THERMOCHEMICAL ETCHING METHOD FOR CERAMICS

A thermochemical etching procedure, comprising a short chemical etch followed by a low-temperature thermal anneal (typically 10 min at less than or similar to 70% of the sintering temperature), has proved successful for the preparation of alumina, aluminum nitride, and nickel zinc ferrite ceramics for microstructural studies. Good-quality results have been achieved in times much shorter than those normally associated with chemical etching and at temperatures lower than those usually used for thermal etching. Under such conditions, grain growth and surface modification are believed to be minimal.