Mechanical characterization of highly porous beta-Si3N4 ceramics fabricated via partial sintering & starch addition
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, vol.33, no.9, pp.1507-1515, 2013 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 33 Issue: 9
- Publication Date: 2013
- Doi Number: 10.1016/j.jeurceramsoc.2012.10.036
- Journal Name: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.1507-1515
- Keywords: Porous beta-Si3N4, 4-Point bending strength, Fracture toughness, Microstructural evolution, SILICON-NITRIDE CERAMICS, PHASE-TRANSFORMATION, FRACTURE-TOUGHNESS, HIGH-STRENGTH, SI3N4, MICROSTRUCTURE, BEHAVIOR, ND, RE
- Anadolu University Affiliated: Yes
Abstract
In this study, porous beta-Si3N4 ceramics containing limited amount of Sm2O3 and CaO as sintering aids were produced by addition of potato starch (10 and 20 vol.%) and partial sintering. Two different Si3N4 powders, alpha- and beta-, were used as starting materials. Scanning electron microscopy investigations revealed that development of elongated beta-Si3N4 grains were much more pronounced when alpha-Si3N4 starting powder was used. Even though porosity values of the compositions prepared by using alpha-Si3N4 (similar to 57.0-58.4%) is significantly higher than the samples produced by beta-Si3N4 (42.6%), no significant change was observed for the bending strength, fracture toughness and Weibull modulus. This indicates that microstructural features have a significant contribution to the mechanical properties of the porous materials in terms of bending strength and fracture toughness. (C) 2012 Elsevier Ltd. All rights reserved.