On the lubrication and wear of metal by rubber

Abstract

A puncture test has been used to investigate the lubrication and wear of metal by rubber. Cylindrical metal indentors are used to puncture a rubber surface under controlled conditions. Several mechanisms are investigated which affect both the lubrication and wear of the metal. A self-lubrication effect is reported whereby there is a drop in puncture load over successive punctures, which correlates with a strong increase in the contact angle of water against the metal surface and is associated with a reduction in metal wear rate. It is suggested that this is due to the formation of a rubbery layer on the metal surface. The wear rates of several different metals are studied and at least one metal showed an enhanced wear rate for its hardness, suggesting some mechanism of polymer radical attack. In most cases, however, metal and rubber hardnesses were the dominant factors in determining wear rates.