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Fretting wear is a surface destruction process, a tight fit in the small displacement amplitude (microns) the vibration almost two contact surfaces can be observed; has become a nuclear power, aviation, railway and other industrial areas of the major causes of component failure a. In nuclear reactors because of the special high-temperature environment, so that the steam generator tubes and the support member in the circulating flow of the cooling water of the high temperature loop serious high temperature fretting damage. One of the hard coat layer having a high hardness, wear resistance, and chemical stability as fretting wear protective measures are widely used in various industries. Fretting wear study hard coating is generally conducted at ambient temperature, and high temperature fretting wear study reported very small. Hard coatings for high temperature fretting wear behavior, slow down the nuclear power equipment and protection is important. In high-precision hydraulic high temperature fretting wear tester, ball / plane contact mode, fretting wear behavior of TiAlN coating and the substrate Ti-Al-Zr high temperature titanium alloy. Analysis of the friction coefficient, wear volume and the wear scar morphology; using a laser scanning confocal microscope (LCSM) measuring the amount of wear, with an optical microscope (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and surface contour The microscopic analysis instrument, such as grinding Ban. System to study the coating and substrate at different displacement amplitude, normal load and temperature wear behavior to explore its high temperature fretting wear mechanism. The main conclusions of the paper are as follows: (1) Law-impact loads on the friction coefficient of the coating and the substrate, and both increase with increasing load; displacement amplitude of the friction coefficient did not change significantly (especially in the stabilization phase). The friction coefficient curve at 400 ℃ volatile. (2) changes in the normal load and displacement amplitude fretting damage the coating have a greater impact, the wear volume with the normal increase in load or displacement amplitude increases. Room temperature, with the increase of the load, the coating wear scar morphology becomes rough, while at high temperatures, the morphology of the wear scar has become relatively smooth; change in the amplitude of displacement at high temperatures do not significantly impact the morphology of the wear scar . (3) Temperature of fretting wear performance for two behaviors: ① the temperature rise so that the local region of the coating and substrate the prone adhesion and plastic deformation, and the different thermal expansion coefficients of the coating and the substrate; under alternating stress cracks in the area of ??weakness of the interface and the coating, resulting in the fracture of the coating, peeling, increased wear and tear; ② elevated temperatures so that between the surfaces prone to oxidation, when the dense layer in the outermost surface covering of the wear scar, compaction of the oxide layer when self-lubricating and protective effect on the contact surface will reduce wear and tear. Between 25 ° C to 200 ℃, to the behavior of the first master, the friction coefficient and the amount of wear as the temperature rises and increases; second behavior between 200 ° C to 400 ℃ The friction coefficient and the wear amount was decreased as the temperature increased. (4) at room temperature and 200 ° C, TiAlN coating wear mechanism is abrasive wear, oxidation wear and delamination together 400 ℃, the main wear mechanisms of oxidation wear and flaking. Many spalling pits, wear to delamination and abrasive wear of the substrate at room temperature, the central area of ??the wear scar mainly mainly adhesion and flaking; 200 ° C, 400 ℃ delamination wear, oxidation, wear and adhesion the wear based; matrix wear scar profiles show the wear scar area there are three distinct regions: an oxide layer, tribological white layer and the substrate layer. (5) and the substrate, Ti-Al-Zr titanium alloy contrast, the coefficient of friction of the coating in the same conditions at room temperature stability and maximum values ??than those of the base body is small; but when the coefficient of friction of the coating at high temperature is slightly higher than the base body. Without any room temperature or high temperature, the wear volume of the coating is significantly smaller than the base body, the wear scar damage is relatively minor, and exhibit good anti-fretting wear performance, improved wear properties of the surface of the substrate.
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