The Synthesis Of ZrO₂（Y₂O₃） Ceramic Material By The High-temperature Mechanochemical Method

Yttria-stabilized-zirconia ceramic is one kind of important high-temperature oxide ceramic material,which has been widely applied in the field of aerospace because of excellent mechanical properties,chemical corrosion resistance and high temperature stability.In this thesis,yttria-stabilized tetragonal zirconia ceramic materials powders are synthesized by chemical co-precipitation method combined with high-temperature mechanochemical method and characterized by X-ray diffraction（XRD）and scanning electron microscopy（SEM）,etc.Some discussion have been conducted in the preparation process.Thesis research achievements are as follows:（1）The 5 mol%Y₂O₃-ZrO₂ precursors were synthesised by co-precipitation method with Zirconium oxychloride and Yttria as raw materials.According to the differential scanning calorimetry/thermogravimetry analysis（DSC-TGA）curves,the reasonable calcination temperature of powders was comfirmed.Then,the effects on the physical properties of products of the experimental conditions was discussed,such as the reactant concentration,the solution pH and the reaction temperature.The results showed that the better properties Y₂O₃-ZrO₂ powders,which have small average particle size,well-distributed particle size and good dispersion,is prepared under the condition of 0.1 mol/L,60 ℃,pH=9 at high milling temperature.（2）The Y₂O₃-ZrO₂ powders were also prepared with high-temperature mechanochemical method by the precursors of chemical co-precipitation preparation as raw materials.ZrO₂ powders were synthesized by changing the ball milling temperature,the ball milling time and Y₂O₃ doping amount.Experimental results showed the better preparation process of ZrO₂ powders,which have small average particle size,well-distributed particle size and good dispersion,is under the condition of 600℃,5 h.（3）Comparing to traditional high-temperature solid state reaction and chemical method,we can get a conclusion that chemical co-precipitation method combined with high-temperature mechanochemical method is not only capable to synthesize tetragonal zirconia powders with simple preparation techniques and in low temperature which have small average particle size,well-distributed particle size and good dispersion,but also increase the solid solubility of Y₂O₃ doping in ZrO₂.