Effect of mullite on the microstructure and oxidation behavior of thermal-sprayed MoSi2 coating at 1500 °C. Issue 8 (1st June 2020)

• Record Type: Journal Article
• Authors: Zhang, Guangpeng; Sun, Jia; Fu, Qiangang
• Is Part Of: Ceramics international. Volume 46:Issue 8(2020)Part A
• Page Start: 10058
• Page End: 10066
• Publication Date: 2020-06-01
• Subjects: MoSi2 -- Mullite -- Coating -- Plasma spray -- Oxidation -- Nb alloy; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2019.12.273
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: MoSi2 coatings with different mullite additions (0, 10 wt%, and 30 wt%) were prepared on siliconized Nb alloys and oxidation behaviors of the modified coatings were comparatively investigated at 1500 °C in static air. After oxidation for 140 h, the 10 wt% mullite modified coating presented an outstanding oxidation resistance with a mass loss of 4.06 mg/cm 2 in comparison to the unmodified coating and the 30 wt% modified case. A proper amount of mullite addition in MoSi2 coating can restrain the crystallization of SiO2 during the oxidation process, thus a crack-free oxide scale was obtained so as to prevent the inward diffusion of oxygen. However, excessive addition of mullite (30 wt%) in MoSi2 coating can severely hinder the formation of the crack-free oxide scale due to the volume shrinkage of the amorphous mullite, which accelerated the failure of the protective coatings.