Y-TZP纳米陶瓷的制备、结构及力学性能

采用沉淀法制备的Y-TZP纳米粉体经冷压成型后烧结成Y-TZP纳米陶瓷.结果表明,Y-TZP纳米陶瓷的密度随着烧结温度的升高和烧结时间的延长而增大,但随成型压力和初始粉体颗粒的增大而减小.而陶瓷平均晶粒尺寸随成型压力的增大和烧结时间延长而长大.烧结过程中大量单斜相ZrO2生成改变了Y-TZP纳米陶瓷的烧结行为和微结构.采用无压烧结获得了相对密度为98%、平均晶粒尺寸为60 nm的Y-TZP纳米陶瓷.Y-TZP纳米陶瓷的显微硬度主要取决于陶瓷的相对密度、相结构和晶粒尺寸,即陶瓷的四方相质量分数越高,相对密度越大,晶粒尺寸越小,则显微硬度越高.

Preparation, microstructures and mechanical properties of Y-TZP nanoceramics

Y-TZP nanoceramics were prepared by means of sintering after their cold-press formation of the Y-TZP nanopowders prepared with co-precipitation method.The result showed that the relative density of the Y-TZP nanoceramics increased with sintering temperature and time,whereas decreased with the original mean particle size of the Y-TZP nanopowders and formation pressure.The average grain sizes of the Y-TZP nanoceramics increased,however,with the sintering time and formation pressure.The generation of a great amount of tetragonal-monoclinic phase transformation of ZrO2 during the sintering process altered the sintering behavior and microstructure of the Y-TZP nanoceramics.The Y-TZP nanoceramics with an average grain size of 60 nm and a relative density of 98% were prepared by pressureless sintering.The Vickers microhardness of the Y-TZP nanoceramics was mainly related to the relative density,phase composition,and average grain size of the Y-TZP nanoceramics.Namely,the Vickers microhardness increased with the content of the tetragonal phase and relative density,and inversely with the average grain size.