Crystallisation of Calcium Stabilised Zirconia Solid Solutions in the Ammonium Nitrate Liquid

摘要

A co-precipitation method, in which zirconyl and calcium nitrates are used, was applied to prepare sinterable powders in the CaO-ZrO_2 system. Concentrated ammonia or saturated solution of ammonium oxalate in concentrated ammonia was used as precipitating agents. Calcination of deposits was performed in the mother environment formed by ammonium nitrate liquid. Crystalline phases were detected in the samples heated at temperatures as low as 250°C regardless of chemical composition of zirconia powder and the precipitating agent applied. A segregation of CaO was detected during crystallisation of calcia-zirconia solid solutions. The mechanism of crystallisation and usefulness of the method in preparation of Ca-TZP and Ca-CSZ materials were discussed.