PHASE-TRANSITIONS AND TRANSIENT LIQUID-PHASE SINTERING IN CALCIUM-SUBSTITUTED LANTHANUM CHROMITE

This paper investigates sintering and phase transitions of La0.7CaxCrO 3 (0.25 less than or equal to x less than or equal to 0.35), a materia l useful as electrical interconnections in solid ol;ide fuel cells. He ating of the quenched, metastable single-phase chromite resulted in ex solution of CaCrO4 due to Ca solubility limitations below 1200 degrees C. A transient liquid phase formed between 850 degrees and 1000 degre es C as the CaCrO4 melted, causing partial densification in materials having 0.25 < x < 0.30. A slight increase in Ca content induced an add itional liquid-phase sintering event, likely due to melting of Ca-3(Cr O4)(2), which facilitated near-complete densification by 1250 degrees C. After enhancing sintering, the secondary phases redissolved into th e chromite.