Phase Transitions and Transient Liquid‐Phase Sintering in Calcium‐Substituted Lanthanum Chromite

Abstract

This paper investigates sintering and phase transitions of La 0.7 CaxCrO 3 (0.25≥x≥0.35), a material useful as electrical interconnections in solid oxide fuel cells. Heating of the quenched, metastable single‐phase chromite resulted in exsolution of CaCrO 4 due to Ca solubility limitations below 1200°C. A transient liquid phase formed between 850° and 1000°C as the CaCrO 4 melted, causing partial densification in materials having 0.25 < x < 0.30. A slight increase in Ca content induced an additional liquid‐phase sintering event, likely due to melting of Ca 3 (CrO 4 ) 2 , which facilitated near‐complete densification by 1250°C. After enhancing sintering, the secondary phases redissolved into the chromite.