燃气轮机压气机叶片涂层的高温适应性研究

Research of High-temperature Adaptability on Compressor Blade Coatings of Gas Turbines

为探究压气机叶片涂层在更多级叶片上的应用情况,研究了富铝无机盐涂层和铝基硬质涂层的高温适应性,利用光学显微镜、粗糙度测试仪、扫描电子显微镜、能谱仪和拉伸试验机分别测试了涂层厚度、表面粗糙度、微观组织、元素分布和拉伸结合强度。结果表明:富铝无机盐涂层的厚度为40~60μm,喷涂态和热处理后涂层的表面粗糙度分别为0.570~0.685μm和0.734~0.842μm,微观组织在460℃、2000 h内保持稳定,热失效过程涂层中的铝元素向基体快速扩散,金属基体氧化,拉伸结合强度降低;铝基硬质涂层厚度为8~12μm,喷涂态和热处理后涂层的表面粗糙度分别为0.324~0.486μm和1.054~1.275μm,微观组织在460℃、1001 h内保持稳定,热失效过程观察到(Fe,Cr)Al金属间化合物生成,拉伸结合强度约为40 MPa;热处理温度越高、时间越长,铝基涂层越不稳定,当温度不高于460℃时才可满足服役要求。

In order to apply coatings to more grade blades in the compressor,the high-temperature adaptability of inorganic salt aluminum coating and aluminum-based hard coating was studied.The thickness,surface roughness,microstructure,element distribution and tensile bonding strength of coatings were tested by optical microscope,roughness meter,scanning electron microscope,energy dispersive spectroscopy and tensile testing machine.Results show that for the inorganic salt aluminum coating,the thickness is 40~60μm,and the surface roughness of the sprayed coating and the heated coating is 0.570~0.685μm and 0.734~0.842μm,respectively;the microstructure remains stable within 460℃and 2000 h;during the thermal failure process,the aluminum in the coating diffuses rapidly to the substrate,the metal substrate oxidizes and the tensile bonding strength decreases.For the aluminum-based hard coating,the thickness is 8~12μm,and the surface roughness of the sprayed coating and the heated coating is 0.324~0.486μm and 1.054~1.275μm,respectively;the microstructure remains stable within 460℃and 1001 h;(Fe,Cr)Al intermetallic compound occurs during the thermal failure process,and the tensile bonding strength maintains at 40 MPa.Aluminum-based coatings are more unstable with the higher heat treatment temperature and the longer time.When the temperature is not higher than 460℃,the service requirements may be met.