Research On High Temperature Fretting Wear Of Ti-Al-Zr Titanium Alloy And WC-12Co Plasma Spraying Coatings

Fretting wear is a familiar and prevalent wear form in Engineering. Fretting wear is a phenomenon that can't be avoided in the equipment of Nuclear Power. Quite a few damages in Nuclear Power Engineering correlate to fretting wear, such as the fretting damages in steam generator tube and Zircaloy-4 tube. The equipments of Nuclear Power are working in the condition of high temperature. Investigation on the high temperature fretting wear will redound to alleviate damages in the equipment of Nuclear Power, which has important theory significance and great economic benefit.High temperature fretting wear behavior of Ti-Al-Zr titanium alloy and WC-12Co plasma spraying coatings have been studied using high precision fretting wear test apparatus. Various analysises, measurements of wear volume and observations of the wear scar pattern have been carried out by means of Optical Microscopy (OM), X-ray Diffractometer (XRD), Laser Confocal Scanning Microscopy (LCSM), Scanning Electron Microscopy (SEM) and Energy Dispersion Spectrometer (EDS). The effects of displacement (10N～100N), normal load (10N～100N) and temperature (room temperature～400℃) have been focused on. The mechanism of high temperature fretting wear is explored. The results are drawn as follows:1. Displacement and normal load have influence on wear volume and friction coefficient. With the increasing of the displacement and normal load, both the wear volume and the friction coefficient increase.2. Temperature has great influence on the fretting wear. The friction coefficient and the wear volume of Ti-Al-Zr titanium alloy at 200℃are at the most. The friction coefficient of WC-12Co plasma spraying coatings at room temperature is lower than that of WC-12Co plasma spraying coatings at 200℃and 400℃. The wear volume does not change with the temperature increasing.3. At 25℃and 200℃, the wear mechanism of Ti-Al-Zr titanium alloy is adhesive wear and abrasive wear, mainly delamination and abrasive wear at 400℃. Because of the particular delamination structure of plasma spraying coatings, the wear mechanism of WC-12Co plasma spraying coatings is mainly delamination and abrasive wear from 25℃to 400℃.4. From 25℃to 400℃, the friction coefficient of WC-12Co plasma spraying coatings is lower than that of Ti-Al-Zr titanium alloy; Because of high hardness and well high temperature capability of WC-12Co plasma spraying coatings, the wear volume of WC-12Co plasma spraying coatings is lower than that of Ti-Al-Zr titanium alloy. The WC-12Co plasma spraying coatings on Ti-Al-Zr titanium alloy improves the property of fretting wear resistant.