作　　者： ; ;

机构地区： 哈尔滨工业大学

出　　处： 《硅酸盐学报》 1994年第1期22-28,共7页

摘　　要： 用热膨胀分析、Ｘ射线衍射研究了热压２％（ｍｏｌ）Ｙ＿２Ｏ＿３－ＺｒＯ＿２陶瓷中ｔ－ｍ等温转变动力学。结果表明：经过快速冷却而得到的四方相（ｔ）在随后２００～４００℃区间保温时发生了四方相（ｔ）到单斜相（ｍ）的转变。该转变的时间－温度－转变量（ＴＴＴ）曲线呈Ｃ形，鼻子温度为３００℃。高于或低于上述温度范围，未出现ｍ相，可用Ａｖｒａｍｉ方程的一般形式来描述动力学曲线。该相变的形核与长大均是时间的函数，相变激活能为２８．６７ｋＪ／ｍｏｌ。ｔ相的亚稳性不仅与稳定剂分布及晶粒尺寸有关，而且还受冷却速度所控制。 The kinetics of isothermal transfomation from tetragonal(t)to monoclinic(m)structure in zirconiastabilized with 2%(mol)yttria was systematically studied by using thermal expansion analysis(TEM),electronprobe microscopy analysis(EPMA ),X-ray diffractometer(XRD )and transmission electron microscopy(TEM). Results show that t phase obtained in rapid cooling transforms isothermally to m phase in a constanttemperature range from 200～ 400 ℃ for 4 hours. The time-temperature-transformation(TTT) curve is charac-terized by its C-shape with a nose temperature of 300℃. A small amount of m phase can be detected when theconstant temperature is beyond the above mentioned temperature range,The isothermal transformation kineticscan be expressed in terms of Avrami equation in which the nucleation and growth of new phase are both thefunction of time with activation energy determined to be 28. 67kJ/mol. Metastability of t phase is controlled bvthe cooling rate,content of stabilizer as well as the grain size. In-situ observation of m phase propagation inducedby electron beam reveals that the t→m transformation is related to diffusion.

关 键 词： 等温转变 氧化锆陶瓷 氧化钇

领　　域： [化学工程] [化学工程]