The Influence of Silicon Dioxide on the Stability of the Phase Composition and Mechanical Properties of Alumina-Toughened Zirconia-Based Ceramics

Abstract

The influence of SiO2 impurity (with a concentration varying from 0 to 10 mol %) on the stability of tetragonal ZrO2 (t-ZrO2) and on a set of micro- and macromechanical properties of calcia-stabilized (CCaO = 6.5 mol %) alumina-toughened ( $${{C}_{{{\text{A}}{{{\text{l}}}_{2}}{{{\text{O}}}_{3}}}}}$$ = 5.8 mol %) zirconia-based ceramics (ATZ ceramics) has been studied. It has been found that the introduction of SiO2 ( $${{C}_{{{\text{Si}}{{{\text{O}}}_{2}}}}}$$ = 5 mol %) raises fracture toughness Kc by nearly twofold (from 7.05 to 12.43 MPa m1/2), slightly decreases hardness H (from 12.75 to 10.9 GPa), and improves ultimate compression strength σS (from 2.44 to 2.73 GPa) and ductility (compression strain e grows from 5.3 to 7.3%) of ATZ ceramics. It has been shown that the above improvements were achieved by means of a reduction in t-ZrO2 stability.