Research On High Temperature Fretting Wear Of PIII&D TiN/Ti Composite Coatings

The equipments of Nuclear Power are working in the environment of complex, and high temperature is the nuclear electricity equipment working conditions important characteristic. Core hair should pile up middle than the steam generator and the exchanger arousing tiny one of the cause moving the loss wearing away , already becoming the life-span affecting a nuclear power between propping up a component because of the high temperature sum corrodes the coupling effect. High temperature studying as a result tiny the fretting wear mechanism and operating mechanism have important theory significance and actual value.High temperature fretting wear behavior of TiAlZr titanium alloy substrate and its PIII&D TiN/Ti composites coatings had been studied systematically using the high precision fretting wear apparatus. Their structure and element concentration were analyzed by X-ray Diffraction (XRD) and Energy Dispersion Spectrometer (EDS) respectively. The wear loss had been determined by means of laser confocal scanning microscopy (LCSM), Ambios XP-2 steps instrument, and the wear scar were observed by optical microscope (OM) and scanning electron microscope (SEM). The fretting map PIII&D TiN/Ti composites coatings at different temperature had been built up. Furthermore, the effects of displacement, normal load and temperature on fretting wear had been focused on, and the mechanism of high temperature fretting wear were explored. Main conclusions were drawn as follows:1. The application of PIII&D TiN/Ti composites coatings changes the running condition fretting map of TiAlZr titanium alloy substrate;In the partial slip regime, the wear of PIII&D TiN/Ti composites coatings is slight, the friction coefficients almost unchange with the increase of temperature; In the mixed regime and slip regime, Compound coating steady state friction coefficients rise with the temperature to present to come down trend , the temperature of substrate steady state friction coefficients effect is not obvious, coating 200℃wears amounts maxima away , and competing with substrate wears amounts away 1/3 .The wear mechanisms of coating are abrasive wear and delamination, delamination and oxidation wear at 200℃while exit delamination ,oxidation wear and abrasive wear.2. Normal loading change has very big effect to declining to move wear. The trend steady state friction coefficients are increased with normal loading assuming lessening wears amounts away obviously, following normal loading to increase by enhancing. Displacement amplitude is comparatively small to friction coefficients, displacement amplitude enhances, the amounts wearing away enhance under identical temperature condition. When coating has not worn through, the friction coefficients and wears amounts are lower than the titanium alloy obviously,the composites coatings shows excellent abrasion resistance. Friction coefficients are different time the different temperature, 25℃till 400℃temperature siding-to-siding blocks, steady state friction coefficients are maximal time 200℃, the amounts wearing away are maximal.3. The substrate also shows explicit influence on the fretting wera of high temperature. In the partial slip regime, the wear of PIII&D TiN/Ti composites coatings is slight, the friction coefficients of stainless steel substrate are smaller than titanium alloy substrate,and all is smaller than each substrate materials; In the slip regime, steady state friction coefficients rise with the temperature to present to come down trend , the wears amounts maxima away at 200℃, The wear mechanisms of stainless steel substrate coating are delamination and oxidation wear at high temperature. The abrasion resistance of composites coating of titanium alloy substrate are better than stainless steel substrate.