MECHANICAL-PROPERTIES OF HOT ISOSTATICALLY PRESSED ZIRCONIUM NITRIDE MATERIALS

The influence of powder properties on the sintering behaviour, the mic rostructural development and the mechanical properties of hot isostati cally pressed (HIPed) zirconium nitrides were investigated. The result s show that the densification behaviour is dependent on the powder cha racteristics, more precisely the grain morphology and size, and oxygen , carbon and metallic impurity contents. The mechanical properties are controlled mainly by the amount of porosity and the presence of a com plex intergranular phase in direct relation to the purity of the start ing powder. The differences in the fracture strength and toughness bet ween the two grades are perceptible. On the other hand, the thermal sh ock resistance to fracture initiation, as well as the elastic paramete rs of both dense materials, are similar.