Tribological behavior of virgin and aged polymeric pipes under dry sliding conditions against steel

Abstract

The aim of this work is to establish a better understanding regarding the tribological behavior of industrial composite pipes based on polyvinyl chloride (PVC) reinforced with calcium carbonate (CaCO3). The tribological behavior of the composite samples was studied using pin-on-disc tribometer. Furthermore, effects of hygrothermal ageing on friction and wear of composite pipes were studied. The friction coefficient and wear properties were investigated for both virgin and aged composite samples. The wear performance of different samples was evaluated based on specific wear rate measurements. Optical micrographs of the worn composite samples and the steel pins were considered to understand wear damage mechanisms. From the main obtained results, it was shown that the accelerated hygrothermal ageing has a negative effect on the tribological properties of PVC/CaCO3 composites when the absorbed water does not play the role of a cooling fluid to dissipate the frictional heat (COF values). But, it has a positive effect when the absorbed water acts as a good lubricant for the studied materials to reduce the friction forces between the sliding counterparts. At 90 °C during 90 days, the wear damage mechanisms between rubbing pair are combining abrasive wear by the formation of scratches and adhesive wear. Optical micrographs of the steel ball have shown that there are some materials transfer from the body to the counterbody: wear debris detached from the polymeric material and then adhered on the steel ball indicating formation of transfer film. Finally, some insights into the relationship between the hygrothermal ageing mechanisms, wear process and wear damage mechanisms were provided.