The Calcination Reaction Process and Phase Characterization of ZrO_2-Al_2O_3-CeO_2 Powders Prepared by Co-precipitation Method

The composite precursor powders of ZrO_2-Al_2O_3,Al_2O_3-CeO_2,ZrO_2-CeO_2 and ZrO_2-Al_2O_3-CeO_2 system are respectively prepared with a fixed proportion by co-precipitation method,using ammonia as precipitant. Thermal behaviors of these precursor powders are investigated by the differential thermal analysis and thermogravime- try(DTA-TG).The phase identifications after calcined at different temperatures are characterized by X-ray diffractom- etry(XRD).The results reveal that ZrO_2 and CeO_2 are prior to forming Ce-Zr solid solution and no chemical reactions happen between CeO_2 and Al_2O_3 up to 1300℃.The crystallization temperature of cubic Zr-Ce solid solution rises due to the existence of Al_2O_3 and tetragonal Zr-Ce solid solution can be retained at room temperature after calcination at 1300℃.