Nb-Hf合金表面Si-Ti-Cr硅化物涂层在大气和真空中的高温热震性能

High-Temperature Thermal Shock Performance of Si-Ti-Cr Silicide Coating on Nb-Hf Alloy Surface in Atmosphere and Vacuum

摘要:

为了提高Nb-Hf合金的高温热震性能，采用浆料烧结和高温渗透法制备了Si-Ti-Cr硅化物涂层，对比分析了Si-Ti-Cr硅化物包覆的Nb-Hf合金样品在大气和真空条件下的高温热震性能。通过模拟在热冲击过程中涂层的温度场和热应力场分布，揭示了Si-Ti-Cr涂层在大气和真空条件下的热冲击失效机理。结果表明，在1300 ℃热震循环100次条件下，涂层的真空失重小于0.8 mg/cm²；在1600 ℃热震循环200次条件下，涂层的空气增重小于3 mg/cm²。硅化物涂层在1300 ℃真空环境下和1600 ℃空气环境下具有优异的抗热震性能。

Abstract:

To improve the high-temperature thermal shock performance, the Si-Ti-Cr silicide coatings were prepared on Nb-Hf alloy by slurry sintering and high-temperature permeation methods. The high-temperature thermal shock performance of Si-Ti-Cr silicide-coated Nb-Hf alloys in atmosphere and vacuum was comparatively analyzed. The failure mechanism of Si-Ti-Cr coating in atmosphere and vacuum after thermal shock tests was determined by simulating the temperature and thermal stress distributions of the coating during thermal shock. Results show that the mass loss of the coating in vacuum is less than 0.8 mg/cm² after 100 thermal shock cycles at 1300 °C. The mass gain of the coating in atmosphere is less than 3 mg/cm² after 200 thermal shock cycles at 1600 °C. Therefore, the silicide coating exhibits excellent thermal shock resistance at 1300 °C in vacuum and at 1600 °C in atmosphere.