Hertzian contact damage in silicon nitride ceramics with different porosity contents

N. Azeggagh, L. Joly-Pottuz, D. Nélias, J. Chevalier, M. Omori, T. Hashida

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

This work investigates the Hertzian contact damage in Si3N4 ceramics with 3 and 18% porosity processed by spark plasma sintering technique. Low densification was achieved by sintering at pressures lower than needed for a full density. The indentation tests were performed using diamond spheres of various sizes to evaluate the Hertzian contact damage at different scales. Surface damage was observed under electron microscopy while subsurface damage was examined using focused ion beam sectioning technique. Different failure modes were noticed, depending on the size of the volume solicited and the porosity content. At small scale, short cracks initiate from the existing pores then coalesce leading to a quasi-plastic failure mode. At larger scale and for high porosity content, surface ring and radial cracks usually observed for dense brittle materials vanish; the damage mode is mostly related to the fragile rupture of bridges between collapsed pores.

Original languageEnglish
Pages (from-to)2269-2276
Number of pages8
JournalJournal of the European Ceramic Society
Volume35
Issue number8
DOIs
Publication statusPublished - 2015 Aug 1

Keywords

  • Contact damage
  • Hertzian contact
  • Porous materials
  • SiN
  • Size effect

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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