Papers by Keyword: Spray Deposition

Abstract: Dye-sensitized solar cells utilize a transparent conductive oxide (TCO) glass which is mainly Fluorine-doped tin oxide (FTO) for the working electrode and counter electrode. The TCO is one of the important parts of DSSC. TCO glass becomes the part that determines the price of mass production of DSSC. Low-cost TCOs with high conductivity and high light transmittance are required. In this study, We proposed a simple fabrication of TCO glass by spray deposition method of Tin (II) Chloride (SnCl₂) on top of the lime glass substrate. Fabrication was started with 3 mm of Lime glass cleaned with distilled water and ethanol in sonication for 15 minutes and 10 minutes heating at 500°C. The variation of layer thickness was performed by multilayer spray using 2 mg SnCl₂ and 5 ml ethanol mixture and then baked for 10 minutes at 500°C. The electrical conductivity, light transmittance, and roughness of the glass at one spray layer were 20 Ω/cm², 87.1 %, and 0.010 µm respectively, and decrease along with the increase of the number of spray layers. A multimeter, UV-VIS Spectrophotometer, and 3D Measuring Laser Microscope are used to measure these parameters in this study. Compared to the properties of commercially available Fluorine doped Tin Oxide (FTO) glass, this method can be used as an alternative for conductive glass production for Dye-Sensitized Solar cells.

Abstract: Spray deposited SiCP/Al-Fe-V-Si composite is characterized with pores and oxide films between deposited particles, therefore further densification is needed. Densification of the composite preforms in large size has becomes the research emphasis and challenge. Current research of the composite is focused on densification technologies used to eliminate metallurgical defects. Key parameters of wedge pressing, density and stress distribution, flow behaviour, densification mechanism and regularity are investigated by combining experiment and finite element modelling. Pass reduction of 10%~15% and space of about 10mm between one end of the plate blank and the steel mould is beneficial to wedge pressing because of the effective deformation. Density and stress of the external layer are higher than that of the inter layer, density and stress distribution become uniform with overall reduction. Materials in preformed area flows along thickness direction as thickness of the plate decreases, while materials in main deformation area flows along length direction with increasing length of the plate. Wedge pressing of the spray deposited Al matrix composite plate follows porous metal plastic deformation mechanism under the condition of plane strain. Practical relative density of the plate is higher than the calculated value in the initial stage of pressing, while the practical relative density becomes lower than the calculated value as true strain exceeds 0.55, which can be attributed to the pores resulted from aggregation and breaking of SiC particles.

Abstract: The development of hard coating based on colloidal silica nanoparticles on polymethyl methacrylate (PMMA) sheet was reported. The colloidal silica was surface-modified with methyltrimethoxysilane (MTMS) and formulated to hard coating solution via sol-gel process. The hard coating solution was applied to PMMA surface by spray deposition technique. Spraying process was carried out from spray nozzle outlet diameter of 0.35 mm and air compress pressure at 0.2 MPa with nozzle to substrate distance at 10 cm. The different coating thicknesses were obtained by adjusting the amount of coating applied. The optimal coating thickness that gives the highest pencil-hardness at 7H and 100% adhesion for adhesion tape test is 10 μm.

Abstract: An innovative spray deposition technique has been applied to produce in situ TiB₂/Zn-30Al-1Cu composites. The microstructures of the spray-deposited composite were studied using optical microscopy, scanning electron microscopy, and X-ray diffraction. Both theoretical and experimental results have shown that the TiB₂ particulates are formed in the microstructure. It was found that the TiB₂ particles were distributed in Zn-30Al-1Cu matrix uniformly, and the TiB₂ particles are about 2 μm in size. Moreover, the presence of the TiB₂ particles was led to increasing of α’ phase with less 2 μm size in the composites which have a tendency to decompose to α+η structure.

Abstract: The wear and corrosion resistance of working surfaces can be improved by applying suitable coatings using thermal spray techniques. In the present work air plasma spray deposition technique (PSD) was used to coat Al₂O₃ ceramic powder on AISI 410 grade stainless steel. The steel substrate was primarily coated with Ni/Cr which acts as a bond coat for good fastening. Surface morphology of Al₂O₃ particulates of the coating was examined by scanning electron microscope (SEM). Uniform distribution of the Al₂O₃ particles on Ni/Cr pre-coated steel substrate was observed. Sliding wear tests under dry condition were conducted for different sliding velocity by keeping applied normal load and sliding distance constant. The results indicate significant improvement in the wear resistance of Al₂O₃ coated stainless steel substrate using PSD. The micro hardness of Al₂O₃ coated surface was found to be higher than that of the base metal.

Abstract: The microstructures and thermal stabilities of high silicon aluminum alloys prepared by spray deposition (SD) and subsequent heat treatment were studied. The results indicate that the size of the primary silicon in the deposited ingots is much smaller than that prepared by normal casting. After the subsequent heat treatment, the pores in deposited ingots are disappeared and their density increase to about 100%. While the size and volume fraction of the primary silicon in solidified hypereutectic Al-Si alloy increase with the increasing of silicon content, the corresponding thermal expansion coefficient decreases.

Abstract: An innovative spray deposition technique has been applied to produce in situ TiB₂/Zn-30Al-1Cu composites. The microstructures of the spray-deposited composite were studied using scanning electron microscopy, transmission electron microscope and X-ray diffraction. The results have shown that the TiB₂ particulates are formed in the microstructure. It was found that the TiB₂ particles were distributed in Zn-30Al-1Cu matrix uniformly, and the TiB₂ particles are about 2μm in size.

Abstract: In this study, Mg-6.8Gd-4.5Y-0.5Zr alloy was fabricated by the spray atomization and deposition technique. The microstructure and mechanical properties of the alloy were studied using optical microscopy, scanning/transmission electron microscopy, X-ray diffraction, and tensile tests. The secondary phases in the microstructure of the spray-deposited alloy were examined. The tensile test results indicate that the spray-deposited Mg-6.8Gd-4.5Y-0.5Zr alloy displays superior tensile strength due to grain refinement and the presence of precipitating strengthening phases.

Abstract: A Tungsten oxide (WO₃) film on top of a glass substrate had been successfully constructed. The immobilization of tungsten oxide was performed using spray-deposition method. The precursor volume was varied as 5 mL, 10 mL and 25 mL. Characterization using XRD and SEM yield that precursor volume influence the quality of the film. It was found that the good uniform film was obtained using precursor volume 5 mL and 10 mL. The crack which was resulted from non-uniformity of the film appear when the precursor film was 25 mL.

Abstract: The major reason that there is not more widespread use of titanium and its alloys is the high cost. In this paper, developments in one cost effective approach to fabrication of titanium components - powder metallurgy - will be discussed under various aspects of this technology. The aspects to be discussed are the blended elemental approach, pre-alloyed techniques, additive layer manufacturing, metal injection molding, spray deposition and microwave sintering. A brief review of a number of low cost powder production processes is also presented.