WC-Co Based Coatings On 300M Steel Surface Sprayed By HVOF And Their Tribological Properties

In this paper,the tribological properties,micro hardness,bonding strength,fracture toughness and neutral salt spray corrosion resistance of WC-Co based coating on the surface of 300 M steel by High Velocity Oxygen Fuel were studied.The base material is used for high strength steel 300 M steel which is commonly used in aviation,WC-Co based powder particles with different compositions and different characteristics are selected,and the method of supersonic flame spraying is adopted,Select different ingredients,different characteristics of spray particles in the corresponding spraying process parameters under of WC-Co based coating preparation and through on coating performance test study on WC-Co based coating microstructure structure and mechanical properties,especially the tribological properties have an important impact factors.And the possibility of using the WC-Co based coating instead of hard chromium coating to protect the3000 M steel parts is explored.Through the XRD components on the coating of WC-10Co4 Cr and WC-12 Co two kinds of coating materials and the formation of the analysis shows that the Cr element for inhibition of WC-Co based coating in carbon removal phase production of W2 C was higher than Co elements;respectively through different speeds(200rad/min,400rad/min)loaded with(50N,100 N,150N,200N),test the tribological properties of 40 min wear conditions,comparative analysis of two kinds of coating wear morphology and wear debris morphology,wear loss,friction coefficient and wear mechanism,compared with WC-12 Co coating,WC-10Co4 Cr coating due to the presence of a Cr element,because of its low coefficient of friction,and the wear scar does not appear obvious furrow,show tolerance the friction and wear performance;also found in the detection of microhardness and corrosion resistance,porosity,The effect of Cr element on the comprehensive properties of WC-Co based coatings is very obvious.Through the spray coating on WC-Co substrate microstructure,porosity,microhardness,and between the matrix and the bonding strength and resistance to salt fog corrosion etc.the detection performance analysis,it is found that the characteristics of spraying materials,spraying process parameters and coating processing and other factors on the comprehensive performance of coating also has certain effect: The particles inside the spraying material are more loose and the fluidity is better,which is beneficial to improve the comprehensive performance ofthe coating;Combustion chamber pressure,flame flow temperature,particle spraying velocity and other parameters are higher,the comprehensive performance of the coating is also more excellent;After sealing the hole,the corrosion resistance of the coating can be improved remarkably.By and hard chromium plating layer performance comparison test shows that,spray coating on WC-Co substrate microhardness,fracture toughness,resistance to neutral salt spray corrosion resistance,friction and wear ability etc.the comprehensive performance is significantly stronger in hard chromium plating layer.Supersonic flame spraying process due to contact with acid and alkali corrosive medium,not as plating that of high strength steel parts exist the risk of hydrogen embrittlement.Due to the spray coating on WC-Co substrate and hard chromium plating layer compared to the properties have a unmatched comprehensive advantages,so base sprayed WC-Co coatings can replace of hard chromium electroplating layer for 300 M steel parts surface,to improve the hardness of the matrix surface and the ability of anti friction loss and prolong the service life of the parts.