HIGH-SPEED SLIDING INDENTATION OF CERAMICS - THERMAL EFFECTS

A diamond indentor is attached to the periphery of an aluminium wheel and slid against ferrite and sapphire surfaces at high speed. A high-frequency response infrared sensor is used to measure the average diamond tip temperature and a piezoelectric dynamometer is used to measure the normal and tangential forces acting on the indentor. The analytical procedure estimates the heat flux at the contact as the product of the shear traction and the tangential velocity. The heat flux is used in conjunction with a Green's function to calculate the interface temperature and the tangential surface stress. The calculated and measured grain tip temperatures are compared and the relative magnitudes of the mechanical and thermal surface stresses are calculated. Finally, the importance of thermal effects on the wear and surface finishing of ceramics is discussed. © 1990 Chapman and Hall Ltd.