Low-temperature sintering of La(Ca)CrO<SUB>3</SUB> powder prepared through the combustion process

Ultrafine La(Ca)CrO<SUB>3</SUB> (LCC) powder was prepared through the glycine–nitrate gel combustion process. It was shown for the first time that the use of relatively inexpensive CrO<SUB>3</SUB> as a starting material for chromium has potential for the bulk preparation of sinter-active LCC powder. As-prepared powder, when calcined at 700°C, resulted in LCC along with a small amount of CaCrO<SUB>4</SUB>. The calcined powder was found to be composed of soft agglomerates with a particle size of ≈70–290 nm. The cold pressing and sintering of the calcined powder at 1200°C resulted in the mono-phasic La<SUB>0.7</SUB>Ca<SUB>0.3</SUB>CrO<SUB>3</SUB> with density ≈98% of its theoretical value. This is the lowest sintering temperature ever reported for La<SUB>0.7</SUB>Ca<SUB>0.3</SUB>CrO<SUB>3</SUB>. The conductivity of the sintered La<SUB>0.7</SUB>Ca<SUB>0.3</SUB>CrO<SUB>3</SUB> at 1000°C was found to be ≈57 S/cm in air. The sintering and electrical behavior achieved for La<SUB>0.7</SUB>Ca<SUB>0.3</SUB>CrO<SUB>3</SUB> may find application as an interconnect material for high-temperature solid oxide fuel cells if problems with chemical expansion and poor conductivity in fuel can be overcome