Journal of Inorganic Materials

• Research Letter • Previous Articles    

Corrosion Behavior of AlNbO4/Mullite Composite as Environmental Barrier Coating in Water Vapor Environment

WU Jiang, LIN Hong, LI Jian-Bao, LI Jun-Feng   

  1. (State Key Lab of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China)

  • Received:2009-10-22 Revised:2009-12-09 Online:2010-04-20 Published:2010-04-27
  • Contact: LIN Hong E-mail:hong-lin@mail.tsinghua.edu.cn

Abstract:

AlNbO4/mullite composite environmental barrier coating (EBC) with 5mol% AlNbO4 content was prepared on Si3N4 substrate by atmospheric plasma spraying (APS). There was evidence that the weight loss rate of Si3N4 substrate coated by AlNbO4/mullite composite was less than that of Si3N4 substrate coated by mullite during the first 50h corrosion test. The improved protective capacity of AlNbO4/mullite composite coating was ascribed to the formation of glassy AlNbO4 top surface. After 100h corrosion test, the AlNbO4/mullite coating was still stable and no further corroded cavities were observed. However, slight delamination of the coating and a faster weight loss rate was observed after long time corrosion due to the coefficient of thermal expansion (CTE) mismatch between AlNbO4/mullite composite and Si3N4 substrate.

Key words: mullite, AlNbO4, environmental barrier coating, water vapor corrosion

CLC Number: 

  • TQ174