Applicability of nitride powders as foaming agents in superplastically foamed ceramics

Abstract

The applicability of several nitride powders for use as foaming agents in superplastically foaming ceramics was investigated. Ceramic mono-foams were fabricated successfully using AlN and Si₃N₄ foaming agents. By using BN as a foam agent, on the other hand, we cannot fabricated well developed ceramic foams due to cracking and fracture. When the quantity of foaming agent was increased, the porosity increased to a certain amount, then saturated. With equal amounts of Si₃N₄, the porosity from the dispersed foaming agent was higher than that obtained from a monolithic compact without mixing, which was similar to the case of SiC foam agent.