Wear in Ceramic/Ceramic and Ceramic/Metal Reciprocating Sliding Contact. Part 1

This paper is the first of a series of two devoted to an investigation of wear mechanisms in ceramic/ceramic and ceramic/metal sliding contact tribological systems at high temperatures and exhaust gas environment. The first part presents results of the experiments carried out at room temperature and air environment. Scanning electron microscope, optical microscope and X-ray dispersion analysis were used for an identification of wear mechanisms. Surface geometry and morphology, friction coefficients and wear were determined as functions of sliding distance, nominal contact pressure, sliding velocity and mechanical properties of specimens (hardness and fracture toughness). The wear mechanism of ceramics rubbed against ceramics may be attributed to intensive plastic deformation of surfaces resulting in low cycle fatigue. The wear mechanism of ceramics rubbed against metals was polishing and surface fracture, while that of metals was adhesive transfer of material on to ceramic surfaces. Wear rates and friction coefficients were independent of mechanical properties of metallic samples.