2种Y-TZP/Al_2O_3陶瓷材料的结构和磨料磨损性能比较研究

Comparative Study of Microstructures and Abrasive Wear-resistance of Two Y-TZP/Al_2O_3 Ceramics

基于化学共沉淀法和机械混合法2种引入Y2O3的不同方式,通过等静压成型和常压高温烧结制备了2种Al2O3增强Y-TZP陶瓷材料(Y-TZP/Al2O3);用X射衍射仪分析了2种材料的物相组成;对比考察了2种陶瓷材料试样的磨料磨损性能,并用扫描电子显微镜观察分析了2种材料试样的磨损表面形貌.结果表明:基于化学共沉淀法引入Y2O3制备的陶瓷材料的结构均匀、晶粒细小,且耐磨性较好;当2种Y-TZP/Al2O3陶瓷材料的HV和KIC相近时,其磨料磨损性能明显同其晶粒尺寸和微结构相关;2种材料的磨料磨损机理亦存在明显差异,基于化学共沉淀法引入Y2O3而制备的Y-TZP/Al2O3陶瓷材料主要呈现微裂纹和微犁削特征,基于机械混合法引入Y2O3而制备的Y-TZP/Al2O3陶瓷材料主要呈脆性断裂特征.

Two kinds of yttriadoped tetragonal zirconia polycrystal ceramics reinforced with alumina (abridged as YTZP/Al2O3) were prepared by means of isostatic pressing and sintering at ambient pressure and high temperature, using chemically coprecipitated (The corresponding ceramic specimen was coded as CYZA) and mechanically mixed Y2O3 (The corresponding ceramic specimen was coded as MYZA) as the stabilizing ingredient. The microstructures and phase compositions of the resulting YTZP/Al2O3 specimens were analyzed by means of scanning electron microscopy and Xray diffraction. The abrasive wearresistance of the ceramic specimens sliding against a rubber counterpart in the presence of aqueous NaOH solution containing SiO2 as the abrasive medium was examined in a blockondisc configuration. The worn surface morphologies of the ceramic specimens were observed with a scanning electron microscope. The results indicated that the CYZA specimen had uniform structure and fine grain size, which accounted for its better abrasive wearresistance than the MYZA specimen with nonuniform structure and largely different grain sizes. The CYZA specimen was characterized by microcracking and microploughing, while the MYZA dominated by brittle fracturing. Such differences in the worn surface morphologies of the two kinds of YTZP/Al2O3 specimens were also attributed to their different microstructures and grain sizes.