Sinterable La0.8Sr0.2CrO3 and La0.7Ca0.3CrO3 powders by sucrose combustion synthesis

Air atmosphere sinterable La0.8Sr0.2CrO3 [LSC] and La0.7Ca0.3CrO3 [LCC] powders have been prepared by sucrose combustion synthesis. Aqueous solution containing stoichiometric quantities of the metal nitrates and sucrose (3 moles/mole of the metal ion) at pH ~1 was concentrated by heating on a hot plate into a viscous resin which on drying at 120 C produced a foam with interconnected pore structure. This foam ignited with a matchstick in a combustion set up fabricated in the laboratory produced ashes consisting of loose aggregate of LSC and LCC particles. The loose aggregates of LSC and LCC were powdered by planetary ball milling to submicron size particles with D50 value 0.19 and 0.60 lm, respectively. The surface area of the LSC and LCC powders was 23 and 19 m2/g, respectively. Pellets prepared by cold compaction and sintering of LSC and LCC powders in air atmosphere showed density 96.8 and 98.8% of theoretical value respectively. Sintered LCC sample showed finer grains compared to the LSC sample under identical processing conditions.