Articles
  • Effects of pressureless two-step sintering on the densification and properties of tetragonal zirconia

  • H.C. Alexander Cheea, R.S.K. Singha,b and K.Y. Sara Leec,*

  • aFaculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
    bFaculty of Engineering, Universiti Teknologi Brunei, Tungku Highway, Gadong BE1410, Brunei Darussalam
    cTunku Abdul Rahman University College, Faculty of Engineering & Technology, Department of Mechanical Engineering, 53300, Kuala Lumpur, Malaysia

  • This article is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effects of pressureless two-step sintering (TSS) on the densification and mechanical properties of tetragonal zirconia polycrystals were investigated and compared with that obtained by conventional single-step sintering (SSS). The TSS profile involved firing at a high temperature, T1 of 1450 oC followed by cooling to a lower temperature, T2 of 1250 oC and soaking for various holding time ranging from 2 h to 10 h. The results showed that the tetragonal phase stability was not disrupted by TSS. A high relative density, above 96%, was obtained for the TSS samples regardless of holding time when compared to SSS which exhibited about 99% of theoretical density when sintered at 1450 oC. Nonetheless, the beneficial effects of TSS in enhancing the Vickers hardness and fracture toughness of tetragonal zirconia when compared to SSS, without incurring grain growth have been revealed. The single-step sintering yielded large tetragonal grains, about 0.56 µm, if compared TSS which exhibited a refine microstructure having grain sizes ranging from 0.27 µm (for 2 h holding time) to 0.35 µm (for 10 h holding time). This feature of TSS which allows for the inhibition of grain boundary migration and the activation of grain boundary diffusion at lower dwelling temperature during sintering were responsible for the enhancement of the mechanical properties of tetragonal zirconia


Keywords: two-step sintering (TSS), single-step sintering (SSS), mechanical properties, zirconia, Y-TZP

This Article

  • 2021; 22(3): 289-295

    Published on Jun 30, 2021

  • 10.36410/jcpr.2021.22.3.289
  • Received on May 18, 2020
  • Revised on Jul 2, 2020
  • Accepted on Jul 16, 2020

Correspondence to

  • K.Y. Sara Lee

  • Tunku Abdul Rahman University College, Faculty of Engineering & Technology, Department of Mechanical Engineering, 53300, Kuala Lumpur, Malaysia
    Tel : +(6)03-41450123 Fax: +(6)03-41423166

  • E-mail: leeky@tarc.edu.my