ROLE OF Y DURING HIGH-TEMPERATURE OXIDATION OF AN M-CR-AL-Y COATING ON AN NI-BASE SUPERALLOY

被引：55

作者：

TAWANCY, HM ^{[1
]}

ABBAS, NM ^{[1
]}

BENNETT, A ^{[1
]}

机构：

[1] ROLLS ROYCE PLC,DERBY DE24 8BJ,ENGLAND

来源：

SURFACE & COATINGS TECHNOLOGY | 1994年 / 68卷

关键词：

D O I：

10.1016/0257-8972(94)90130-9

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

A study was carried out to determine the role of Y during high temperature oxidation or an M-Cr-Al-Y-type coating on an Ni-base superalloy using various techniques of electron microscopy. Prior to oxidation exposures, Y was found to segregate within an external surface layer of the coating about 5 Irm in thickness as well as within the interdiffusion zone. After exposure at 1000 or 1100 degrees C in still air, Y exhibited a preferential tendency for segregation at grain boundaries of alpha-Al2O3 scale developed by the coating, however, a finite concentration of Y was also present in solid solution. In addition, some of the Y was found to oxidize into a Y-rich oxide ''pegs'' within the alpha-Al2O3 scale and extending into the coating. Experimental results showed that segregation of Y to grain boundaries could maintain a fine-grained scale after exposure for up to 1000 h at 1000 or 1100 degrees C. It was concluded that, for the coating-substrate system studied, Y could improve the protective nature of alpha-Al2O3 scale by various mechanisms operating simultaneously.

引用

页码：10 / 16

页数：7

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