【作者】 李姣红；

【导师】 牟国栋；

【作者基本信息】 西安科技大学 ， 材料学， 2011， 硕士

【摘要】 本文以制备低压ZnO压敏陶瓷材料为目的,论述了低压ZnO压敏陶瓷的性能、用途、分类、实现低压化的方法、国内外的研究动态及发展趋势;研究了制备低压ZnO压敏陶瓷的基本工艺和方法,包括压制成型时的压强和粘结剂用量的选择;研究了烧结工艺中烧结温度、保温时间及升温速率对低压ZnO压敏陶瓷电性能和致密度的影响规律,优化了低压ZnO压敏陶瓷的烧结工艺。研究结果表明:坯体的成型极限压强为20Mpa、粘结剂加入量为12wt%时低压ZnO压敏陶瓷的各项性能最优;低压ZnO压敏陶瓷的最佳的烧成工艺条件为:烧成温度1200℃,保温时间2h,升温速率7℃/min。本文首次采用正交试验法,利用制备ZnO压敏陶瓷的常规工艺,系统研究了Bi、Ti、Co、Mn、Sn、Sb等6种元素氧化物对ZnO压敏陶瓷性能的影响,得出低压ZnO压敏陶瓷的最佳配方为:1.25%Bi₂O₃+0.4%TiO₂+0.4%Co₂O₃+1%MnO₂+1%SnO₂+1%Sb₂O₃ +94.95%ZnO。在最佳烧结工艺条件下烧结,压敏电压为10.15V,漏电流为2.05μA,非线性系数为22.2。在低压配方的基础上,通过添加稀土元素氧化物Y₂O₃做了改性试验,研究了Y₂O₃掺杂对低压ZnO压敏陶瓷电性能的影响规律及作用机制。研究发现:Y₂O₃的加入能使低压ZnO压敏陶瓷的非线性系数增大,漏电流相应的减小,但同时会使压敏电压大幅度提高,同时,Y₂O₃的掺杂会使低压ZnO压敏陶瓷的晶粒尺寸明显减小,并且大小和分布更为均匀。更多还原

【Abstract】 In this paper, low-voltage ZnO varistor ceramics were comprehensively analyzed. Properties, application,classification,method of low-voltage,studying situation and developing trend of low-voltage ZnO varistor ceramics were also discussed. The techniques and methods of low-voltage ZnO varistor ceramics were studied;The influence of forming pressure and agglomerant dosage in the forming process on properties of low-voltage ZnO varistor ceramics were researched too; The influence of sintering temperature,holding time and heating rate on the electrical properties and density of low-voltage ZnO varistor ceramics were also investigated. The sintering process of low-voltage ZnO varistors were optimized.The results show that forming limited pressure is 20Mpa and agglomerant dosages is 12wt%,the properties of low-voltage ZnO varistors is optimum; It can obtain the best conditions for sintering process when sintering temperature is 1200℃,holding time is 2 hours and heating rate is 7℃/min.Unlike conventional test method,this paper is first studied through the orthogonal test.According to the kinds of additives in low-voltage ZnO varistor ceramics,the effects of elements oxide Bi,Ti,Co,Mn,Sn,Sb on the characteristics of low-voltage ZnO varistor ceramics were studied respectively with the conventional processing of ZnO varistor ceramics. Finally, the optimum composition of low-voltage ZnO varistor is: 1.25%Bi₂O₃+0.4%TiO₂+ 0.4%Co₂O₃+1%MnO₂+1%SnO₂+1%Sb₂O₃+94.95%ZnO.The good characteristic with V1mA= 10.15V, IL= 2.05μA, =22.5 could be got at the proper sintering process.The influence of Y₂O₃ is used as additives on the electrical properties and mechanism of low-voltage ZnO varistor ceramics were studied.The results show that the addition of Y₂O₃ can increase the nonlinear coefficient of low-voltage ZnO varistors and decrease the leakage current,and at the same time improve the varistor voltage greatly.In addition,doping Y₂O₃ can reduce the size of ZnO grain evidently and make the grain size and distribution more uniform.更多还原