Crystal growth behavior of La _0.8 Ca _0.2 Cr _0.2 Al _0.8 O ₃ nanopowders prepared via sol–gel process

Abstract The effects of the addition of acetic acid (HAc) and ethanol on the phase structure and crystal growth behavior of the La 0.8 Ca 0.2 Cr 0.2 Al 0.8 O 3 nanopowders prepared via the sol–gel method were investigated. As a result, the La 0.8 Ca 0.2 Cr 0.2 Al 0.8 O 3 nanopowders with a stable hexagonal structure were successfully fabricated after heat treatment at 1400°C using a low acetic acid content. The activation energy of crystal growth increased first and then decreased with the increase of HAc or ethanol addition. In comparison, the increment in the quantity of HAc had a more pronounced effect on the activation energy of crystal growth. Correspondingly, the crystallite size of final products was controlled to be 37.14 nm, and the lowest activation energy (22.47 ± 0.46 kJ/mol) for crystal growth of La 0.8 Ca 0.2 Cr 0.2 Al 0.8 O 3 nanopowders was obtained with deionized water as the solvent and the M/HAc molar ratio of 2:1, which was beneficial to the crystallization of La 0.8 Ca 0.2 Cr 0.2 Al 0.8 O 3 grains.