Effects of sintering temperature on phase, physical properties and microstructure of ca<inf>3</inf>co<inf>4</inf> o<inf>9</inf> ceramic

Abstract

© 2018 Trans Tech Publications, Switzerland. This study investigated the effects of sintering temperature on phase, physical properties and microstructure of calcium cobalt oxide (Ca3 Co4 O9 or CCO) ceramic. CCO powder was prepared with using the mixed oxide method and calcined at 750°C for 24 h. The ceramics were prepared by sintering the powder at 900, 950, 1000 and 1050°C under a normal air atmosphere for 24 h. A maximum density of 4.02 g/cm3 (~92% relative density) with 12% linear shrinkage was obtained in the sample sintered at 1000°C. XRD patterns of the CCO ceramics indicated pure phase with no detected impurity. SEM images of the ceramics showed plate-like shaped grains. The average grain size value gradually increased as the sintering temperature increased, and reached a maximum value of 8.95 µm at the sintering temperature of 1000°C. The deviation from stoichiometric composition for the samples sintered at low sintering temperatures may be due to the low sample density which in turn affected the EDS analysis results.