本文围绕制备高耐压、高可靠的宽温稳定型贱金属内电极多层陶瓷电容器（BME-MLCC）这一目标，以(BaCa)TiO3（BCT）介质材料为研究对象，通过成分设计、缺陷控制、界面调控等研究手段，制备出有优异介电性能、高使用温度、高耐压特性及高可靠性的BCT基介质材料，并初步开发相应的BME-MLCC器件，为高端MLCC制备及应用提供理论支撑和实际指导。首先，研究了稀土掺杂改性的BCT基介质材料的结构与性能。通过Yb稀土元素掺杂改性，发现由于受主掺杂引起的晶格失配，导致晶粒内部内应力的变化，进而改善BCT基介质材料居里温度，得到了最高使用温度满足150℃的X8R高温稳定型介质材料。分别研究了Dy/Ho和Y/Yb双稀土元素掺杂改性的机制，通过调整A/B位元素的占比和控制缺陷的形成，使介温曲线趋于平缓，得到室温相对介电常数大于2300的BCT基高介电常数介质材料。采用Y/Ho双稀土元素掺杂，通过控制缺陷以减少介质材料在还原气氛烧结时产生的大量氧空位，得到的介质材料电容变化率在40kV/cm电场强度下仅为-28%，具有优异的偏压特性和可靠性。介质材料的改性研究为制备耐高压、高可靠的BME-MLCC提供良好的理论基础。系统研究了BaSiO3和SiO2烧结助剂对BCT基介质材料性能调控的作用机制。合适的助烧剂含量不仅有效降低了介质材料的烧结温度，保证在制备电容器阶段与内电极实现共烧匹配，并且通过优化介质材料“芯壳结构”和界面效应，改善了介质材料的介温稳定性和偏压特性。初步开发出静电容量10μF，额定电压100V的X8S宽温型BCT基BME-MLCC，与目前仅有的由日本生产的同型号高端MLCC对比，具有相似的电学性能以及更宽的温度使用范围，为推进高耐压、高可靠型BME-MLCC的国产化生产意义重大。针对BME-MLCC介质-内电极匹配共烧问题，研究发现通过提升烧结段的升温速率和采用两段式烧结可以有效改善电极连续性。针对不同型号的BME-MLCC设计了再氧化工艺，结合器件的微结构以及阻抗图谱、漏电流测试、加速老化测试等研究分析，证明了合适的再氧化工艺可以有效的减少BME-MLCC中氧空位浓度并提升其可靠性，为实际的工业生产提供了科学指导。关键词：(BaCa)TiO3；多层陶瓷电容器；温度稳定性；偏压特性；可靠性

Focusing on the goal of preparing high-voltage, high-reliability, and high-temperature stability base-metal inner electrode multilayer ceramic capacitors (BME-MLCC), this dissertation takes (BaCa)TiO3 (BCT) dielectric materials as the research object, through composition design, defect control, interface control, and other research methods, prepared BCT-based dielectric materials with excellent dielectric properties, high operating temperature, high-withstand voltage, and high-reliability, and initially developed the corresponding BME-MLCC devices. In addition, it provides theoretical support and practical guidance for the preparation and application of high-end MLCCs.Firstly, the microstructures and properties of rare-earth elements doping-modified BCT-based dielectric materials were studied. Through the doping modification of Yb, it was found that the lattice mismatch caused by the acceptor doping led to the change of the internal stress of the grain and then improved the Curie temperature of the BCT-based dielectric material, and obtained a high-temperature stable X8R-type dielectric material with a maximum working temperature of 150°C. The mechanism of double rare earth elements doping modification of Dy/Ho and Y/Yb was studied separately. By adjusting the proportion of A/B elements and controlling the formation of defects, the curve of temperature dependence of dielectric constants tended to be gentle, and the room temperature relative dielectric constant was greater than 2300. Doping with Y/Ho double rare earth elements, by controlling the defects to reduce a large number of oxygen vacancies generated when the dielectric material is sintered in a reducing atmosphere, the capacitance change rate of the obtained dielectric material is only -28% under the electric field strength of 40kV/cm, which exhibits excellent bias characteristics and reliability. The research on the modification of dielectric materials provides an excellent theoretical basis for the preparation of BME-MLCCs with high voltage resistance and high reliability.The mechanisms of BaSiO3 and SiO2 sintering aids on the performance regulation of BCT-based dielectric materials were systematically studied. Selecting appropriate content of sintering aids not only effectively reduces the sintering temperature of the dielectric material to ensure the co-fire matching with the internal electrodes in the capacitor preparation stage, but also improves the dielectric properties of the dielectric material by optimizing the "core-shell structure" and interface effects.Preliminary develop the X8S-type BCT-based BME-MLCC with an electrostatic capacity of 10μF and a rated voltage of 100V. Compared with the only high-end MLCC of the same type produced in Japan, it has similar electrical properties and a wider temperature range usage. It is of great significance to promote the localized production of high-voltage resistant and high-reliability BME-MLCC. Aiming at the co-firing problem of matching the BME-MLCC dielectric layers and internal electrodes, the study found that the continuity of inner-electrode can be effectively improved by increasing the heating rate of the sintering section and adopting the two-step sintering method.A comprehensive design of the reoxidation process for different types of BME-MLCCs was investigated. Combined with the research and analysis of the microstructure, impedance spectrum, leakage current test, highly-accelerated lifetime test, etc., a suitable reoxidation process can effectively reduce oxygen vacancy concentration of the BME-MLCC and improve its reliability, which provides scientific guidance for industrial process.Keywords: (BaCa)TiO3; multilayer ceramic capacitors; temperature stability; DC-bias; reliability