空心叶片氧化铝基陶瓷型芯高温高压脱芯工艺研究

Leaching-Out Technology of Alumina-Based Ceramic Cores from Hollow Blades Using High Temperature and High Pressure Alkaline Solutions

与燃机叶片用氧化硅基陶瓷型芯相比,氧化铝基陶瓷型芯强度高,耐高温性能好,但脱出性较差,制约氧化铝基型芯广泛使用。采用高温高压KOH水溶液作脱芯液,以某燃机空心叶片试验件为研究对象,通过设计正交试验,研究了温度、压力、浓度对脱芯反应速率的影响规律。基于数据计算、理论分析及试验验证结果,得出温度是影响脱芯速率的主要因素,其次为压力,且随着温度及压力升高,脱芯效率均显著提升。采用优选方案,脱出了空心叶片中的氧化铝基陶瓷型芯。

Compared with silica-based ceramic cores for gas turbine blades, alumina-based ceramic cores are characterized by higher strength and better performance at high temperatures, while their poor leach ability limits the applications of the cores. KOH solutions at high temperatures and high pressures were used as leaching agents to study the leaching-out rates of alumina-based ceramic cores for a certain gas turbine hollow blade. The specially designed orthogonal experiments were carried out to analyze the effects of temperature, pressure and mass concentration of solutions on leaching rate. Based on numerical calculation, theoretical analysis and experimental results, temperature is the main factor affecting the leaching-out rate, followed by pressure, and with the increase of temperature and pressure, the leaching-out rate is significantly improved. The alumina-based ceramic core could be removed from the hollow blade by adopting the optimum scheme.