Pt-Al涂层对一种镍基单晶高温合金抗热腐蚀行为的影响  

Influence of Pt-Al Coating on Hot Corrosion Resistance Behaviors of a Ni-Based Single-Crystal Superalloy

作　　者：王迪 王栋[2] 谢光[2] 王莉[2] 董加胜[2] 陈立佳[1] WANG Di;WANG Dong;XIE Guang;WANG Li;DONG Jiasheng;CHEN Lijia(School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China;Shi-Changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110870 [2]中国科学院金属研究所师昌绪先进材料创新中心,沈阳110016

出　　处：《金属学报》2021年第6期780-790,共11页Acta Metallurgica Sinica

基　　金：国家重点研发计划项目No.2016YFB0701403;国家科技重大专项项目Nos.2017-Ⅵ-0019-0091、2017-Ⅵ-0003-0073和2017-Ⅵ-0001-0070;国家自然科学基金项目Nos.51771204、U1732131、51671196、91860201和51631008。

摘　　要：采用电镀Pt和化学气相沉积渗铝法在一种镍基单晶高温合金表面制备Pt-Al涂层,该涂层为单一β-(Ni,Pt)Al相结构。选用涂盐法分别在无涂层和Pt-Al涂层试样表面涂覆Na2SO4盐,并在900℃常压炉中进行热腐蚀实验。通过热腐蚀动力学、热腐蚀产物、热腐蚀宏观表面形貌和微观结构的对比,分析Pt-Al涂层对镍基单晶高温合金热腐蚀行为的影响。采用XRD、SEM、EDS和EPMA等检测方法进行分析。实验结果表明:经900℃热腐蚀后,Pt-Al涂层可以提高基体合金的抗热腐蚀性能,Pt-Al涂层试样的热腐蚀速率小于无涂层试样;β-(Ni,Pt)Al相中的Pt原子能够抑制S原子向β-(Ni,Pt)Al相中扩散,将S原子阻隔在氧化物-金属界面处,从而降低基体合金的热腐蚀速率;Pt原子也能够将大量难熔的Ta原子阻隔在互扩散区内,仅有少量的Ta原子扩散到氧化物中,减少了Ta2O5的形成;此外,Pt-Al涂层能够在一定程度上抑制氧化膜-金属界面处孔洞的形成。Pt-Al coating has been widely used in engine rotor blades because of its ability to improve the oxidation and hot corrosion resistance of Ni-based superalloys. However, the effect exerted by Pt on S and other refractory elements, as well as the rupture mechanisms, is under debate. To investigate the influence of Pt-Al coating on the corrosion resistance of single-crystal superalloy at high temperature, the hot corrosion test utilized Na2 SO4 salt coated on the surface of the Pt-Al coating samples and the uncoated ones were carried out at 900 ℃, respectively. Using several techniques, such as XRD, SEM,EDS, and EPMA, the influence of Pt-Al coating on the hot corrosion behaviors of a Ni-based single-crystal superalloy was analyzed. Moreover, the hot corrosion kinetics, hot corrosion products, and microstructure evolution during the process were analyzed. The results reveal that the hot corrosion resistance of the substrate alloy was enhanced by Pt-Al coating. The hot corrosion rate of the Pt-Al coating sample was lower than that of the uncoated one. Thus, it can be inferred that Pt-Al coating exhibited better hot corrosion resistance. Pt prevented the diffusion of S into the β-(Ni, Pt)Al phase. The S atom was present at the oxide-metal interface, which reduced the hot corrosion rate of the substrate alloy. The presence of Pt in the β-(Ni, Pt)Al obstructed the great mass of Ta in the inter diffusion zone, which led to the diffusion of only a small quantity of Ta atoms into the oxide, and reduced the formation of Ta2O5. Finally, Pt-Al coating was also found to restrain to some extent the void formation at the oxide-metal interface.

关 键 词：Pt-Al涂层 热腐蚀 单晶高温合金 镍基合金 

分 类 号：TG174.31[金属学及工艺—金属表面处理]