火焰喷涂NiCrFe-Al-hBN涂层的高温稳定性研究

Research of thermal stability of NiCrFe-Al-hBN abradable seal coating

采用火焰喷涂方法在GH4169合金基体表面制备了NiCrFe-Al-hBN涂层,将NiCrFe-Al-hBN涂层在700℃和815℃进行热处理,分析了涂层的硬度、结合强度和微观形貌变化,并对不同温度热处理后的涂层与高温合金叶片的可磨耗性能进行了评价和分析。研究结果表明:NiCrFe-Al-hBN涂层经700℃高温处理50h、100h和150h后,随着热处理时间的延长,硬度变化不明显,硬度增加1.37%,结合强度与喷涂态相比相当。通过对涂层显微组织分析发现,在该温度热处理后涂层的显微组织未发生明显变化。在700℃,线速度450μm/s,50μm/s进给速度刮擦试验条件下,喷涂态NiCrFe-Al-hBN涂层的IDR值为3.36%,经700℃下处理150h后涂层的IDR值为3.86%,均满足压气机的使用要求,涂层在700℃下热稳定性能优异,可在该温度条件下长时间应用。涂层在815℃热稳定性不理想,随着热处理时间的延长,涂层硬度和结合强度均增加,可磨耗性能明显下降。

NiCrFe-Al-hBN coating was prepared on the GH4169 substrate using flame spraying method.The high-temperature stability of the NiCrFe-Al-hBN coating at 700℃and 815℃was analyzed.The variations of microstructure hardness,bonding strength,and microstructure of the coating with the increasing of temperature were analyzed,and its abradability with the mate of GH4169 alloy blade was also evaluated and researched.The research results indicate that after high temperature treatment at 700℃for 50 h、100 h、and 150 h,the hardness of NiCrFe-Al-hBN coating does not change significantly,with an increase of 1.37%.The bonding strength is comparable to the sprayed state.The microstructure results indicate that there is no significant change with 700℃heat treatment temperature.When the abradability test conditions are:temperature is 700℃,linear speed is 450μm/s,with a feed speed of 50μm/s,the IDR value of NiCrFe-Al-hBN coating is 3.36%,and after treatment at 700℃for 150 hours,the IDR value is 3.86.Both of the above coatings are meet the requirements of compressor.The results indicate that NiCrFe-Al-hBN coating shows excellent thermal stability for long term service at or below 700℃.Thermal stability is unsatisfactory at 815℃,the hardness and bonding strength increased with the extension of heat preservation time,the abradability of the coating degenerates significantly.