Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5438027 | Ceramics International | 2017 | 13 Pages |
Abstract
To investigate the effect of preparation methods on the La-Mo-Si (LMS) coatings, we developed a new LMS coating system using pack cementation (PC) and supersonic atmospheric plasma spraying (SAPS). Microstructure analysis showed that the SAPS-LMS coating possessed a higher porosity than that of the PC-LMS coating. Higher porosity can provide more channels to the oxidative and corrosive gasses to permeate the SAPS-LMS ceramic top-coat. After static oxidation for 150Â h under 1773Â K, the mass loss of SAPS-LMS coating (3.12Â wt%) was much higher than that of the PC-LMS coating (0.05Â wt%), and the parabolic rate constants presented faster oxidation kinetic in SAPS-LMS coating with respect to the PC-LMS coating. These results revealed that the protection effectiveness of SAPS-LMS coating was inferior to PC-LMS coating. Compared with SAPS-LMS coating, microscopic pores and cracks appeared in the PC-LMS coating with a thicker oxide film, which benefits from the formed La-Si-O-Al glass oxide with an excellent ability for crack healing. The reasons for poor antioxidant performance of SAPS-LMS coating are the higher volatility of La-Si-O glass containing Mo5Si3 and a weak interfacial interaction between coatings and substrate.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Changcong Wang, Kezhi Li, Xiaohong Shi, Caixia Huo, Qinchuan He,