Zr[B.sub.2] particles reinforced glass coating for oxidation protection of carbon/carbon composites

• Published in: Journal of advanced ceramics 2019-03, Vol.8 (1), p.102
• Main Authors: Li, Cuiyan, Li, Guibiao, Ouyang, Haibo, Lu, Jing
• Format: Article
• Language: English
• Subjects: Coatings; Oxidation-reduction reactions; Silicon carbides; Silicon compounds; Silicon dioxide
• ISSN: 2226-4108
• DOI: 10.1007/s40145-018-0298-9

A dense Zr[B.sub.2] particles reinforced glass (Zr[B.sub.2]/Si[O.sub.2]) coating was prepared on the SiC coated carbon/carbon composites by a facile sol-dipping approach. The prepared Zr[B.sub.2]/Si[O.sub.2] coating could protect the composites from being oxidized for 160 h at 1773 K with a weight loss of 6.9 mg/[cm.sup.2]. The flexural strength retention ratio of the Zr[B.sub.2]/Si[O.sub.2] coated composites is 87% after oxidation for 160 h at 1773 K. The continuous Si[O.sub.2] glass layer embedded with the submicron ZrSi[O.sub.4] particles was formed during oxidation. This was helpful to lower the diffusion rate of oxygen and improve the stability of Si[O.sub.2] glass film, thus improving the oxidation resistance of the coated samples. After thermal cycles between 1773 K and room temperature for 15 times, penetrated cracks formed in the coating. The weight loss of the Zr[B.sub.2]/Si[O.sub.2] coated sample presented linear relationship, and the final weight loss per unit area was 6.35 mg/[cm.sup.2]. The generation of the penetrative cracks and the debonded coating interface resulted in the failure of the Zr[B.sub.2]/Si[O.sub.2] coating. Keywords: Zr[B.sub.2]/Si[O.sub.2] coating; silica sol; dipping; oxidation resistance