Abstract

t This paper presents the experimental results of wear in rolling hybrid ceramic (Si3N4) bearing material with hydrocarbon HC (R600a, CH (CH3)3, 2-methyl propane/isobutene) refrigerant lubricants. Failure modes and rolling wear performance of these ceramic materials in HC refrigerant environment were analysed. During rolling contact fatigue testing the secondary crack initiation occurs at the maximum tensile region of the contact path. The crack initiation of takes place as the residual stresses are relieved with increase in rolling contact stress cycles. The crack is subsequently propagated in the contact circle. The decrease in residual stress at the contact edges causes a gradual decrease in the maximum tensile stress circle. The original contact circle stress distribution is changed. Gaseous phase of the refrigerant results in severe wear during rolling contact fatigue of hybrid ceramic/steel contact.