Tribological Characteristics Of Surface Microstructures In Water And Air

This project was granted by Natural Science Foundation- Key Program of Guangdong Union Foundation (U0934004), New Century Excellent Talents in University (NCET-10-068), Research Fund for the Doctoral Program of Higher Education of China (20093218110026), Natural Science Foundation of Jiangsu Province (BK2010074), Opening Funds of the State Key Lab. of Fluid Power Transmission and Control (GZKF-201009), Opening Funds of the state key laboratory of mechanical transmission (SKLMTKFKT201005).In this paper, four kinds of microstructures such as groove, meshwork, diamond, and square were fabricated using WEDM and EDM on the Ti alloy surface; Laser Surface Texturing (LST) was used to manufactured micro-dimple on the Ti alloy surface; then CrN and DLC coatings were deposited on the surfaces of microstructures by enhanced magnetron cathodic arc depositional system. The friction and wear properties of the microstructures surfaces and coupling surfaces sliding against Si3N4 ball in water when the load was 3N, sliding velocity was 0.4m/s. And the tribological characteristic of micro-dimples surface of Ultrasonic Motor stator was studied in here. The main researches and results are showed as fellows:Firstly, various area ratio diamond and square microstructure surfaces were studied in this paper, low friction characteristic was obtained when the width was 0.2mm and the area ratio was 30%. When diamond and square width was 0.25mm, surfaces of 10% area ratio showed low friction. The orthogonal experiment of groove microstructure surface demonstrated the area element had the strongest influence on tribological characteristic, when the depth element had minimal impact. For the dimple microstructure orthogonal experiment, element of dimple diameter was the principal factor to lower the friction coefficient of dimple microstructure surface, and the dimple area ratio was the main factor to affect the wear weight of dimple microstructure surface and the wear rate of ball. For the meshwork microstructure surface orthogonal experiment, we can include that the width was the main factor on the stable friction coefficient. The best result was got when the mesh angle was 45 and the interval-width ratio was 10.Secondly, the run-in process of various microstructure/CrN surfaces was extended. For the groove and meshwork microstructure/CrN surfaces, the friction coefficient and wear rate of Si3N4 ball were less than or equal to the smooth CrN surface, but the friction coefficient and ball wear rate of dimple microstructure/CrN surfaces were more than smooth CrN surface. The run-in process of groove or meshwork microstructure/DLC surface was shorter than that of dimple microstructure/DLC surface. The friction coefficients of three kinds of microstructure/DLC surfaces were less than or equal to the smooth DLC surface as the sliding distance increase, and the friction coefficient was reduced along with the width increase. The wear rates of balls were raised after the DLC coating was deposited on microstructure surface.Thirdly, micro-dimples were manufactured on Ultrasonic Motor stator surface, and tribological characteristic of these surfaces was studied in this paper. The micro-dimple surface with the dimple diameter of 0.15mm showed the excellent tribological properties, and its stable friction coefficient was 0.45 or so, the wear weight of stator tripled compared to untextured stator.