The Effects of Firing Temperatures and Dwell Time on Phase and Morphology Evolution of LaNi0.6Fe0.4O3 Ceramics Prepared via the Combustion Technique

Abstract

The optimization of the preparation condition of single phase LaNi0.6Fe0.4O3 or LNF by the combustion technique was examined. The phase formation and the crystal structure were investigated using X-ray diffraction pattern. The highest percent of the perovskite phase at 93.5% was exhibited in the sample calcined at 1000°C for 4 h and repeatedly calcined again at 1200°C for 4 h. A higher than optimum calcination temperature lead to an occurrence of a secondary phase which included a tiny amount of La4Ni3O10. After being sintered between 1250–1450°C for 2 h, the pure perovskite phase was obtained from the samples sintered in the range of 1250 to 1350°C while a higher sintering temperature induced a tiny amount La4Ni3O10. Moreover, increasing the sintering temperature affected the crystal structure which changed from rhombohedral to orthorhombic. The SEM observation revealed that the grain boundaries of sintered ceramics melted when the sintering temperature was higher than 1300°C. From the SEM and density investigation, the results proved that the optimum sintering condition is 1300°C for 2 h. Using the combustion technique, both firing temperature and soaked time is lower than the conventional method preparation.