Refractory Diborides of Zirconium and Hafnium

Journal of the American Ceramic SocietyVolume 90, Issue 5 p. 1347-1364 Refractory Diborides of Zirconium and Hafnium William G. Fahrenholtz, Corresponding Author William G. Fahrenholtz Materials Science and Engineering Department, University of Missouri-Rolla, Rolla, Missouri 65409 *Member, American Ceramic Society.†Author to whom correspondence should be addressed. e-mail: [email protected]Search for more papers by this authorGregory E. Hilmas, Gregory E. Hilmas Materials Science and Engineering Department, University of Missouri-Rolla, Rolla, Missouri 65409 *Member, American Ceramic Society.Search for more papers by this authorInna G. Talmy, Inna G. Talmy Naval Surface Warfare Center, Carderock Division, West Bethesda, Maryland 20817 *Member, American Ceramic Society.Search for more papers by this authorJames A. Zaykoski, James A. Zaykoski Naval Surface Warfare Center, Carderock Division, West Bethesda, Maryland 20817 *Member, American Ceramic Society.Search for more papers by this author William G. Fahrenholtz, Corresponding Author William G. Fahrenholtz Materials Science and Engineering Department, University of Missouri-Rolla, Rolla, Missouri 65409 *Member, American Ceramic Society.†Author to whom correspondence should be addressed. e-mail: [email protected]Search for more papers by this authorGregory E. Hilmas, Gregory E. Hilmas Materials Science and Engineering Department, University of Missouri-Rolla, Rolla, Missouri 65409 *Member, American Ceramic Society.Search for more papers by this authorInna G. Talmy, Inna G. Talmy Naval Surface Warfare Center, Carderock Division, West Bethesda, Maryland 20817 *Member, American Ceramic Society.Search for more papers by this authorJames A. Zaykoski, James A. Zaykoski Naval Surface Warfare Center, Carderock Division, West Bethesda, Maryland 20817 *Member, American Ceramic Society.Search for more papers by this author First published: 10 May 2007 https://doi.org/10.1111/j.1551-2916.2007.01583.xCitations: 1,561 D. Green—contributing editor At UMR, portions of this work were funded by the Air Force Office of Scientific Research (F49620-03-1-0072 and FA9550-06-1-0125), the National Science Foundation (DMR-0346800), and the Air Force Research Laboratory (FA8650-04-C-5704). At NSWCCD the work was funded by the Office of Naval Research on several contracts monitored by Dr. Steve Fishman. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Abstract This paper reviews the crystal chemistry, synthesis, densification, microstructure, mechanical properties, and oxidation behavior of zirconium diboride (ZrB2) and hafnium diboride (HfB2) ceramics. The refractory diborides exhibit partial or complete solid solution with other transition metal diborides, which allows compositional tailoring of properties such as thermal expansion coefficient and hardness. Carbothermal reduction is the typical synthesis route, but reactive processes, solution methods, and pre-ceramic polymers can also be used. Typically, diborides are densified by hot pressing, but recently solid state and liquid phase sintering routes have been developed. Fine-grained ZrB2 and HfB2 have strengths of a few hundred MPa, which can increase to over 1 GPa with the addition of SiC. Pure diborides exhibit parabolic oxidation kinetics at temperatures below 1100°C, but B2O3 volatility leads to rapid, linear oxidation kinetics above that temperature. The addition of silica scale formers such as SiC or MoSi2 improves the oxidation behavior above 1100°C. Based on their unique combination of properties, ZrB2 and HfB2 ceramics are candidates for use in the extreme environments associated with hypersonic flight, atmospheric re-entry, and rocket propulsion. Citing Literature Volume90, Issue5May 2007Pages 1347-1364 RelatedInformation