Polymer derived oxidation barrier coatings for Mo-Si-B alloys. Issue 15 (December 2017)

• Record Type: Journal Article
• Authors: Smokovych, Iryna; Hasemann, Georg; Krüger, Manja; Scheffler, Michael
• Is Part Of: Journal of the European Ceramic Society. Volume 37:Issue 15(2017)
• Page Start: 4559
• Page End: 4565
• Publication Date: 2017-12
• Subjects: Polymer derived ceramics -- Preceramic polymers -- Perhydridopolysilazane -- Mo-Si-B based alloys -- Oxidation barrier coatings; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2017.06.048
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Thermodynamic analysis was carried out to predict the phase composition of a perhydridopolysilazane-type polymer derived ceramic coating on Mo5 SiB2 matrix particles after heat treatment. The most probable chemical reactions between these constituents and resulting phases were calculated. The feasibility of PHPS/Mo5 SiB2 chemical reactions was proved experimentally. An amorphous SiOx Ny phase and free Si were found by X-ray diffraction analysis and Raman spectroscopy. The presence of these two phases explain the improvement in oxidation resistance of the Mo5 SiB2 particles, which was found to be as twice as high at 800 °C and 1100 °C in air, compared to the unprotected plain Mo5 SiB2 phase. The oxidation of the free silicon provided by the PHPS conversion was addressed as an oxygen trap.