Transmission Electron Microscopy Study of a 3Y‐TZP Worn under Dry and Water‐Lubricated Sliding Conditions

Abstract

A fine‐grained 3‐mol%‐Y 2 O 3 ‐stabilized t ‐ZrO 2 (3Y‐TZP) was worn under dry and water‐lubricated sliding conditions against a magnesia‐partially‐stabilized zirconia (Mg‐PSZ) counterface. Detailed transmission electron microscopy of cross sections of the worn surface indicated dramatic microstructural changes. The outer region of both test specimens consisted of randomly oriented, fine (6‐8 nm) tetragonal zirconia crystals. Below this, the tetragonal grains had become elongated, corresponding to a 95% reduction in thickness from the starting material for the dry test. Transformation of tetragonal to monoclinic zirconia was first found at a depth of 1.0‐2.2 µm (water‐lubricated) and 2.2‐3.5 µm (dry) and extended up to a maximum depth of ∼6 µm. Evidence of dislocation flow was found in all phases. The mechanisms of the microstructural change are discussed.