Effect of AlF3, CaF2 and MgF2 on hot-pressed hydroxyapatite-nanophase alpha-alumina composites

EVİS Z., Doremus R. H.

MATERIALS RESEARCH BULLETIN, vol.43, no.10, pp.2643-2651, 2008 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 43 Issue: 10
  • Publication Date: 2008
  • Doi Number: 10.1016/j.materresbull.2007.10.032
  • Journal Name: MATERIALS RESEARCH BULLETIN
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2643-2651
  • Keywords: ceramics, chemical synthesis, X-ray diffraction, mechanical properties, MECHANICAL-PROPERTIES, ZIRCONIA COMPOSITES, REINFORCED HYDROXYAPATITE, AL2O3, POWDER, HYDROXYLAPATITE, TOUGHNESS
  • Middle East Technical University Affiliated: Yes

Abstract

Nanophase alpha-alumina and hydroxyapatite composites (with and without 5 wt% AlF3, CaF2 or MgF2 added separately) were hot pressed at 1100 degrees C and 1200 degrees C to investigate their mechanical properties and phase stability. Hydroxyapatite slightly decomposed to tri-calciurn-phosphate when there was no F- present. With the addition of AlF3, CaF2 or MgF2 into the composite, it improved its thermal stability and mechanical properties. Substitution of OH- by F- ions in hydroxyapatite was verified by the change in hydroxyapatite's hexagonal lattice parameters and unit cell volume. A fracture toughness of 2.8 MPa root m and mu-hardness of 8.25 GPa were calculated for the composite containing CaF2 after the hot pressing at 1200 degrees C. (C) 2007 Elsevier Ltd. All rights reserved.