水基流延片式ZnO压敏电阻器低温共烧工艺及其性能

Low-Temperature Co-Firing Preparation and Properties of ZnO Chip Varistor by Aqueous Tape Casting

用环境扫描电子显微镜(ESEM)、X射线衍射(XRD)和X射线能谱(EDXS)等研究了水基流延片式ZnO压敏电阻器的低温共烧工艺及其对微观结构和电学性能的影响规律。ESEM分析结果表明:当等静压压力为60 MPa时,Ag电极与流延膜生坯界面结合紧密,Ag电极分布连续,900℃共烧时,未出现开裂、分层,两者收缩率接近。EDXS和XRD分析结果表明:900℃共烧时,Ag在片式压敏电阻器中以单质形式存在,流延膜与Ag电极化学兼容性良好,且在共烧界面处未发现有明显的Ag离子扩散。该流延膜可以与Ag电极在900℃时实现低温共烧,用此制备的片式ZnO压敏电阻器具有良好的压敏性能:压敏电压V1mA=6.1 V,非线性系数α=28.1,漏电流IL=0.15μA。

Effect of low-temperature co-firing preparation on the microstructure and electrical properties of ZnO chip varistor pre-pared using an aqueous tape casting was investigated by environmental scanning electron microscopy（ESEM）,X-ray diffraction（XRD） and energy dispersive X-ray spectroscopy（EDXS）.The ESEM results show that ZnO varistor sheets and Ag pastes contact with each other compactly under an isostatic pressures of 60 MPa.Ag electrode was distributed continuously and not delaminated with ZnO varistor sheets when co-fired at 900 ℃.The EDXS and XRD results reveal that Ag electrode remains the state of single matter in ZnO chip varistor when sintered at 900 ℃.There was no chemical reaction and interfacial diffusion occurred between Ag electrode and ZnO varistor sheets at the interface of ZnO chip varistor.ZnO varistor sheets by aqueous tape casting could be co-fired with Ag electrode at 900 ℃.The excellent electrical properties of ZnO chip varistor were obtained as follows： Breakdown voltage V1mA = 6.1 V,nonlinear coefficient α = 28.1,and leakage current IL = 0.15 μA.