加压辅助闪烧工艺制备四方相氧化锆

研究了加压辅助闪烧烧结工艺参数(温度、电压、电流、压力)对钇稳氧化锆致密度、微观组织结构和成分组成的影响,该工艺在热压烧结基础上叠加闪烧效应,利用高电场强度使高温导电氧化锆瞬间发生密实化烧结。结果表明:钇稳氧化锆的闪烧临界温度为880℃,在相同的电场强度条件下,闪烧临界温度处烧结可获得最大的闪烧收缩量。氧化锆在临界烧结温度下瞬时放电快速烧结符合焦耳热效应和接触点局部热效应,临界闪烧温度的高峰值功率闪烧易导致样品的组织结构和成分变化,峰值功率应进行控制,即电流强度应低于3 A。

Pressure-assisted Flash Sintering Processing of Tetragonal Zirconia Ceramics

A pressure rapid sintering process of tetragonal zirconia ceramics was proposed. The effects of sintering parameters(i.e., temperature, voltage, current and pressure) on the density, microstructure and phase composition of zirconia were investigated. The process superimposed a flash burning effect based on hot pressing sintering, and the high-temperature conductive zirconia was instantly densified and sintered at a high electric field strength. The results show that the pressure-assisted flash sintering process involves the advantages of hot pressing sintering and flash sintering. Zirconia powder was used as a raw material to simplify the green pressing process. Low temperature and instantaneous flash firing inhibit the high-temperature phase transformation of zirconia. Hot pressing in sintering process ensures the diffusion and flow of zirconia powder and enhances the density.