NiCoCrAlYSiB+AlSiY梯度涂层恒温氧化行为

来源期刊：金属学报2011年第5期

论文作者：王维新 姜肃猛 卫广智 马军 宫骏 孙超

文章页码：578 - 586

关键词：梯度涂层； 电弧离子镀； 恒温氧化； 互扩散

Key words：gradient coating； arc ion plating； isothermal oxidation； interdiffusion

摘    要：采用电弧离子镀技术在镍基单晶高温合金基体上制备了NiCoCrAlYSiB涂层和(NiCoCrAlYSiB+AlSiY)梯度涂层,对比研究了2种涂层退火态的组织结构和在1000,1100和1150℃下的恒温氧化行为.结果表明:退火处理后,NiCoCrAlYSiB涂层是由γ/γ相和弥散其中的点状β-NiAl相构成;(NiCoCrAlYSiB+AlSiY)梯度涂层分为两层,外层以β-NiAl相为主,含有少量的Cr3Si相、内层和NiCoCrAlYSiB涂层的结构相似.NiCoCrAlYSiB涂层在1000℃下有良好的抗氧化性能,在1100和1150℃下因表面生成保护性较差的尖晶石相而快速退化;(NiCoCrAlYSiB+AlSiY)梯度涂层在1000-1150℃下均表现出良好的抗高温氧化性能,1100℃度下氧化300 h后仍有大量的β-NiAl相存在,1150℃下氧化300 h后涂层中Al含量仍在8%(质量分数)以上,少量的β-NiAl相和过饱和的γ/γ相可维持表面Al₂O₃膜的形成和修复.

Abstract: Conventional NiCoCrAlYSiB coating and (NiCoCrAlYSiB+AlSiY) gradient coating were prepared by using arc ion plating (AIP)on the Ni base single crystal superalloy substrate. Comparative studies of the morphology and microstructure together with high temperature oxidation behaviors at 1000,1100 and 1150℃ for the two different coatings were investigated.The results show that after vacuum annealing,the conventional coating is mainly composed of general γ′/γ and a small quantity of β-NiAl dispersed in γ′/γ while the outer layer of the gradient coating consists of β-NiAl and dispersed α-Cr and Cr₃Si inβ-NiAl and the inner layer consists of Cr-rich phases plus minor β-NiAl.The conventional coating has excellent oxidation resistance only at 1000℃.while it degraded rapidly at 1100℃ and 1150℃,on which surface spinel formation was observed;however, the gradient coating has more excellent oxidation resistance than the conventional one at all the three temperatures.After oxidation for 300 h at 1100℃,there still exists a great amount of β-NiAl,and even after oxidation for 300 h at 1150℃,Al content is higher than 8% (mass fraction),in which a small amount of β-NiAl and supersaturated γ′/γ insure the formation and self repair of alumina.