新型ZnO陶瓷线性电阻材料

New Type ZnO Ohmic Ceramic Materials

本文研究了少量ＭｇＯ、Ｌａ２Ｏ３、ＺｒＯ２等对ＺｎＯ陶瓷线性电阻材料晶粒生长速度和最终晶粒尺寸的影响规律，以及极微量掺杂Ｌｉ２Ｏ对晶粒和晶界电阻率的影响规律，实验表明，ＭｇＯ、Ｌａ２Ｏ３，和ＺｒＯ２都能使ＺｎＯ陶瓷伏安特性线性化；在一定添加量范围内，ＭｇＯ的添加量不影响陶瓷线性电阻的电阻率，Ｌａ２Ｏ３和ＺｒＯ２的添加量都能有效地控制陶瓷线性电阻的电阻率；ＭｇＯ的添加量不影响ＺｎＯ陶瓷的晶粒生长速度，Ｌａ２Ｏ３和ＺｒＯ２降低晶粒生长速度。从杂质缺陷的生成、扩散及其对ＺｎＯ晶粒本征缺陷的影响作用等角度，分析讨论了添加剂对晶粒生长的影响规律，认为添加剂通过改变烧结过程中ＺｎＯ晶粒自由电子浓度，进而改变填隙锌离子浓度［Ｚｎｉ］，从而控制ＺｎＯ晶粒生长速度。

In this paper,effects of MgO,La2O3and ZrO2 additives on grain growth rate and final grain size,and influences of trace Li2O on resistivities of ZnO grain and intergranular layer of ZnO ohmic ceramic materials were investigated.The experimental results indicate that MgO,La2O3 and ZrO2 can all make voltage-current characteristic of ZnO ceramic linear,MgO doesn't influence ceramic resistivity,La2O3 and ZrO2 can be effectively used to control ceramic resistivity,MgO doesn't affect growth rate of ZnO grains,while La2O3 and ZrO2lower grain growth rate. Based on formation and diffusion of impurity defects and their influences on intrinsic defects of ZnO grains,the experimental results have been analysed.It is thought that additives can change the concentration of interstitial zinc[Zni],and finally control the growth rate of ZnO grains through changing the concentration of free electrons of ZnO grain during sintering.