Behavior of the Submicron Crystalline Y-TZP–Al2O3 Composite in Dry Friction with Steel

Abstract

The paper discusses the wear resistance, friction coefficient, and structure of worn surfaces of submicron crystalline Y–TZP–Al₂O₃ composite rubbed against a steel disk counterface at a pressure of 5 МPа in a range of sliding speeds from 1 to 20 m/sec. It is shown that, starting at 2 m/sec, the friction surface is subdivided by a crack network into isolated blocks. Local ceramic spalling is developed at the maximum wear rate at a sliding speed of 5 m/sec in these blocks. The intensities of X-ray diffraction peaks of the tetragonal phase are inversed with respect to the initial state; they are characterized by random crystalline grain orientation. The degree of this inversion increases with sliding speed. These results are discussed in terms of effects exerted by the reorientation of martensite-free deformation twins in the tetragonal phase and the formation of a quasi-liquid film on the wear resistance of Y–TZP–Al₂O₃.