激光合金化掺杂TiC对等离子喷涂8YSZ热障涂层热腐蚀行为的影响  

Effect of Laser Alloying TiC Doping on the Hot Corrosion Behavior of Plasma Sprayed 8YSZ Thermal Barrier Coatings

作　　者：张盼盼 孙宇海 孙磊[1,2,3] 李波 张群莉 姚建华[1,2,3] ZHANG Panpan;SUN Yuhai;SUN Lei;LI Bo;ZHANG Qunli;YAO Jianhua(School of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310023,China;Institute of Laser Advanced Manufacturing,Zhejiang University of Technology,Hangzhou 310023,China;Collaborative Innovation Center of High-end Laser Manufacturing Equipment,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]浙江工业大学机械工程学院,杭州310023 [2]浙江工业大学激光先进制造研究院,杭州310023 [3]浙江工业大学高端激光制造装备协同创新中心,杭州310023

出　　处：《中国表面工程》2023年第6期126-134,共9页China Surface Engineering

基　　金：国家自然科学基金青年基金(52105311);浙江省“尖兵”“领雁”研发攻关计划(2023C01052,2022C01117);浙江省自然科学基金(LQ21E010002)资助项目。

摘　　要：传统的等离子喷涂热障涂层在高温环境下服役易受熔融腐蚀盐渗透而过早剥落失效,研究激光合金化掺杂自愈合材料TiC对热障涂层热腐蚀行为的影响具有重要意义。采用大气等离子喷涂技术(Atmospheric plasma spray,APS)在Inconel 718镍基高温合金表面制备NiCrAlY粘结层,采用大气等离子喷涂技术在NiCrAlY粘结层上制备8 wt.%氧化钇部分稳定的氧化锆(8 wt.%yttria partially stabilized zirconia,8YSZ)陶瓷层,构建典型双层结构热障涂层体系。采用1 kW光纤耦合激光器将自愈合材料TiC熔于8YSZ热障涂表层,并考察其在900℃下25%NaCl+75%Na_(2)SO_(4)混合熔盐中保温4 h的热腐蚀行为。结果表明,与等离子喷涂涂层相比,激光合金化改性热障涂层表面更加光滑,分布有网状裂纹,且结构致密。等离子喷涂涂层的热腐蚀产物主要是针状颗粒Y_(2)(SO_(4))_(3)和m-ZrO_(2),但仅有较少的热腐蚀盐渗透至激光合金化改性热障涂层内部,其热腐蚀产物为Y_(2)(SO_(4))_(3)和少量的TiO_(2)。激光合金化改性热障涂层的抗热腐蚀性能较等离子喷涂态热障涂层提升55.5%,一方面激光合金化改性层组织致密,可阻止热腐蚀盐渗透至涂层内部,另一方面,激光合金化改性热障涂层表面粗糙度更低,能减少与热腐蚀盐的接触面积。此外,自愈合材料TiC在高温下发生氧化反应引起体积膨胀,实现裂纹的部分自愈合效应,进一步阻止了热腐蚀反应的发生。采用激光表面改性技术将自愈合材料TiC引入热障涂层,激光合金化改性热障涂层不仅具有光滑的表面形貌,还具有致密的微观组织结构;同时自愈合材料TiC在高温环境下的裂纹自愈合效应有助于抑制热腐蚀盐的渗透,最终提高热障涂层的抗热腐蚀性能。Double-layered thermal barrier coatings (TBCs),which are composed of a top ceramic coating and a bonding coating,are widely used in the industry to reduce the surface working temperature of hot components.The primary materials used for the ceramic coating have been 6-8 wt.%Y_2O_(3) partially stabilized ZrO_(2) (6-8YSZ),which has excellent performance of thermal insulation,high temperature resistance,low thermal conductivity,and effective thermal protection effect on metal substrates.However,traditional plasma-sprayed TBCs contain numerous pores and microcracks,and they are susceptible to corrosive salt penetration at high temperatures,leading to premature peeling failure.Doping with self-healing materials and laser post-treatment methods can effectively improve the hot corrosion resistance of TBCs.Therefore,this study aims to examine the effect of laser alloying on the hot corrosion behavior of plasma-sprayed TBCs.First,a NiCrAlY bonding coating is prepared on the surface of an Inconel 718nickel-based superalloy via atmospheric plasma spray (APS) technology.An 8YSZ ceramic coating is then applied on the NiCrAlY bonding coating.Finally,self-healing TiC is melted on the plasma-sprayed 8YSZ coating by using a 1 k W fiber-coupled laser.The hot corrosion behaviors of the plasma-sprayed and laser-alloyed TBCs are investigated by immersion in 25%Na Cl+75%Na_2SO_(4) mixed salt at 900℃ for 4 h.The weight losses of the plasma-sprayed and laser-alloyed TBCs following hot corrosion are examined.The microstructures of the plasma-sprayed and laser-alloyed TBCs before and after hot corrosion are studied using scanning electron microscopy.X-ray diffraction is used to characterize the phase composition of each coating,and energy-dispersive spectroscopy is used to analyze the elemental compositions.A high-precision electronic balance is used to measure the weights of the plasma-sprayed and laser-alloyed TBCs before and after hot corrosion,and the weight loss due to hot corrosion is determined.The results shows that the surface o

关 键 词：等离子喷涂 激光合金化 热障涂层 抗热腐蚀性能 TIC 自愈合 

分 类 号：TG156[金属学及工艺—热处理] TB114[金属学及工艺—金属学]