Study on Mechanisms of Wear of 45 # Steel by Natural Rubber in Water Medium

The rubber metal tribo couples have been widely used in a number of hydromachines and oil field equipment, in order to prolong the service life of these couples,researchers have paid much attention to improving the wear resistance of the rubber but ignored the wear of metal by rubber. Theoretical and experimental approches to date left a great member of questions unanswered,therefore here described is the initial study on mechanisms of wear of metal by natural rubber in the water medium. The surface profile.elements constitutions and binding energies of metal and rubber surfaces have been analyzed by using scanning electron microscopy(SEM) and X ray photoelectron spectroscopy(XPS).The functional groups of natural rubber surfaces have been analyzed by using fouriey transform infrared spectrometer(FT IR).It has been found that the physical process of wear is mainly microcutting action of the wear debris and the particles of the additive.As for the surfacial chemical effects could be summarized as follows: (1) Mechanical rupture of rubber macromolecular chains; (2) Oxidative degradation of natural rubber surface; (3) The metal polymer compound which remains on the metal surface is produced due to the mechanochemical reaction between metal and rubber; (4) Reaction between carboxylic acid groups and metal; (5) Corrosion of metal induced by the water medium.The process of rubber wearing metal can be divided into two stages: (1) The mechanochemical reaction among metal, rubber and medium forms a layer of chemical reaction film of the metal surface; (2) The chemical reaction film being peeled off by the action of microcutting leads to the wear of metal.It has been concluded that the wear mechanisms of metal by rubber might be mainly attributed to the chemistry mechanics self catalytic destruction mechanism of metal being rubbed by natural rubber.