TiA1合金表面激光重熔纳米陶瓷涂层热腐蚀性能  

Hot Corrosion Behavior of Laser-remelted Nanostructured Ceramic Coatings on TiAl Alloy Surface

作　　者：田宗军[1] 耿亚维[1] 王东生[1,2] 沈理达[1] 刘志东[1] 高雪松[1] 黄因慧[1] 

机构地区：[1]南京航空航天大学机电学院,江苏南京210016 [2]铜陵学院机械工程系,安徽铜陵244000

出　　处：《应用激光》2010年第2期73-77,共5页Applied Laser

基　　金：国家自然科学基金资助项目(项目编号:59975046;50305010);江苏省自然科学基金资助项目(项目编号:BK2004005;BK2009375)

摘　　要：为了进一步提高TiA1金的耐热腐蚀性能,分别采用等离子喷涂和等离子喷涂一激光重熔复合工艺在TiA1合金表面制备了纳米A1_2O_3-13%TiO_2(质量分数)陶瓷涂层,研究了两种涂层在850℃C下 75%Na_2SO_4+25%NaCl(质量分数)熔融盐中的热腐蚀行为,用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对腐蚀后试样的微观组织以及物相进行了分析,并讨论了激光重熔处理对涂层耐热腐蚀性能的影响。结果表明,等离子喷涂陶瓷涂层的腐蚀情况较为严重,经过激光重熔后可以有效提高其耐热腐蚀性能。激光重熔试样具有较高抗热腐蚀性能的原因是:一方面激光重熔消除了喷涂层的层状结构和大部分孔隙,形成了均匀致密的重熔层,减少了热腐蚀过程中的腐蚀扩散通道;另一方面归因于激光重熔使亚稳相γ-A1_2O_3转变为稳定相α-A1_2O_3。In order to improve the hot corrosion resistance of TiAl alloy, the nanostructured Al2O3-13%TiO2 （mass fraction） ceramic coatings were fabricated by the plasma spraying and plasma spraying-laser remelting technology on TiAl alloy surface respectively. The hot corrosion behavior of the coatings in molten 75%Na2SO4＋25%NaCl （mass fraction） at 850℃ was investigated, and the microstructure and phase constitution of the corrode coatings were researched by scanning electron microscopy （SEM） and X-ray diffractometry （XRD） to inquiry the influences of laser remelting on the hot corrosion resistance of the plasma-sprayed ceramic coating. The result shows that the as-sprayed coating exhibited a quite serious corrosion and the laser-remelted coating had better hot corrosion resistance. One of the reasons for the improvement of hot corrosion resistance of remelted coating is the forming of a dense homogeneous remelted layer without voids, cavities and microcracks, which can hinder the diffusion of corrosion medium and protect the interior from corrosion. In addition, the metastable γ-Al2O3 phase in the remelted area transfers into stable α-Al2O3 phase also helps to improve the hot corrosion resistance.

关 键 词：激光重熔 等离子喷涂 A1_2O_3-13%TiO_2纳米陶瓷涂层 热腐蚀 TiA1合金 

分 类 号：TG156.99[金属学及工艺—热处理]