(Y,Mg)-PSZ材料的微晶化设计、制备与表征

Design,Preparation and Characteristics of Fine-Grained (Y,Mg)-PSZ Ceramics

通过化学包裹-共沉淀工艺制备MgO,Y2O3复合稳定、硬质相颗粒(Al2O3,MgAl2O4)均匀包裹的氧化锆基超细陶瓷粉体。经干压、等静压成型,在小于或等于1550℃下烧结致密并实现了PSZ材料的微晶化。借助XRD,SEM,TEM,EDAX等手段研究了材料的微观结构、物相组成与宏观力学性能间的关系,结果表明:(1)通过MgO,Y2O3的复合稳定和硬质相颗粒相(Al2O3,MgAl2O4)的晶界钉扎,在较低烧结温度(小于或等于1550℃)下制备了复相PSZ陶瓷,晶粒尺寸控制在10μm左右;(2)经1100℃下适时热处理,所制备的复相PSZ陶瓷表现出PSZ增韧材料所特有的优良力学性能和结构特征;(3)引入Al2O3,MgAl2O4等硬质颗粒相,即细化晶粒、强化晶界的同时,又利用其颗粒增韧和微裂纹增韧等机制以提高材料的中、高温力学性能。

The ZrO2-based ceramics powders,which was stabilized by MgO and Y2O3 and added rigid particles(Al2O3,MgAl2O4),were prepared by particles-coated and coprecipitation process. Green bodies were formed by uniaxial pressing,followed by cold isostatic pressing,then were sintered at 1550℃,fine-grained (Y,Mg)-PSZ ceramics were synthesized with high density. Analysis technics,such as XRD,SEM,TEM,EDAX were adopted in the paper,the results revealed the effect of microstructures and phase compositions on mechanical properties for prepared PSZ materials. Firstly,by means of co-stabilization of MgO and Y2O3,and rigid particles additions on the PSZ grain boundary,fine-grained PSZ materials were prepared with grain size less than 10μm.Secondly,annealed at 1100℃ for appropriate time,the mechanical properties of fine-grained PSZ ceramics were improved,and the microstructure characteristics were obviously developed. Thirdly,rigid particles such as Al2O3 and MgAl2O4 added in PSZ ceramics materials not only made grain size thinner and strengthen the grain boundary,but also contributed to better mechanical properties at 800℃ owing to the coordinated effect of particle toughening and microcrack toughening,instead of invalidation effect of stress-induced transformation toughening above 800℃