Hits:

Indexed by:期刊论文

Date of Publication:2012-06-01

Journal:MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

Included Journals:SCIE、EI

Volume:546

Page Number:162-168

ISSN No.:0921-5093

Key Words:Surfaces; Strength; Borides

Abstract:The isothermal oxidation of the ZrB2-SiC-ZrC ceramic was carried out at a constant temperature of 1000 +/- 2 degrees C, 1200 +/- 5 degrees C and 1400 +/- 5 degrees C, respectively, for different times in static air. The surface oxidation was favorable to increase the flexural strength of the ZrB2-SiC-ZrC ceramic because the flaws on the surface of the specimen were healed by the glass layer. The distribution of strength significantly decreased as the oxidation time increased in spite of the oxidation temperature. The analysis on the mechanism of the strength increase indicated that the strength increased as the reaction rate increased, and the increase in strength was related to change rate in volume induced by reaction, the initial crack geometry, elastic modulus and the surface free energy and so on. (C) 2012 Elsevier B.V. All rights reserved.