Tribological Experiment Study Of Textured Hard Coating

The laser surface texture has the function of absorbing abrasive debris and storing lubricating oil.The DLC coating has a low friction coefficient due to its self-lubricating property.Both of them are widely studied in the field of tribology;the problem of environmental pollution and waste of resources is becoming more and more severe.Higher requirements are placed on the tribological properties of materials in non-lubricating and less lubricated environments.In this paper,the research object is the textured DLC coating-steel ball friction pair,which combines the effect of surface texture with the self-lubricating properties of the DLC coating.It is used to investigate the tribological properties of textured DLC coatings at low-frequency heavy-load（10N-3Hz）and high-frequency light-load（2N-6Hz）in a non-lubricating medium environment and a less-lubricating medium environment.According to the tribological test,in the dry friction condition,the friction coefficients of the untextured DLC coating in low-frequency heavy-load condition and high-frequency light-load condition are respectively 0.082 and 0.068,and the volume wear rates are respectively 5.752×10^-7mm³·（N·m）^-1 and 1.524×10^-7mm³·（N·m）^-1,And the coating has different degrees of graphitization transformation.For textured DLC coating,the surface texture can reduce abrasive wear,and its tribological properties are mainly related to the roughness of the friction pair and the graphitization of the coating.The friction coefficient and volume wear rate of textured DLC coating at both conditions basically follow the law of increasing as the texture diameter decreases and the texture density increases.In the less-lubricating medium environment,The friction coefficient and volume wear rate of untextured 304 stainless steel under low-frequency heavy-load condition are respectively 0.112 and 60.648×10^-7mm³·（N·m）^-1,respectively,and in high-frequency light load condition are respectively 0.121 and 296.990×10^-7mm³·（N·m）^-1,respectively.The friction coefficient of textured 304 stainless steel is mainly affected by fluid damping and solid shear force,and it’s finally stabilized at 0.11 in two working conditions.In the two working conditions,the wear rate is relatively low when the texture diameter is 50um.However,the wear rate increases with the increasing of density in the low-frequency heavy-load working condition,and decreases with the increase of density in the high-frequency light-load working condition.The friction coefficients of the untextured DLC coating under low-frequency heavy-load condition and high-frequency light-load condition are respectively 0.161 and 0.074.The reason for the low friction coefficient in the latter condition is that unstable lubricating film can be formed between friction pairs and the Graphitization of DLC coating For the textured DLC coating,the high hardness of the coating can maintain the integrity of the texture in the process of friction and wear,and its tribological properties are mainly related to the roughness of the friction pair.