Fretting Wear Behavior Of Inconel690 Alloy HVOF Sprayed WC-10Co-4Cr Coating At High Temperature

The heat exchanger tube of steam generator is one of the most important components in nuclear power system.The slight vibration between heat exchanger tubes and their supports causes fretting wear.The continuous fretting wear will lead to initiation and propagation of surface cracks in heat exchanger tube,which will produce security risks and endanger the safety of the nuclear power system.Therefore,it is an important task to prevent the damage of the heat exchanger tube of steam generator.Now there is no systematic method to solve the problem of fretting damage of the heat exchanger tube of steam generator,although the researchers have done a lot of research.In this paper,the high temperature fretting wear test of the Incone1690 alloy tube and high velocity oxy-fuel spraying WC-10Co-4Cr coating was investigated by PLINT electro hydraulic servo high temperature fretting tester with the "ten" cross contact mode.The experimental conditions are as follows:the normal load of 100-200 N,the displacement amplitude of 100?200?m,the frequency of 2 Hz,the number of cycles is 30000 times,the temperature is from room temperature to 300?.the wear scar was analyzed by optical microscope(OM)?electron spectroscopy(EDX)?scanning electron microscopy(SEM)?X ray diffraction(XRD)?NanoMap500DLS dual mode profilometer and 3D confocal microscope(OLYMPUS-OLS4100)instruments,explores the behavior of fretting wear and damage mechanism of Incone1690 alloy tube and WC-10Co-4Cr coating,draw the following conclusions:(1)The displacement amplitude has little influence on the friction coefficient of WC-10Co-4Cr coating at room temperature,the friction coefficient of WC-10Co-4Cr coating increases with the increase of normal load under the same displacement amplitude.The fretting wear mechanism of WC-10Co-4Cr coating is mainly characterized by abrasive wear and delamination,and accompanied by slight friction oxidation at room temperature.(2)WC-10Co-4Cr coating of wear volume increases with the increase of displacement amplitude and normal load at high temperature of 200? and 300?.The fretting wear mechanism is mainly characterized by abrasive wear and delamination,but there are signs of oxidative wear at high temperature of 200?.The fretting wear mechanism is mainly characterized by oxidation wear,and accompanied by delamination at high temperature of 300?.(3)WC-10Co-4Cr coating of wear volume is and the two-dimensional contour section area are less from room temperature to high temperature of 200?,which indicates that the HVOF sprayed WC-10Co-4Cr coating can effectively improve Incone1690 alloy substrate of the wear resistance and fretting wear resistance,WC-10Co-4Cr coating is seriously worn at high temperature of 300?.