Cu2O) and nickel (II) oxide (NiO) on a graphite support material. Then, iron (Fe) is electrochemically deposited on the prepared electrode. Finally, ruthenium (Ru) is doped electrochemically. Electrochemical impedance spectroscopy, cyclic voltammetry, chronoamperometry, and linear sweep voltammetry techniques are taken for each electrode. Scanning electron microscopy (SEM) and X‐ray diffraction analyses are performed for surface characterization. SEM pictogram shows the snowflake‐like structure for the best catalyst. It is found that the best molar ratio for Cu2O‐NiO is 2:1, the best deposition times are 10 minutes and 30 seconds for Fe and Ru, respectively. [ABSTRACT FROM AUTHOR]

A two-step method combining reactive melt infiltration and slurry coating was employed to fabricate completely protected C/C composites. Microstructure and cyclic ablation behaviour of the composites were investigated. Results show that a SiC transition layer can be obtained when ceramic coating generated during the infiltration process is preserved as part of the substrate for the slurry coating process. The SiC transition layer can improve the cyclic ablation resistance of the composites. The transition layer is the thickest when the chemical composition of the mixed powder used in the slurry coating process is n(Si):n(Mo):n(Ti) = 8:1:3. Such composites have the best cyclic resistance with 0.055 mg/cm2 mass loss in each ablation cycle. [ABSTRACT FROM AUTHOR]

Air tuyeres account for 30% of all heat losses in a blast furnace. One way of lining an air tuyere from the side of the air passage is to use a heat-insulating insert. However, the temperature stresses arising in it can lead to its premature failure during operation. The following three versions for increasing the resistance of the insert without changing its geometric dimensions are considered: the use of a two-part insert, the use of a band on part of the insert, and the deposition of a slurry coating on the insert surface from the blast side. The simulation is performed in the Ansys Fluent 18.2 and Ansys Static Structural environments. The results obtained are experimentally confirmed. [ABSTRACT FROM AUTHOR]

Air tuyeres account for 30% of all heat losses in a blast furnace. One of the methods for lining a tuyere from the air passage side is to use a thermal insulation insert. However, certain defects of the insert on the working surface of the air passage along with thermal stresses generated therein may lead to its premature failure during operation. This paper discusses applying a slurry coating to the inner surface of the insert to prevent its premature cracking and improve performance. The effect of a slurry-coated thermal insulation insert on gas dynamics and heat transfer inside a blast furnace air tuyere was studied, and simulation of the above processes was performed. It was shown that applying a slurry coating to the lower portion of the thermal insulation insert is most beneficial for increasing the heat flux and raising the air-blast temperature at the tuyere outlet, while applying the coating to the entire inner surface of the insert helps improving its resistance, which has been confirmed experimentally. [ABSTRACT FROM AUTHOR]

This paper proposes to improve the durability of the heat insulating insert for the air passage of the blast furnace tuyere by applying a slurry coating to the tuyere's inner surface. In addition, the tuyere installation variant after assembling and exposing it to hydraulic tests is considered, as well as heat loss reduction by attaching refractory fabric to the tuyere nose. The slurry coating applied to the insert's inner surface has made it more durable by at least 30%. Theoretically, the insert can be made more durable when installed in the air passage after assembling the tuyere and exposing it to hydraulic tests. Studies have shown that the heat losses can be reduced by 10% on average by using refractory siliciferous fabric to ensure the heat insulation of the tuyere nose. [ABSTRACT FROM AUTHOR]

Ceramic coatings are widely used as thermal and environment barrier coatings due to their inert properties and capability to withstand high temperature. Ceramic coatings are commonly deposited by air plasma spray process and electron beam physical vapor deposition. In the present work, a cost-effective, slurry-based dip coating technique was developed to deposit mullite-based ceramic coating on the P91 steel substrate. The coating has been characterized by X-ray diffraction technique and scanning electron microscopy. Sintering of coatings was carried out in the temperature range of 900–1000 °C. Sintering time was varied between 0.5 and 1 h. Energy dispersive spectroscopy was carried out to study the distribution and diffusion of constituent elements during high-temperature sintering. Potentiodynamic polarization tests and thermo-gravimetric analysis were performed to investigate the corrosion behavior of the coating. The coating sintered at 1000 °C was found to be free from cracks and other microdefects. The corrosion rate of coating sintered at 1000 °C was found to be 26.06 mpy whereas the uncoated sample showed a higher corrosion rate of 153.7 mpy. [ABSTRACT FROM AUTHOR]

Despite its high theoretical specific capacity, silicon (Si) poses certain challenges including large volume expansion and thick SEI layer formation during the charge/discharge process. This study investigates the crucial role of interparticle interactions and particle packing densities, uncovering their significance in enhancing the coating abilities of Si anode slurries and improving the energy capacity and cycle life of lithium-ion batteries (LIBs). A microrheological model is employed to predict the rheological properties of Si anode slurries based on their packing densities. We find that a combination of Si nanoparticles (SiNPs) of varying sizes not only augments the specific capacity and mitigate volume expansion, but also promotes a uniform slurry coating on the electrode. We quantify the coating characteristics of Si anode slurries using dimensionless structural and deformation parameters, thus providing a robust foundation for future advancements in the preparation of LIB slurries. [Display omitted] • Highly packed silicon anode slurries enhance the capacity and lifespan of LIBs. • A microrheological model was used to analyze the rheological properties of slurries. • Uniform dispersion of particles provides superior slurry-electrode adhesion strength. • Optimal particle ratios achieve desirable electrochemical performance outcomes. [ABSTRACT FROM AUTHOR]

Coatings are seen a promising way to improve the corrosion resistance of relatively cheap power plant steels to enable higher steam temperatures than currently in use. In this research, 9–12% Cr steels P91 and HCM12A are coated with aluminium diffusion coating by a slurry method and exposed for 336 hours at 833 K and 883 K to atmospheres containing varying amounts of O2, H2O, HCl and SO2. Corrosion behaviour of the coated steels is compared to that of those steels in an uncoated condition. Characterization is performed by weighing, SEM + EDS and XRD. The results show that corrosion resistance of P91 and HCM12A is significantly improved by the aluminium diffusion coating at high temperatures in atmospheres containing HCl and SO2. The corrosion rate of the aluminized specimens slightly increases with increase in test temperature but remains virtually the same irrespective of the composition of the atmosphere. On the other hand, the corrosion rate of the uncoated specimens is dependent on both the atmosphere and the temperature. The steels undergo active oxidation that results in formation of non-protective, thick and layered scales in HCl containing atmospheres. SO2 addition slightly decreases the corrosion rate although it is anyway higher than that in SO2 containing atmosphere without HCl.

Open-cell nickel-based alloy foams are attractive materials for applications such as sound damping and heat exchange, especially those involving exposure to high temperature environments. This study demonstrated the potential of a developed slurry coating technique for manufacturing open-cell Inconel alloy foams, and then investigated the effect of slurry composition on the microstructure and mechanical properties of the foams. It was found that the compressive properties of the foam can be quantitatively related to its relative density using the empirical equations. The deformation behaviour of the foam is bending-dominated; and unit cell struts undergo brittle fracture after the elastic region. Increasing the slurry solid loading leads to a higher average bulk foam density and more non-uniform crush bands in the foam under compression. Compared to other fabrication processes, this slurry coating technique is able to produce open-cell Inconel foams with relatively higher strength-to-weight ratios. This study also revealed that the sound absorption capability of the foam increases when its unit cell size is reduced. [ABSTRACT FROM AUTHOR]

The influence of the superalloy composition and crystal orientation on the formation of an unconventional thermal barrier coating system (TBC) is reported. A 6 μm-thick Pt layer was first electrodeposited onto a directionally solidified (DS) CM-247LC and a single crystal (SX) PWA-1483 substrate followed by annealing. A water-based slurry containing Al microparticles was then applied and annealed to form simultaneously a ceramic top coat and a diffusion bond coat. Irrespective of the annealing treatment (Pt, slurry), thinner diffused layers were obtained with the SX than with the DS material. Dual PtAl 2 and (Ni,Pt)Al phases formed in both diffused layers but Cr segregation at the coating/substrate interface restricted further ingress of Pt and of Al into the SX superalloy compared to the DS one. This was related to the greater Cr content in the SX than in the DS material and to the absence of grain boundaries in the former. Nevertheless, a ceramic top coat composed of hollow alumina spheres formed over the thermally grown oxide and the diffused layer on both substrates. [ABSTRACT FROM AUTHOR]

The present study compares the biomass corrosion behavior of two diffusion aluminide coating obtained by slurry application, which were deposited on two low-chromium content steels, ferritic-martensitic P92 (8.7 wt% Cr) and ferritic T22 (2 wt% Cr). Their performance degradation was conducted under an oxy-fuel combustion environment for both coated and uncoated materials both under laboratory conditions and in a pilot plant burning thistle for 500 h. Exposures were carried out in the laboratory at two different temperatures, 600 °C and 650 °C, under a model atmosphere consisting of 60 % CO 2 , 30 % H 2 O, 8 % O 2 , bal.% N 2 (in vol%), 500 vppm HCl and 2 vppm SO 2. The pilot plant used a mixed fuel of 60 wt% coal and 40 wt% thistle that was burnt and the samples were exposed to a temperature range of 600–620 °C. After testing, the results revealed that the aluminide-coated materials exhibited a very high resistance under both extreme scenarios, with a variable protective character related to their Al content. On the contrary, uncoated material exhibited severe degradation, in particular T22. Microstructural and morphological studies showed up similar corrosion patterns and products on coated and uncoated materials for both testing environments. • A laboratory scale biomass corrosion testing procedure was validated by pilot plant testing using thistle. • Two slurry aluminide coatings demonstrated biomass corrosion protection of ferritic steels • Slurry with the higher Al content was the better, exhibiting little degradation after 500 h of exposure up to 650° C. [ABSTRACT FROM AUTHOR]

In this study, Cu-Mn composite catalysts were prepared by the slurry coating method using honeycomb cordierite as a support and TiO as a carrier. The influence of the relative composition of Cu, Mn on the DeNO performance was studied for different preparation processes. It was found that the catalyst prepared by adding 15 wt% Mn and 5 wt% Cu into the slurry at the same time has higher conversion than that of the catalyst only using Mn as the active component. For the composite catalyst prepared by loading Mn and Cu onto TiO followed by the complex of MnO/TiO and CuO/TiO (weight ratio of 2:1) powder, a high activity is achieved in a temperature range, which can be due to the weak interaction between Cu and Mn. The considerable denitrification of the catalyst should be attributed to the large surface area and pore volume, uniform distribution, higher activity Mn in the form of MnO and synergy of Mn, Cu and carrier. The catalyst prepared by two methods were characterized by XRD, XPS, SEM and H temperature-programmed reduction (H-TPR). H-TPR results reveal that the interaction between Cu and Mn varies with the change of the composition of two components. XPS results illustrated that the relative atomic percentage values of n(Mn)/n(Mn) and n(Mn)/n(Mn) were significantly high for the catalyst with better catalytic performance and the MnO is the dominant phase with respect to the MnO and MnO phase in all catalysts. Meanwhile, we can draw the conclusion that the MnCu/ZTC catalyst by the mixed loading way is superior to TMnCu/CC through the order loading method by XPS and NH-SCR test. [ABSTRACT FROM AUTHOR]

A new, cast austenitic stainless steel, CF8C-Plus (CF8C-P), has been developed for a wide range of high temperature applications, including diesel exhaust components, turbine casings and turbocharger housings. CF8C-P offers significant improvements in creep rupture life and creep rupture strength over standard CF8C steel. However, at higher temperatures and in aggressive environments such as those containing significant water vapor, an oxidation-resistant protective coating will be necessary to extend service life. The oxidation behavior of alloys CF8C and CF8C-P with various aluminide coatings were compared at 800 °C in air plus 10 vol% water vapor. Due to their affordability, slurry aluminides were the primary coating system of interest, although chemical vapor deposition and pack cementation coatings were also compared. Additionally, a preliminary study of the low-cycle fatigue (LCF) behavior of aluminized CF8C-P was conducted at 800 °C. Each type of coating provided substantial improvements in oxidation behavior, with simple slurry aluminides exhibiting very good oxidation resistance after 3,000 h testing in water vapor. Preliminary LCF results indicated that thicker aluminide coatings degraded high temperature fatigue properties of CF8C-P, whereas thinner coatings did not. Results suggest that appropriately designed slurry aluminide coatings are a viable option for economical, long-term oxidation protection of austenitic stainless steels in water vapor. [ABSTRACT FROM AUTHOR]

Carbon-carbon composite (C/C) materials are prone to severe oxidation and volatilization problems. To address these issues, mullite (3AlO·2SiO)/silicon carbide (SiC) coatings were deposited on C/C composite substrates characterized into high and low densities. The coatings were applied by a two-step approach: pack cementation and silica sol based slurry coating processes. The relationship between the microstructure of 3AlO·2SiO/SiC coatings and C/C substrates during isothermal oxidation cycle at 1 500 °C was investigated using X-ray diffractometer (XRD) and scanning electron microscope (SEM) mounted with energy dispersive spectrometer (EDS). The results indicate that the density of the substrates has a marked effect on the coatings. Dense, thick and well-bonded coatings are obtained in the high density substrate. After 106 h of isothermal oxidation, the high density substrate with 3AlO·2SiO/SiC coating offers effective protection as compared to low density substrate suffering recession. [ABSTRACT FROM AUTHOR]

In this paper, oxidation behavior of 9-12% Cr steels P91 and HCM12A is studied in air and in a mixture of air and water vapor. Comparison is made between these steels in uncoated condition and coated with aluminum diffusion coating by a slurry method. Oxidation tests were carried out at 550, 600, and 650 °C for a discontinued duration of 1000 h; every 250 h the specimens were slowly cooled to room temperature and weighed. SEM + EDS and XRD characterization were performed after 500 and 1000 h. The results showed that oxidation rate of uncoated P91 and HCM12A was significantly higher in the mixture of air and water vapor than in air. Oxidation resistance of the studied materials improved substantially when they were aluminized. [ABSTRACT FROM AUTHOR]

Abstract: Zinc oxide (ZnO) is a potential pigment material for paper coating to impart brightness and better printing properties. Nano-ZnO, due to its extremely small size, gives paper coating pigment a high covering power apart from anti-fungal and UV-protecting properties. In this work, zinc oxide–soluble starch nanocomposites (nano-ZnO) was prepared by a simple and novel wet chemical method using zinc nitrate and sodium hydroxide as precursors and soluble starch as stabilizing agent. Primary particle size distribution was extracted from small angle X-ray scattering (SAXS) measurements by the hard sphere model and calculated to have an average size of 4.1nm. This nano-ZnO was coated on the surface of base paper (59 GSM) in a laboratory paper coater and their properties were studied. The brightness, whiteness, paper smoothness, print density, print uniformity, picking velocity and oil absorbency of nano-ZnO coated paper showed significant improvement than that of bulk-ZnO coated paper. In addition, the nano-ZnO coated paper showed excellent anti-fungal and UV-protecting properties that are much essential to enhance the life of a paper. [ABSTRACT FROM AUTHOR]

Abstract: CdSe x Te1−x films were deposited by the slurry coating technique using CdSe x Te1−x powders synthesized in the laboratory. X-ray diffraction studies indicated the formation of a hexagonal phase. From EDAX compositional analysis, the individual concentrations of Se and Te in the films were estimated. Analysis of the optical data indicate the band gap to vary from 1.44 to 1.68eV as the value of ‘x’ changes from 0 to 1. XPS analysis was also carried out on the films. The films were used as photoanodes in polysulphide electrolyte and it was observed that the films with composition CdSe0.6Te0.4 exhibited the maximum photoactivity. The Mott–Schottky plot indicated an n-type behaviour. Spectral response measurements were made and the electrodes exhibited a quantum efficiency of 0.6. [Copyright &y& Elsevier]

Abstract: Aqueous slurries of commercial preparations of Trichoderma harzianum Rifai strain KRL-AG2 G41 (Th), T. virens Strain G-41 (Tv), or their combination (ThTv, at half rates each of the single application rate) were applied to ‘Marktetmore 76’ cucumber seeds (Cucumis sativus L.) that were non-primed or primed for 3 days at 25°C either osmotically (−2.5MPa from 0.337 molal Ca(NO3)2) or osmomatrically (−1.0MPa from 0.135 molal Ca(NO3)2 plus −1.5MPa from 50% water in exfoliated grade 5 vermiculite). Slurries were applied to seeds (1mg per seed) either before or after priming. Seeds were sown in soilless, peat-based media with or without inoculation with Pythium aphanidermatum (Pa). Protection against damping-off caused by high pressures of Pa (16% emergence in non-coated, non-primed seeds) was increased by slurry coating Th on non-primed (76.4% emergence) or on osmotically primed seeds, with coating either before or after priming having no effect on efficacy (average 62.6% emergence). Slurry coating Th on osmomatrically primed seeds failed to increase final emergence percentage (FEP). Colony forming units per three seeds (CFU, all 103) was 2.8 for non-primed seeds, and 3.2 and 2.6, respectively, when osmotically and osmomatrically primed seeds were coated after priming. In a second study with lower disease pressure (58.1 FEP from non-coated, non-primed seeds), slurry coating of non-primed or osmotically primed seeds with Th, Tv or ThTv reduced percentage damping-off and increased FEP. The combination coating eliminated damping-off only in non-primed seeds, and tended to reduce percentage damping-off in osmotically or osmomatrically primed seeds compared to coating with Th or Tv alone. In a third study using only non-primed seeds, slurry coatings with mefenoxam fungicide, Th, Tv, or ThTv decreased total damping-off to 2.6%, 7.4%, 2.0%, and 0%, respectively, from the 30.1% occurring in non-coated seeds. Th, Tv or ThTv applied to growth media at the same rate as the seed coating (1mg per seed) were generally as effective as the seed coatings, and only the ThTv growth medium application eliminated damping-off. A fourth experiment revealed that Th, Tv or ThTv remained viable on non-primed seeds for up to 4 weeks (the longest storage duration) at 21 or 4°C, but 21°C storage resulted in faster seed germination by week 3 and higher CFU per three seeds by week 4. In summary, coating of non-primed seeds with Th, Tv or ThTv was more effective than coating primed seeds in reducing percentage damping-off. While priming treatments generally led to faster seedling emergence and greater seedling shoot fresh weight than was achieved with non-primed seeds, only for non-primed seeds was damping-off eliminated by the ThTv seed coating or growth medium application. [Copyright &y& Elsevier]

Advances in the technology of micro-structured catalytic reactors depend crucially on the catalyst layer development. A detailed investigation on the influence of the different variables on the coating quality has lead to a procedure to coat commercial catalysts inside stainless steel microchannels with good adhesion and no loss of catalytic activity. A commercially available catalyst sample is directly slurry-coated inside the microchannels. These-structured catalysts are tested for the water–gas shift reaction and compared to powder samples that underwent the same procedure. Adhesion of an alumina coating depends on both the initial particle size and the degree of macro-porosity. The latter is influenced by the nature of the binder. In the case of the commercial catalyst the particle size was difficult to control as milling was found to deteriorate its activity. Binders that can form metal complexes should be avoided in order to prevent redispersion of the active phase. [Copyright &y& Elsevier]

Abstract: Preparation conditions to obtain a dense electrolyte layer on a micro-tubular electrode support were investigated using wet coating and subsequent co-firing techniques. An anode-supported micro-tubular SOFC with 1.5mm diameter was successfully fabricated by careful control of the co-sintering process of electrolyte/anode support laminates. The densification of the electrolyte layer deposited on the support surface was greatly affected by the shrinkage of tubular support during the co-sintering process. Support shrinkage above 15% was found to produce a fully densified electrolyte layer on the anode support. In contrast, the use of an anode support with shrinkage below 10% constrained gadolinium-doped ceria (GDC) sintering, resulting in a poorly densified GDC microstructure. Finally, we obtained a micro-tubular cell composed of a dense GDC and a porous (La,Sr)(Co,Fe)O3–GDC multi-layered structure on a NiO–GDC micro-tubular anode support. The cell, with a dense and ≈15μm thick GDC electrolyte layer, was electrochemically evaluated in a temperature range from 450 to 550°C. This micro-tubular cell with an electrode length of 6.3mm showed a power density above 0.1, 0.2 and 0.4W/cm2 at 450, 500 and 550°C, respectively, in wet H2 fuel flow. [Copyright &y& Elsevier]

Abstract: Functionally graded cathodes for honeycomb solid oxide fuel cells are prepared using sol-gel/slurry coating techniques. The compositions of the cathodes are gradually changed from a material that is active for oxygen reduction and more compatible with the electrolyte (e.g., LSM for YSZ) to another material that is more conductive for current collection. The microstructure and electrochemical properties of the electrodes are systematically characterized using electron microscopy and electrochemical impedance spectroscopy. The cathodic interfacial polarization resistances for a graded cathode fired at 900 °C are 0.21 and 0.10 Ω cm2 at 700 and 800 °C, respectively. The impedance spectra indicate that at least two separate processes contribute to the overall polarization resistances. The effects of cathode fabrication temperature and oxygen partial pressure on the high- and low-frequency impedance responses are studied in detail. [Copyright &y& Elsevier]

Historically, electroplated coatings have always represented the most cost-effective method for applying deposits of metals and alloys that were pure and dense, mirroring in general the properties of the parent metal. For engineering purposes, particularly in conversion industries, such as steel manufacturing, and primary industries, such as oil extraction, coating specifications and expectations far exceed conventional coating capabilities. In response to these requirements, a composite coating technology has been developed, which consists of a hard metal component from the tungsten carbide family of coatings and a hard refractory oxide layer produced from a slurry coating. Capable of functioning in extreme environments where temperature, corrosion, abrasion, fatigue, friction and erosion are merely starting blocks in the design of a coating system, this composite coating technology shows significant technical and commercial advantage. In the oil exploration and extraction industry, field studies have shown the composite coating to exceed by two orders of magnitude the life expectancy of conventional coatings in high-temperature, heavy particulate-laden fluids, which are therefore very abrasive, with salinity in excess of 360 000 ppm of chloride ions. In the steel industry, continuous casting mould plates have shown an increase in life expectancy of between four- and eight-fold. With virtually unmeasurable low wear rates, there are marked improvements in the downstream surface quality of the billets and slabs, while at the same time the integrity of the original copper asset is maintained. [Copyright &y& Elsevier]

In this study, the mechanical resistance and the thermal insulation potential of novel thermal barrier coatings (TBCs) made of a foam of hollow alumina particles are assessed through scratch testing, micro-indentation and thermal diffusivity measurements using laser-flash. The thermal diffusivity of the foam coatings ranges between 0.6 × 10−7 and 5 × 10−7 m2·s−1 and is thus comparable with the thermal insulation potential of the standard plasma-sprayed (PS) and electron beam–physical vapour-deposited (EB-PVD) TBCs made of yttria-stabilised zirconia (YSZ). The coatings annealed in more oxidative atmospheres exhibit greater mechanical resistance due to the thickening of the alumina shells and the increased sintering of the foam. However, when the oxidation is poorly tailored, the adhesion of the foam to the substrate decreases due to the presence of unwanted oxide that grows at the substrate/coating interface. [ABSTRACT FROM AUTHOR]