基于CaO-Al2O3辅助电极的熔融金属硫传感器的激光熔覆制备

熔融金属硫传感器对于实现生产过程自动化控制，提高生产效率和产品质量具有重要作用。针对目前固体电化学硫传感器在材料制备和烧结过程中存在的化学成分易氧化和分解等问题，本项目在理论研究和前期实验的基础上，拟采用激光熔覆技术在氧化锆质固体电解质表面制备CaO-Al2O3辅助电极，研究CaO-Al2O3材料组成和激光熔覆过程对辅助电极组织结构、与固体电解质基材间的结合强度以及与熔融金属中[S]组分间反应性能的影响规律和作用机理；建立氧、硫扩散的微观模型和熔融金属硫传感器理论方程，确定CaO-Al2O3材料制备和辅助电极激光熔覆最佳工艺，阐明辅助电极的形成机理和结构模型以及固体电解质基材与辅助电极间的结合机理和抗热震机理，建立电极反应动力学方程，探讨硫组分原位反应和界面扩散过程；揭示熔融金属温度和元素含量对硫传感器性能指标的影响规律和作用机理，为研制高性能熔融金属硫传感器及确定其使用条件提供理论依据。

The sulfur sensor for application in molten metal plays an important role in realizing the automatic control of the production process, improving the production efficiency and increasing the quality of metallurgical products. In view of the shortcomings existing in the preparation and sintering process of the solid electrochemical sulfur sensor, such as the chemical composition is easy to be oxidized and decomposed, on the basis of the theoretical research and previous experimental , in this project a CaO-Al2O3 auxiliary electrode will be prepared on the surface of the zirconia solid electrolyte by laser cladding. The effects of the composition of CaO-Al2O3 and the laser cladding process on the structure of auxiliary electrode, the bonding strength with solid electrolyte substrate and the reaction performance with [S] component in molten metal will be studied. The microscopic model for oxygen and sulfur diffusion and the theoretical equation of sulfur sensor will be established, the preparation process of CaO-Al2O3 and laser cladding of auxiliary electrode will be optimized. The formation mechanism and structural model of auxiliary electrode, the bonding mechanism and thermal shock resistance mechanism between solid electrolyte substrate and auxiliary electrode will be illustrated. The kinetic equation of electrode reaction will be established, and the in-situ reaction and interface diffusion of sulfur components will be discussed. The effect and mechanism of temperature and element contents on the performance of sulfur sensor will be revealed, which will provide the theoretical foundation for developing high quality sulfur sensor and determining application condition.