包埋法制备NiAl涂层NiCrW基高温合金的抗氧化性能  

Oxidation Resistance Behavior of NiAl Coating on NiCrWbased Superalloy by Pack Cementation

作　　者：高杉 邹俭鹏[1,2] Gao Shan;Zou Jianpeng(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;State Key Laboratory for System Integration of High Power AC Drive Electric Locomotive,Zhuzhou 412001,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083 [2]大功率交流传动电力机车系统集成国家重点实验室,湖南株洲412001

出　　处：《稀有金属材料与工程》2022年第3期814-820,共7页Rare Metal Materials and Engineering

基　　金：Natural Science Foundation of Hunan Province(2018JJ2524)。

摘　　要：以CaCl_(2)为活化剂,采用包埋法在NiCrW基高温合金表面制备了NiAl涂层。采用X射线衍射、扫描电子显微镜和能谱仪对涂层表面和横截面进行了分析。结果表明,CaCl_(2)可以替代NH_(4)Cl,是一种有效的活化剂。在950℃下,通过4 h的包埋渗铝,制备出几乎为单相、厚度为30μm的NiAl涂层,涂层与基体之间为富铬中间层。当包埋渗剂填充率小于100%时,NiAl层表面生成针状θ-Al_(2)O_(3)。在1000℃恒温空气氧化试验中,NiAl涂层开始时被高速氧化,然后逐渐变为缓慢氧化,完成了亚稳态针状θ-Al_(2)O_(3)向稳态不规则颗粒状αAl_(2)O_(3)的转变,最终稳定的α-Al_(2)O_(3)为基体提供了良好的抗氧化保护。The NiAl coating was prepared on the surface of NiCrW-based superalloy by pack cementation method with CaCl_(2) as an activator.The surface and cross-section of the coated specimens were analyzed via X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy.Results show that CaCl_(2) can replace NH_(4)Cl as an effective activator.The NiAl coating with an almost single phase structure and a thickness of 30μm can be obtained after pack cementation at 950℃ for 4 h.A chromium-rich interlayer can be observed between the NiAl coating and the substrate.When the filling ratio of the pack powder is less than 100%,the needle-likeθ-Al_(2)O_(3) phase is formed on the NiAl layer surface.During the constant temperature air oxidation test at 1000℃,the NiAl coating suffers from high speed oxidation to slow speed oxidation,which is in agreement with the phase transformation from needle-like metastableθ-Al_(2)O_(3) to irregular granular stableα-Al_(2)O_(3).The final stableα-Al_(2)O_(3) provides a good oxidation resistance for the substrate.

关 键 词：NiCrW基高温合金 NIAL涂层 包埋法 抗氧化 

分 类 号：TG132.3[一般工业技术—材料科学与工程]