Co、Mn、Cr等掺杂ZnO陶瓷合成电磁性能.docVIP

Co、Mn、Cr等掺杂ZnO陶瓷的合成及电磁性能 采用低温固相化学法合成掺杂ZnO粉体，并用这种粉体在不同温度下烧结制备了ZnO压敏电阻。借助XRD、SEM、TEM、BET等检测手段对粉体产物的性能进行了表征，采用XRD、SEM等手段对ZnO压敏陶瓷的物相、结构进行了分析，并对这种方法制备的粉体及压敏电阻的性能进行了研究。而且研究了不同浓度Cr、Co和Mn的掺杂对ZnO-PbO-B2O3陶瓷压敏特性的影响。实验表明，ZnO平均晶粒尺寸随各元素掺杂量增加而逐渐变大，压敏电压也随之升高，非线性系数随各元素掺杂量增加而先增大后减小，漏电流先减小后增大。分析认为，过渡族金属元素掺杂对ZnO压敏材料电性能的影响不仅与电子的能级有关，与其自旋特性也紧密相连。ZnO中掺杂的Cr、Mn、Co元素随机取代其中的部分Zn原子后，Cr2+、Mn2+、C02+在ZnO中产生局域磁矩，会对与其取向不同的自旋电子产生强的散射，这样可增大ZnO陶瓷电阻率和提高其非线性特性。 关键词：压敏材料，电性能，过渡元素，低温固相化学法，压敏电阻 Abstract The powders of doped ZnO were synthesized by the solid-state reaction at a low temperature.Then the ZnO varistors were prepared at different sintering temperatures. The properties of the powders were characterized by means of XRD,SEM,TEM and BET,and the composition, microstructure of ZnO varistors were determined by XRD and SEM.And The effects of amount of Cr,Co and Mn doping on the current-voltage characteristics of ZnO-PbO-B203 varistor are summarized．It was found that the average grain size of ZnO and the breakdown voltage gradient increased with the increase of the concentration of C0203,Mn02 and Cr203,the nonlinearity coefficients will be greatly increased and then decreased，but leakage current density decreased and then increased．The current-voltage characteristics of ZnO decided by the electronic energy level structure，and associated with electronic spin of transition metal elements．Portion of Zn in ZnO crystal randomly substituted by Mn,Cr or Co elements,gave rise to localized magnetic moments and the highly scattering to electronics with different spin orientation,favorable for increasing the resistivity and nonlinear characteristics of ZnO varistor. Key words：vailstor；electrical properties；transition-metal elements；solid-state reaction at a low temperature; doped ZnO powders varistor 1、前言 ZnO是一种原料丰富,用途极广的材料。很早以前,人们就将它用于医药、化妆品、颜料、印刷等工业。特别是近十多年来,利用少量添加物改性ZnO陶瓷,使其具有半导性、光导性、压电性。并利用多晶陶瓷的界面特性,制作了具有高非线性伏一安特性的过电压浪涌吸收器；灵敏度高,选择性好的气体传感器；电子照像感光剂；触媒剂以及压电薄膜换能器。ZnO作为一种新的功能材料已占有相当重要的地位。 ZnO的特性以及相应的应用,与添加物和制备工艺