The role of porosity in the phase composition evolution and texture formation at the friction surface of partially stabilized tetragonal zirconia ceramics

Abstract

The influence of porosity on the phase composition evolution and texture formation at the friction surface of yttria-partially-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics (ZrO2 + 3 mol % Y2O3) in contact with steel was studied. The Y-TZP ceramic samples with a porosity of P = 0.33 and 3.3% were tested in a rod-on-disk configuration. The sample of higher porosity exhibited a much lower degree of wear. The friction wear was accompanied by irreversible phase transformations from the cubic to tetragonal and from the tetragonal to monoclinic structure. It is suggested that such irreversible phase transformations in porous ceramics favor the development of compressive stresses at the friction surface, which account for the observed behavior.