| The small amplitude relative motion which occurs between two contact surfaces is called fretting,fretting is widely spreaded on industry such as automotive, machiner y, aerospace, nuclear reactors,which has been the main reason of parts failure.The for eigh attachs great importances on the high temperature fretting damage in the nuclear industry, the research mainly concentrated in the fuel assemblies and the steam gene rator tube, hard coating usually be used for improving the surface corrosion resistanc e, high temperature resistance and wear resistance, TiN+TiCN+TiN coating is a kind o f typical hard coating, it was used as protection measures anting fretting wear hav e been widely used in various industries because of its high temperature corrosion re sistance, both at home and abroad the research about fretting wear properties of hard coating is litter, especially the research of fretting wear properties of TiN+TiCN+TiN coating on high temperature is rare, so it is necessary for studing the fretting wear of T i N+T i CN+T i Ncoatings at high temperature,which can play a very good effect on the fretting wear in nuclear power equipmentIn this paper, The fretting wear behaviors of TiN+TiCN+TiN coatings and 690 alloy were studied experimentally on a high precision hydraulic fretting wear test rig at elevated temperatures, the "ball plane"contact, The worn scars were examined with Optical Microscopy (OM), electron spectroscopy (EDS), scanning electron microscop y (SEM),Laser Confocal Scanning Microscope (LCSM), the fretting wear behaviors o f TiN+TiCN+TiN coatings and 690 alloy were studied at high temperature and room temperature through analyzing friction coefficient, wear volume and wear scar morpho logy, obtained the following conclusions:(1)the displacement amplitude has small effect on friction coefficient of the coating at room temperature; However,the friction coefficient increases with the increase of lo ad, The wear depth and wear volume of TiN+TiCN+TiNcoatings increase with the dis placement amplitude and normal load increased. With the increase of cycle number. Ti N+TiCN+TiN coating is worn out, the ground down the TiN and TiC hard particles lead to abrasive wear, insteading aggravate the wear and tear of the matrix the wear rate increased drastically,characteristics of materials anting fretting wear decreased, th e wear mechanism of TiN+TiCN+TiN. coating is abrasive wear and delamination at ro om temperature.(2)The displacement amplitude has little influence on friction coefficient of TiN+TiC N+TiNcoating at high temperature, increase with the load increased, wear depth and we ar rate increased with the increase of displacement and load, the main wear mechanis m is oxidation wear accompanied by delamination. with the increase of temperature, th e wear scar width and depth,wear rate increased with increase of temperature when T he temperature ranges room temperature to 200℃, when the temperature ranges from 200℃to 300℃, the difference was not significant, it proved TiN+TiCN+TiNcoatings ha vegood heat resistance.(3) The friction coefficient and wear rate of TiN+TiCN+TiN coating are obviously 1 ess than 690 alloy substrate, which indicates that TiN+TiCN+TiN coating can effective ly improve the anti fretting properties of 690 alloy material,it played a very good prot ective effect, greatly improving the safety and life of 690 alloy tube. |
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