The effect of raw materials particle size on synthesis of nano-CaZrO3 via molten salt method

Nano-CaZrO3 was successfully synthesized at 800 oC using the molten-salt method, and the effect of raw materials particle size on the formation of CaZrO3 were investigated. Na2CO3, CaCl2, nano-ZrO2 and micro-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 in both nano- and micro-ZrO2 inclusive samples, CaZrO3 started to form at about 700 oC and that, after the temperature was increased to 1000 oC, the amounts of CaZrO3 in the resultant powders increased with aconcomitant decrease in CaCO3 and ZrO2 contents. After washing with hot-distilled water, the samples containing nano- and micro-ZrO2 heated for 3 h at 800 oC and 1000 oC, were single-phase CaZrO3 with 70–90 nm and 400–450 nm particle size, respectively. 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.