Dry Friction and Wear Characteristics of Impregnated Graphite in a Corrosive Environment

Tribological properties of impregnated graphite are greatly influenced by preparation technology and working conditions and it’s highly susceptible to corrosion environmental impacts,but the experimental research about it are few.In this paper,three kinds of impregnated graphite samples are prepared with different degree of graphitization,the tribological properties of these samples in the dry friction environment and in a corrosive environment are analyzed and contrasted.The tribo-test results show that the friction coefficient of samples is reduced and the amount of wear of samples increase when the graphitization degree of samples increases in dry friction condition.While in a corrosive environment（samples are soaked N2O4）,the friction coefficient and amount of wear are changed little if the graphitization degree of samples are low.If the degree of graphitization increase,the friction coefficient and amount of wear of samples increase too,the amount of wear is 2 to 3 times as the samples tested in the non-corrosive environment under pv value of 30MPa？m/s.The impregnated graphite,which friction coefficient is stable and graphitization degree is in mid level,such#2,is more appropriate to have a work in the corrosion conditions.In this paper,preparation and tribological properties especially in corrosive environment of the impregnated graphite is studied,the research conclusion can provide an experimental and theoretical basis for the selection and process improvement of graphite materials,and also provide some important design parameters for contact seal works in a corrosive environment.

Influence of a carbon-based tribofilm induced by the friction temperature on the tribological properties of impregnated graphite sliding against a cemented carbide

Impregnated graphite has attracted considerable attention and has been widely used as an ideal friction material in many fields.However,the influence of the friction temperature on its tribological properties has not been clearly studied;furthermore,the evolution mechanism of transferred tribofilm is unknown.In this study,the tribological properties of impregnated graphite were investigated at different friction temperatures,and the evolution of the carbon-based tribofilm was also determined.The results revealed that the tribological properties significantly improved with an increase in friction temperature.The friction coefficient and wear depth of impregnated graphite reduced by 68%and 75%,respectively,at a high temperature of 160℃ compared with those of non-impregnated graphite.The significant properties of the impregnated graphite can be attributed to a transferred carbon-based tribofilm with an ordered structure induced by the friction temperature,which uniformly and stably adsorbs on friction interfaces.This study provides an important basis for designing graphite-based friction materials with improved properties suited for industrial applications.