Improving the High‐Temperature Oxidation Resistance of Nb4AlC3 by Silicon Pack Cementation. Issue 2 (7th December 2013)

• Record Type: Journal Article
• Authors: Zheng, Liya; Wang, Jingyang; Zhou, Yanchun
• Editors: Cinibulk, M.
• Is Part Of: Journal of the American Ceramic Society. Volume 97:Issue 2(2014)
• Page Start: 552
• Page End: 561
• Publication Date: 2013-12-07
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.12667
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract : Niobium aluminum carbide (Nb4 AlC3 ), as a member of the MAX phases, can retain its stiffness and strength up to over 1400°C. However, its applications are limited due to its poor oxidation resistance at high temperatures. In this work, silicon pack cementation has been applied to improve the oxidation resistance of Nb4 AlC3 . After Si pack cementation at 1200°C for 6 h, a dense and uniform silicide coating which was mainly composed of NbSi2 and SiC and well bonded to the matrix was successfully formed on the surface of Nb4 AlC3 . The Si pack cemented Nb4 AlC3 shows excellent oxidation resistance up to 1200°C due to the formation of protective Al2 O3 layer. The oxidation kinetics of the cemented Nb4 AlC3 obey parabolic law all the way to up to 1200°C, and the parabolic rate constants of cemented Nb4 AlC3 are in the same order of magnitude as those of Ti3 AlC2 in the temperature range 1000°C–1200°C. However, the oxidation of the cemented Nb4 AlC3 was accelerated after oxidation at 1300°C for about 15 h due to the formation of NbAlO4 .