单晶高温合金铂改性铝化物涂层的高温氧化行为  

High Temperature Oxidation Behavior of Pt Modified Aluminide Coating on Single Crystal Superalloy

作　　者：戴建伟[1] 易军 王占考 王凯[1] 许振华[1] 何利民[1] 

机构地区：[1]北京航空材料研究院,北京100095 [2]总参陆航部装备发展办公室,北京100083

出　　处：《航空材料学报》2015年第5期32-38,共7页Journal of Aeronautical Materials

摘　　要：采用化学气相沉积(CVD)方法在单晶高温合金基体上分别制备了单一铝化物和铂改性铝化物涂层,研究了1050℃下两种涂层在空气中的高温氧化行为。采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)等方法分析了铝化物涂层在氧化过程中相成分和显微组织的演变规律,结果表明:经1050℃氧化250h后,两种涂层的氧化动力学曲线均符合抛物线演变规律,Pt-Al涂层的抗氧化性能相对于单一Al涂层提高了2倍以上;涂层主要由β、γ'和α-Al2O3三种物相组成;随着氧化时间的延长,两种涂层表面均出现了氧化膜的脱落现象,但Pt-Al涂层表面氧化膜的脱落面积较小;涂层中相变过程的产生、γ'相贯穿整个涂层和混合氧化物层过早形成是导致铝化物涂层氧化剥落失效的主要原因。Pt元素的加入既可减缓β→γ'的相变速率,又可有效阻挡基体中难熔金属元素的外扩散行为,保证了高质量α-Al2O3保护膜的生成。Single aluminide and Pt modified aluminide coatings were fabricated by chemical vapor deposition（ CVD） on the single crystal superalloy substrates and their high-temperature oxidation behaviors at 1050℃ were investigated. The phase composition and microstructure of the two aluminide coatings were analyzed by XRD,SEM and EDS. The results indicat that both of the oxidation kinetics curves of the two aluminide coatings are in accord with parabolic rule after oxidation at 1050℃ for 250 h. The performance of oxidation resistance of Pt-Al coating has been improved more than two folds as compared with single Al coating. The two aluminide coatings are mainly composed of three phases of β,γ＇ and α-Al2O3. The spallation of oxide scale is gradually observed on both of the two coatings＇ surface with the increment of oxidation time. However the spallation area of Pt-Al coating is relatively smaller than that of Al coating.The phase transition,the penetration of γ＇ phase and the early formation of mixed oxides are probably the primary reasons responsible for the degradation of the coatings. The addition of Pt element can reduce the velocity of β→γ＇ phase transition,inhibiting the outward diffusion of refractory metal elements from substrate to coating and further ensuring the formation of high quality α-Al2O3 scale.

关 键 词：铂改性铝化物涂层 化学气相沉积 氧化 相变 氧化膜 

分 类 号：TG174.4[金属学及工艺—金属表面处理]