The hardcoat anodising process was done by using different concentration of H2SO4 from 0% to 20%. The 90 volt of anodising process was applied by using Al foil as cathode materials. The surface changes on PM Al-Mg resulted by hardcoat anodising was characterised by XRD measured. Surface hardness was measured by Micro-Vickers hardness machine. The experiment found different XRD pattern between anodised PM Al-Mg samples. The study was found by that the optimum value for H2SO4 concentration was 15 % H2SO4 and result 26 μm thickness, 5.07% of mass changes and HVN 105.4 hardness. The hardcoat anodising was affected to the XRD pattern for PM Al-Mg.
This paper reports on the effects of HAP addition and sintering temperature on the microstructure and properties of the F-75/HAP composites fabricated by powder metallurgy. Co-Cr-Mo (F-75) is used in orthopedics because of its excellent biocompatibility when implanted to human or animal body. Hydroxyapatite (HAP) powders have been used as fillers because HAP is the one of the most effective biocompatible materials with similarities to mineral constituents of bones and teeth. HAP powders (chemical formula Ca10(PO4)6 (OH)2) have been added to Co-Cr-Mo alloys in composition of 0 to 10 wt. %. The mixtures were then milled, cold compacted at 550 MPa, before sintered at 1100 and 1200°C in a tube furnace. The density, porosity, microhardness and compressive strength were measured. The composites that have been sintered at temperature 1200°C showed better physical and mechanical properties than those produced at 1100°C. After sintering at 1200°C, the samples show higher density, compared with the sample sintered at 1100°C. The sample with no HAP which have been sintered at 1200°C has the highest microhardness (208.9 HV), compared with the same sample sintered at 1100°C (194.3HV). As the temperature is increased from 1100 to 1200°C, the value of compressive strength increased from 184.538 to 341.086 MPa. Microstructural analysis for line scan showed that, as the sintering temperature was increased, there was good interface bonding between HAP particles and matrix F-75.
A study of wear behaviour on anodised PM aluminium matrix composites (AMC) reinforced with Saffil™ alumina short fibres was done. AMC was fabricated by powder metallurgy methods (PM) with using Al flake powders and Saffil™ alumina short fibres. AMC reinforced with 15 wt % Saffil¥ alumina short fibre was selected because it showed optimum mechanical and physical properties. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time on MMC. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20 % volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Scanning electron microscope (SEM) was used to investigate coating morphology and thickness. From the research, anodising voltage of 18 V and 15 % vol H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. SEM showed the coating thickness around 20 Pm. From the reserch, it was found that H2SO4 anodising was able to give good coating to MMC.