【作者】 唐俊；

【导师】 涂铭旌；

【作者基本信息】 四川大学 ， 材料学， 2003， 硕士

【摘要】 本文研究了稀土氧化物Nd₂O₃、CeO₂、La₂O₃对氧化锌压敏阀片主要电性能的影响规律及作用机制。 在传统配方的氧化锌压敏阀片原料中添加微量稀土氧化物Nd₂O₃、CeO₂、La₂O₃，研究各种稀土氧化物的添加量对氧化锌压敏阀片主要电性能的影响规律，优化氧化锌压敏阀片原料中各种稀土氧化物添加剂的成分。研究结果表明：微量的稀土氧化物在基本不影响压比的前提下能够显著提高氧化锌压敏阀片的电位梯度，减小漏电流。当Nd₂O₃含量为0.04mol％时，氧化锌压敏阀片的电位梯度达到极值，与不含Nd₂O₃的氧化锌压敏阀片相比提高约65％，且压比最低，漏电流最小，因此本实验Nd₂O₃添加量的最佳值为0.04mol％。当CeO₂含量为0.06mol％时，氧化锌压敏阀片的电位梯度达到极值，比添加CeO₂前的电位梯度提高约30％，且压比较低，漏电流最小，因此本实验CeO₂添加量的最佳值为0.06mol％。当La₂O₃含量为0.04mol％时，氧化锌压敏阀片的电位梯度达到极值，与不含La₂O₃的氧化锌压敏阀片相比提高约57％，且压比较小，漏电流最低。因此本实验La₂O₃添加量的最佳值为0.04mol％。综合分析，Nd₂O₃提高压敏电位梯度的作用最为显著，La₂O₃次之，CeO₂最弱，并且适量的Nd₂O₃在显著提高压敏电位梯度的同时，可降低漏电流和压比，使压敏阀片具有优良的综合性能。 通过扫描电镜（SEM）、电子能谱仪（EPD）、X射线衍射仪（XRD）、显微图像分析系统进行显微组织结构分析后发现，添加微量稀土氧化物Nd₂O₃、CeO₂、La₂O₃使晶粒尺寸减小，原因在于含稀土元素的相-以原相形式独立存在的CeO₂和La₂O₃相、以及含Nd的新相Na₂Nd₂Sb₂(Zn₂AlO₁₂)，钉扎在晶界，形成晶界电阻 四川大学硕士学位论文层，与尖晶石相协同作用，阻碍晶界运动，减小氧化锌晶粒尺寸，使晶粒分布均匀致密。另外添加剂CeOZ和LaZ仇能够通过改变烧结过程中氧化锌晶粒的自由电子浓度，来改变填隙锌离子浓度〔Zni〕，从而控制氧化锌晶粒生长速度，提高电位梯度。添加微量稀土氧化物通过增大势垒高度和氧化锌晶粒电阻率来减小泄漏电流。 总之，添加微量稀土氧化物能够显著提高氧化锌压敏阀片的电位梯度、降低漏电流，使其具有优良的综合性能。更多还原

【Abstract】 The influences and mechanisms of rare-earths oxide additives La2O3 on the electrical performance of zinc oxide varistor were explored in this paper.Microadded rare-earths oxide in traditional raw materials of zinc oxide varistor, researched the influences of rare-earths oxide on the electrical performance of zinc oxide varistor , and selected the optium composition of various rare-earths oxide additives. The results of experiment indicated that adding a appropriate amount of rare-earths oxide in zinc oxide varistor led to increase potential gradient greatly, decrease leakage current with voltage ratio no changed. When the Nd2O3 content is 0.04mol%, potential gradient of zinc oxide varistor is maximum, improves about 65% compared with zinc oxide varistor no containing Nd2O3, voltage ratio and leakage current are the lowest. So the optium content of Nd203 is 0.04mol% in this study. When the CeO2 content is 0.06mol%, potential gradient is maximum, improves about 30%, voltage ratio is lower, and leakage current is the lowest. So the optium content of CeO2 is 0.06mol% in this study. When the La2O3 content is 0.04mol%, potential gradient is the highest, and improves about 57%, voltage ratio is lower, leakage current is minmum. So the optium content of La2O3 is 0.04mol% in this study. Synthetic analyze that effect of Nd2O3 on improving potential gradient is the most outstanding, effect of La2O3 is more outstanding and that of CeO2 is theinferior. Adding appropriate amout Nd2O3 improves remarkably potential gradient, at the same time decrease leakage current and voltage ratio, that results in zinc oxide varistor with excellent comprehensively performance.Microstruture of zinc oxide varistor was researed with the help of scanning electronic microscope(SEM), energy spectrum apparatus(EPD), X-ray diffraction(XRD), and microscopic image analyzing system. It is suggested that microadding rare-earths oxide Nd2O3,CeO2,La2O3 can reduce the grain size because the phases containing rare-earths element-both CeO2, La2O3, which are independent phases, and the new phase Na2Nd2Sb2(Zn2AlO12) containing neodymium all lie in the grain boundary, form the intergranular resistance layers with Zn2.33Sb0.67O4, hinder the movement of grain boundary, make growth rate of zinc oxide varistor grain slow during sintering, which reduce the grain size and make the grain well-distributed. Moreover, CeO2 and La2O3 can change the concentration of interstitial zinc [zni], and finally control growth rate of zinc oxide varistor grain, improve potential gradient through changing the concentration of free electrons of zinc oxide grain during sintering. Microadding a appropriate amount of rare-earths oxide can decrease leakage current by means of raising the height of barrier potential and increasing grain resistivity of zinc oxide.In short, adding appropriate amount rare-earths oxide can improve potential gradient greatly, decrease leakage current with voltage ratio no changed and make zinc oxide varistor with outstanding comprehensively performance.更多还原