Advanced Materials Research Vol. 1133

Abstract: The effect of rare earth additions on diffusion and porosity deformation of Al-11Si-Cu alloy was investigated. The microstructure was characterized by optical microscope. By adding small amount of La and Ce, the porosity can be reduced. As the amount of La and Ce were increased, the porosity defects were diffused and increased in microstructure. RE intermetallic indicates Al-Cu phase interrupted the quality of Al-Si-Cu casting alloy.

Abstract: Stainless Steel materials (SS316L) generally known as a highly wear performance and resistant to corrosion. The purpose in this study is to produce the stainless steel foam and physical properties of sintered 316L stainless steel materials produced by powder metallurgy (P/M) method. In this paper, the method is based on using spherical urea as space holder was investigated. Then, the foams will be given to consider the properties of SS316L foam after sintering process. Powder metallurgy process needs to go through the mixing, pressing, sintering and analysis. The selected compositions of SS316L were varied from 50 wt % to 60 wt % SS316L, respectively while the remaining percentages are foaming agent. The SS316L powders were cold-pressed with 8 tons pressure and sintered at 1200°C via tube furnace. The SS316L foams were then characterised using Scanning Electron Microscopy (SEM) for morphological characterisation of the samples after sintering process. Lastly, porosity and density were tested for this sample. As a result, the composition with 60 wt % SS316L is provided higher bulk density and lower porosity which are 4.34 g/cm3 and 69.03 %, respectively.

Abstract: Replication or slurry dipping is a simple and popular method of producing porous and interconnected foams using a metallic slurry. The advantage of the network-like metal foams is it exhibits a natural bone-like structure which enables ingrowth of bone cells and blood vessels. The aim of the present study was to investigate the physical properties of Cobalt Chromium Molybdenum (CoCrMo) foams after sintering process using vacuum furnace. The CoCrMo slurry was prepared by using different composition of CoCrMo powder which was 50wt%, 55wt%, 60wt%, 65wt% and 70wt%. The CoCrMo slurry was produced by mixing CoCrMo powder with Polyethylene Glycol (PEG), Carboxyl Methyl Cellulose (CMC) and distilled water. Then, polymeric foam template was impregnated in CoCrMo slurry and dried at room temperature. Sintering was carried out in a high temperature vacuum furnace at 1300°C. The CoCrMo foam was characterized by using a Scanning Electron Microscopy (SEM) analysis. The physical properties of CoCrMo foam was analyzed by porosity and bulk density test that was Archimedes method. From the study it was expected that the composition of metallic slurry play important roles to produce a CoCrMo foam. The best composition that obtained in this experiment was 70wt%. The porosity and density value for 70wt% of composition were 20.3% and 2.63g/cm3. The higher composition of metallic slurry will decrease the density and will increase the porosity.

Abstract: A well-designed experimental were conducted with L₁₈ Orthogonal Array (OA) based on the Taguchi method with input factors discharge current, pulse on time, lift time and flushing pressure. Micro hardness was measured and the mean of the observed values were plotted. The factors effecting the micro-hardness of the work-piece has been obtained. It is inferred that micro-hardness value increases with increase in discharge current and decreases with increase in Pulse on Time. The optimal condition for minimum hardness was found to be discharge current (Ip) = 2A, pulse on time (Ton) = 500μs, lift time (Tup)= 1.4 ms and flushing pressure (Fp)= 0.2 kgf/cm².

Abstract: Optimization of solvent debinding process parameters for powder injection molded 316L stainless steel (SS) has been reported in this research work. Powder gas atomized (PGA) 316L SS was blended with a multicomponent binder in Z-blade mixer at 170°C ± 5°C for 90 minutes. Feedstock was successfully injected at temperature 170 ± 5°C. Injection molded samples were immersed in n-heptane for 2h, 4h, 6h and 8h at temperatures 50°C ,55°C and 60°C to extract the soluble binder components. Scanning electron microscope (SEM) results attested that soluble binder components were completely extracted from injection molded samples at temperature 55°C after 6h.

Abstract: MIM technique is described in which allows for the production of highly porous metallic foams with porosity levels up to 90%. It makes use of the pressure built up by the decomposition of a foaming agent which is incorporated in a foamable precursor copper material obtained by powder compaction. A suitable behaviors feedstock that refers to its rheological is one of the key factors to ensure the successful of MIM technique and to predict failure, whether due to the binder component and compositions, powder loading or unsuitable process parameters. Potassium carbonate and polyethylene is added and were mixed homogeneously to form a copper feedstock. The rheological results in term of shear rate, shear stress, viscosity, melting rate and softening temperature which related to pseduoplastic behaviors have been conducted using a capillary rheometer (CFT-500D, Shimadzu) at various temperature and loads. The result has indicated that the viscosity of the feedstock is decreased with increasing shear rate thus proved the feedstock to be pseudoplastic.

Abstract: Metal Injection Moulding (MIM) has undergone development of various binder systems with the aims of shortening the overall debinding time duration. In the present work, binder system based on biopolymer has been utilised in injection moulding of hip stem CoCrMo alloy powder. The feedstock consisted of CoCrMo powder with mean diameter particle size of 16μm and binder system which comprised of major fraction of wax and minor fraction of polyethylene. The moulded part was immersed into n-heptane at 60°C in order to remove the paraffin wax and stearic acid, followed by sintering in a controlled vacuum atmosphere. Results showed that solvent extraction debinding technique allowed complete removal of paraffin wax and stearic acid from the injection moulded part within 5 hours without swelling or distortion of the debound part. Lower heating rate needed during thermal pyrolysis in order to retain the shape due to the thickness of the part.Keywords: CoCrMo, MIM, wax, debinding,

Abstract: An experimental study was conducted to investigate the effect of EDM die sinking machining parameters on surface roughness of Stavax material for mould insert. The spark gap, peak current and servo voltage were manipulated to find the best combination of EDM machining parameters. The surface roughness of the machined surface of each specimen was measured using Perthometer and the image of texture was observed by using optical microscope. It was observed that the surface roughness was highly affected by the spark gap and peak current whereas the servo voltage had little effect.

Abstract: In this study, HP/ENR blends were prepared in aqueous solution with different hydrophilic polymers for rubber glove donning coating application. HP/ENR blend films were prepared using cast films technique to investigate the film formation prior to coating onto rubber glove. The films surface morphology were characterised using Scanning Electron Microscopy (SEM) and Light Microscopy (LM). While, the thermal properties of the films were determined using Differential Scanning Calorimetry (DSC). The microscopy results showed that coherence film formation can be obtained even though the PVA/ENR and PAA/ENR blends were immiscible. DSC result showed that the glass transition temperature (T_g) of the blends shifted to higher temperature compared with T_g of ENR. The preliminary evaluation of coating onto rubber latex film indicated that PVP/ENR blend is feasible as coating material.

Abstract: Ceramic oxide thin films are an important material, with applications in many areas of science and technology. Titanium oxide (TiO₂) is also a well-known and important material for applications such as gas sensors [1], photocatalysis materials [3], and electrochemicals [1], due to its self-cleaning [2], good corrosion resistance and biocompatibility. Atomic Layer Deposition (ALD) is a nanotechnology tool that is used for the deposition of nanostructured thin films. The unique advantage of ALD is the self-limiting film growth mechanism, which offers attractive properties, simple and accurate film thickness control, sharp interfaces, uniformity over large areas, excellent conformality, good reproducibility, a multilayer processing capability, and high quality films at low temperatures [3, 4]. TiO₂ thin films were grown using TTIP (Titanium isopropoxide) ALD on silicon wafers, glass slides, and stainless steel plates in order to study the effect of substrates on the growth of TiO₂. In order to achieve the desired advantages of using TTIP, a series of experiments were performed to study the growth mechanism of TiO₂ thin films using TTIP and H₂O by ALD.