Mechanically Enhanced Open Porous Materials by a HIP Process

Abstract

Open porous materials were produced by a Hot Isostatic Press (HIP) process. Cold-isostatically pressed powders were directly heated to a normal sintering temperature under HIPping conditions. The products were characterized by open pores and were almost free from closed pores. Those open pore materials are typically useful as filters, reactor beds, grinding materials and so on. A grind stone with silicon carbide grains with aluminium nitride bridges was discussed as an example. At the sintering temperatures of AlN above 1973K, 20 to 30% of open porosity was maintained in the HIPped samples, On the other hand, normally heated ones were almost fully densified. Since no additives for pore formation were used, uniform pore size distribution and homogeneously dispersed pores were expected by the new HIP process. Normal HIPping effects enhanced the properties of bridge parts by reducing defects and also closed pores in them. Better strength and open porosity were obtained by this method.