• Home
  • Search Results
  • Microstructure and mechanical properties of MgO-stabilized ZrO₂-Al₂O₃ dental composites.

Microstructure and mechanical properties of MgO-stabilized ZrO₂-Al₂O₃ dental composites.

Journal of the mechanical behavior of biomedical materials (2012-12-25)
C B Abi, O F Emrullahoğlu, G Said
ABSTRACT

The aim of the present study was to investigate the production of tetragonal zirconia (t-ZrO(2)) particles (experimental t-ZrO(2)) from monoclinic zirconia (m-ZrO(2)) and to evaluate the effect of the t-ZrO(2) content on the fracture toughness of alumina-zirconia composites by conducting ASTM E399 standard test. In the laboratory study, t-ZrO(2) powder was produced by heat treating m-ZrO(2) containing 10wt.% MgO. Alumina and alumina-zirconia composite powders containing various types and amounts of m-ZrO(2) and t-ZrO(2) were prepared (0-20 wt.%), shaped by slip casting to achieve a uniform distribution and homogeneous microstructure in accordance with the dimensions of ASTM E399 standards, dried, sintered at three different temperatures: 1400, 1500 and 1600 °C for two hours, and characterized. The results of the XRD analysis showed that t-ZrO(2) was produced at 1400 °C. In t-ZrO(2)-doped alumina composites, t-ZrO(2) partially transformed to m-ZrO(2) after sintering, whereas commercial t-ZrO(2) (Tosoh TZ-3Y) remained intact. SEM studies on samples sintered at 1600 °C revealed that the addition of zirconia inhibited abnormal grain growth of alumina, leading to a homogeneous and equiaxed grain structure, especially at high concentrations of zirconia. ZrO(2)-doping enhanced the fracture toughness of the composites, which increased with an increase in the t-ZrO(2) content. The maximum fracture toughness was 11.5 MPam(1/2) and was observed when the t-ZrO(2) content was equal to 20 wt.%. Alternatively, the maximum fracture toughness for pure alumina was 5.9 MPam(1/2).

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Magnesium oxide, ACS reagent, 97%
Sigma-Aldrich
Magnesium oxide, ≥99.99% trace metals basis
Sigma-Aldrich
Magnesium oxide, ≥99% trace metals basis, -325 mesh
Sigma-Aldrich
Magnesium oxide, nanopowder, ≤50 nm particle size (BET)
Sigma-Aldrich
Magnesium oxide, light, 95%
Sigma-Aldrich
Magnesium oxide, 99.99% trace metals basis
Sigma-Aldrich
Magnesium oxide, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, E 530, light, 98.0-100.5% (calc. for dried substance)
Sigma-Aldrich
Magnesium oxide, tested according to Ph. Eur., heavy
Sigma-Aldrich
Magnesium oxide, (single crystal substrate), ≥99.9% trace metals basis, <100>, L × W × thickness 10 mm × 10 mm × 0.5 mm
Sigma-Aldrich
Magnesium oxide, BioUltra, ≥97.0% (calcined substance, KT)
Sigma-Aldrich
Magnesium oxide, puriss. p.a., ACS reagent, ≥97% (calcined substance, KT)
Sigma-Aldrich
Magnesium oxide, -10-+50 mesh, 98%