Effects of sintering process, pH and temperature on chemical durability of Ce0.5Pr0.5PO4 ceramics

The Ce0.5Pr0.5PO4 ceramics with high relative density of 99% and small average grain size of 0.15 μm were prepared by hot-pressing at 1150 °C for 2 h. The effects of sintering process, pH values and temperature on the chemical durability of the ceramics were investigated. The results show that normalized elemental leaching rates of Pr (LRPr) and Ce (LRCe) of the hot-pressed ceramics are slightly lower than that of the ceramics sintered at 1500 °C for 4 h by normal pressure. The LRPr and LRCe reach the highest values (∼10−3 g m−2 d−1) when pH = 3, while the LRPr and LRCe have the lowest values (∼10−7 g m−2 d−1) when pH = 7. The surface of the ceramic in pH = 3 leachate appears serious corrosion with plenty of pores. The precipitation of low-soluble was formed on sample surface during leaching tests at pH = 9 and 11.