A simple method for making a porous SiC body through a polymeric route at one firing processing was demonstrated by the sacrificial filler template approach. By incorporating sacrificial pore-forming plastic powder, PMMA microbeads, into liquid preceramic polymer, AHPCS, and losing it after the polymer was hardened, a preceramic porous body was formed. As a consequence of systematic examination of the effects of particle size and mixture ratio of the powder, an AHPCS-derived porous SiC body was reproducibly formed without critical crack initiation. It was enabled only when the polymer was sufficiently contained to make a strong skeletal structure with the sacrificial plastic particles closely distributed. The porous microstructure would contribute to efficient gas emission and uniform thermal shrinkage during polymer pyrolysis, which reduced internal pressure and crack-causing thermal stress.
A novel production method for porous metal components has been developed by
applying powder space holder (PSH) method to metal powder injection molding (MIM) process.
The PSH-MIM method has an industrial competitive advantage that is capable of net-shape
manufacturing the micro-sized porous metal products with complicated shapes and controlled
porosity and pore size. In this study, the small impeller with homogeneous micro-porous structure
was manufactured by the PSH-MIM method using porous compounds composed of fine stainless
steel 316L powder and polymethylmethacrylate (PMMA) particle. The effects of combinations in
size and fraction of PMMA particle on dimensional tolerance and variation of sintered porous
specimens were investigated. It was concluded that the PSH-MIM method could manufacture
commercially micro-porous metal components with high dimensional accuracy.
The production method for metal components with micro sized porous structure has been developed by applying “powder space holder method” to metal powder injection molding process. In this study, a co-sintering process was utilized to make a plate of sintered metal with micro porous graded structure. The green compact sheets with various contents of space hold particles were prepared by hot press molding for simplification. The five layers of metal with symmetric structure, which the skin layer was formed with high density metal and the core was formed with open or closed porous structure, or with inverse symmetry, was obtained by changing stacking sequence in co-sintering process. Mechanical properties of the materials with plain homogeneous porous structure and porous graded structure were compared. The usefulness of proposed method for producing the metal components with micro porous graded structure and the effective of graded structure to compensate the deficiencies on the mechanical property of porous metals was shown.
A novel production method for the metal components with micro-sized porous structures has been developed by applying the powder space holder (PSH) method to the metal powder injection molding (MIM) process. This production method is compatible with widespread applications with high functionality such as heat sinks, electrodes and medical implants and so on. These applications can benefit from the advantages provided by micro-porous metal components with complicated shapes using most kinds of metal powder. The aim of this study is to clarify the effects of material combinations and production conditiorfs on the pore formation and some physical properties of sintered porous metals. The green compacts were molded via uniaxial hot pressing for an experiment using various porous compounds which were prepared by changing the combinations in size of stainless steel 316L powder and polymethylmethacrylate (PMMA) space holding particle. Afterwards they were sintered at various temperatures after thermal debinding. It was confirmed that the size of metal powder and space holding particle together with the sintering temperature were main 'Correspondence to Prof. K. Nishiyabu factors affecting the pore size, porosity, surface area and shrinkage of sintered porous metals. It was concluded that the PSH-MIM method proposed was useful for producing metal components with micro-sized and high functionally porous structures.
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