热处理对超音速火焰喷涂FeAl-Al涂层组织结构的影响  

Effect of Heat Treatment on the Structure of HVOF-sprayed FeAl-Al Coating

作　　者：向军淮[1] 吴志诚 彭文屹[2] 白凌云[1,2] 刘学璋 XIANG Jun-huai;WU Zhi-cheng;PENG Wen-yi;BAI Ling-yun;LIU Xue-zhang(Jiangxi Key Laboratory of Surface Engineering,Jiangxi Science and Technology Normal University,Nanchang 330013,China;School of Materials Science and Engineering,Nanchang University,Nanchang 330031,China)

机构地区：[1]江西科技师范大学江西省材料表面工程重点实验室,南昌330013 [2]南昌大学材料科学与工程学院,南昌330031

出　　处：《表面技术》2020年第5期98-102,154,共6页Surface Technology

摘　　要：目的通过超音速火焰喷涂(High Velocity Oxygen Fuel,HVOF)的粉末喂料设计,获取结构致密的铁铝金属间化合物涂层,并详细考察热处理对所制备涂层组织结构的影响。方法在铁铝合金粉末喂料中添加质量分数为5%的铝粉,改善喷涂效果,在316L不锈钢表面制备致密的FeAl-Al涂层,并进行真空热处理。采用X射线衍射仪(XRD)、场发射扫描电子显微镜(SEM)、能谱仪(EDS)及维氏显微硬度计,详细分析了涂层在不同热处理温度下的微观组织、成分、结构与显微硬度的变化。结果喷涂态FeAl-Al涂层厚度约为150μm,物相为Fe2Al5,未检测到单质Al。随着热处理温度升高,Fe2Al5相的衍射峰逐渐增强。500℃热处理后,喷涂态涂层中扁平粒子间存在的细微孔隙大量消失,涂层致密性明显提高。但是800℃热处理后,涂层中产生了与界面平行的裂纹。喷涂态FeAl-Al涂层的硬度为465.06HV0.1,500℃热处理2 h后增加至472.06HV0.1,继续提高热处理温度,涂层的显微硬度则明显下降。结论在粉末喂料中引入质量分数为5%的Al粉,可明显改善超音速火焰喷涂效果,获得结构致密、与基体结合牢固的FeAl-Al涂层。合适的热处理能进一步消除喷涂缺陷,使涂层显微硬度增加,微观结构更加致密。The work aims to obtain the FeAl intermetallic coating with dense structure by redesigning feedstock powder of high velocity oxygen fuel(HVOF), and then investigate the effect of heat treatment on the structure of sprayed coating in details. The spraying efficiency was enhanced by adding aluminum powder with mass ratio of 5% into the feedstock powder to prepare the dense FeAl-Al coating on the surface of 316 L stainless steel. After vacuum heat treatment, the variations in microstructure,composition, structure and micro-hardness of the coating at different heat treatment temperature were investigated in details by X-ray diffractometer(XRD), scanning electron microscope(SEM), energy dispersive spectrometer(EDS) and vickers microhardness tester. The thickness of as-sprayed FeAl-Al coating was about 150 μm and the phase was Fe2Al5. No single Al was detected. The diffraction peak of Fe2Al5 strengthened as the heat treatment temperature increased. After heat treatment at 500 ℃, the micro pores between the flat particles in the spray coating disappeared, and the density of the coating increased obviously. However, cracks parallel to the interface were found in the coating after 800 ℃ heat treatment. Micro-hardness of as-sprayed FeAl-Al coating was 465.06 HV0.1, while it increased to 472.06 HV0.1 after heat treatment at 500 ℃ for 2 hours. The micro-hardness of the coating decreased obviously after the heat treatment temperature increased. The introduction of Al powder with a mass of 5% can obviously improve the efficiency of HVOF, and obtain FeAl-Al coating with dense structure and bonded to the substrate tightly. Proper heat treatment can further eliminate the spraying defects, resulting in the increase of the micro-hardness and compacter microstructure.

关 键 词：超音速火焰喷涂 FEAL金属间化合物 FeAl-Al涂层 热处理 组织结构 显微硬度 

分 类 号：TG174.4[金属学及工艺—金属表面处理]