The effects of temperature, holding time and salt amount on formation of nano CaZrO3 via molten salt method

Nano-particles of CaZrO3 were successfully synthesized at 800 degrees C using the molten-salt method, and the effects of processing parameters, such as temperature, holding time and amount of salt on the crystallization of CaZrO3 were investigated. Na2CO3, CaCl2 and nano-ZrO2 were used as starting materials. On heating, Na2CO3 reacted with CaCl2 to form NaCl and in situ CaCO3. Na2CO3-NaCl molten eutectic salt provided a liquid medium for reaction of CaCO3 and ZrO2 to form CaZrO3. The results demonstrated that CaZrO3 started to form at about 700 degrees C and that, after the temperature was increased to 1000 degrees C, the amounts of CaZrO3 in the resultant powders increased with a concomitant decrease in CaCO3 and ZrO2 contents. After washing with hot-distilled water, the samples heated for 3 h at 800 degrees C were single-phase CaZrO3 with 70-90 nm particle size. Furthermore, the synthesized CaZrO3 particles retained the size and morphology of the ZrO2 powders, which indicated that a template formation mechanism dominated the formation of CaZrO3 by molten-salt synthesis. (c) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.