Effects of Additives on Phase Composition, Microstructure, and Properties of Zirconia Products Fired at Different Temperatures

摘要

The calcia-stabilized zirconia grains with different sizes and the calcia-stabilized zirconia powder were used as main starting materials,m-ZrO2 micropowder and Y2O3 powder as additives,and sulphite liquor as binder. The specimens with the dimension of 50 mm×50 mm were prepared under 150 MPa,dried at 110 ℃ for 24 h,then fired at 1 700 ℃ and 1 750 ℃ in air,respectively. The phase composition,microstructure and properties of specimens were analyzed with XRD,SEM,and other test methods. The results indicate that:(1) the appropriate amount of m-ZrO2 micropowder and Y2O3 powder can promote the sintering property of calcia-stabilized zirconia products,and the sintering property is better when m-ZrO2 micropowder addition in matrix is 5%-10% and Y2O3 powder addition in matrix is 1%; (2) the main phase compositions of zirconia products fired at 1 700 ℃ are c-ZrO2 and m-ZrO2,no t-ZrO2 is found; (3) the microstructure of the specimen containing additives is obviously different with the specimen without additives after firing at 1 700 ℃. The matrix grains rearrange and grow in the specimens containing additives forming permeable network gas pore,and the process of the grain growth helps the gas release during sintering. So the relative density is bigger in fired specimens containing an appropriate amount of additives.