Observations of delamination fatigue on pre-cracked ceramic elements in rolling contact

Abstract

Subsurface cracks on delaminated ceramic elements are experimentally investigated after testing in lubricated rolling contact conditions. In the case of hot isostatically pressed silicon nitride in contact with steel, radial and lateral pre-cracks initiate failure and the propagation mode is observed as delamination fatigue. The extent of subsurface crack length, depth and shape is investigated using a dye penetration method and an acoustic microscopy method. The observations of the subsurface crack provides evidence of lubricant driven delamination fatigue failure.