Effect of Firing Temperatures on Phase and Morphology Evolution of CaZrO₃Ceramics Synthesized Using the Combustion Technique

Abstract

The effects of calcination temperatures (900-1400 • C) and sintering temperatures (1400-1650 • C) on phase and morphology evolution of perovskite CaZrO 3 ceramics were studied. The results obtained from DTA-TGA analysis were used to determine the processed conditions of various calcination temperatures. The highest purity of the orthorhombic perovskite phase was obtained from powder calcined at 1200 • C and the pure phase was detected in sintered ceramic samples below 1650 • C. The SEM results showed that the average particle size and the average grain size of samples increased with the increase of firing temperatures. The shrinkage of ceramics increased as the sintering temperatures increased. The calcium zirconate, which had around 97.6% of the theoretical density, was obtained from the sample sintered at 1500 • C for 2 h. More importantly, the highest density with low sintering temperature were be improved by the combustion technique.

Phase Evolution, Microstructure and Dielectric Properties of CaCu3Ti4O12Ceramics Fabricated by Combustion Technique

“…The densification mechanisms during treatment corresponded to the grain growth, especially during the final stage of sintering. The expansion of trapped gases in the pores assembled and grew as a result of the grain growth [15,17]. This result agreed with the microstructure and XRD result of the ceramic and proved that high density of CCTO ceramics could be prepared by the combustion technique.…”

“…The reaction can occur easily in a liquid system because the diffusion coefficient is higher than in a solid medium [17][18]. The obtained ceramics have a high density and excellent electrical properties with a low firing temperature and a short soaking time [15][16][17][18]. Furthermore, the preparation and characterization of CaCu 3 Ti 4 O 12 (CCTO) ceramics, using the combustion technique, have not been reported in the literature.…”

“…Our recent work has successfully fabricated ferroelectric ceramics using the combustion technique [15][16][17][18]. This technique involves a self-sustained reaction between the reactive materials and the fuel (e.g., urea and glycine) which supplies a liquid medium at the start of the reaction.…”

Preparation and Application of the Sol–Gel Combustion Synthesis-Made CaO/CaZrO3 Sorbent for Cyclic CO2 Capture Through the Severe Calcination Condition

“…6. It could be observed that the mean grain size of CaZrO 3 is stabilized around 74 nm either in the fresh Ca 8 Zr 2 or in its carbonated products after the different cycles for its good phase stability [51]. Different from the stable grain size for CaZrO 3 , a little increase in the mean grain size of the carbonated product CaCO 3 is observed from 43.3 nm after the 5th cycle to 45.5 nm after the 18th cycle mainly because the formed CaCO 3 owns the low resistance to sintering for its lower Tammann temperature of only 533°C, as compared to that of CaO as 1313°C [4] and thus much inferior to sintering, which incurs the agglomeration of the newly formed CaCO 3 grains and further growth in their grain size [26].…”

“…5. The SGCS-made Ca 8 Zr 2 is found to consist of CaO and CaZrO 3 instead of ZrO 2 , where CaZrO 3 is easily formed by the interaction of CaO with ZrO 2 and displayed great superiority in contrast to ZrO 2 for its high melting temperature, thermal and chemical stability, good thermal shock resistance and low thermal expansion coefficient [46,51,52]. Besides the binder CaZrO 3 and the carbonated product CaCO 3 , a little CaO is left and does not react with CO 2 .…”