The effect of La2O3 on the microstructure and room temperature mechanical properties of t-ZrO2

Nilufer I. B., GOKCE H., MUHAFFEL F., Öveçoğlu M. L., Çimenoğlu H.

CERAMICS INTERNATIONAL, vol.42, no.8, pp.9443-9447, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 42 Issue: 8
  • Publication Date: 2016
  • Doi Number: 10.1016/j.ceramint.2016.02.180
  • Journal Name: CERAMICS INTERNATIONAL
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.9443-9447
  • Keywords: Hardness, Toughness, Lanthanum oxide, Zirconia, ZIRCONIA, STABILITY
  • Istanbul Technical University Affiliated: Yes

Abstract

Structural and mechanical properties of La2O3 added (up to 5 wt%) t-ZrO2 compacts were examined with the aim of optimizing hardness and fracture toughness for room temperature applications. Structural examinations were performed using an X-ray diffractometer and a scanning electron microscope. Mechanical properties of the compacts were determined as modulus of elasticity, hardness and fracture toughness by conducting Vickers indentation tests under test loads of 0.5, 1 and 10 kg. Addition of 0.5 wt% La2O3 deteriorated the room temperature stability of t-ZrO2 by forming m-ZrO2 and coarse polygonal grains in the matrix. Higher concentrations (2 and 5 wt% La2O3) caused precipitation of La2Zr2O2 at the grain boundaries, which also accompanied by a reduction in hardness. Fracture toughness increased with increasing La2O3 content of the compact. Finally, an optimum combination between hardness and fracture toughness was obtained for the 0.5 wt% La2O3 containing compact. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.