The Research On The Friction And Wear Properties Of Al₂O₃ And DLC PCVD Coating

The tool is the consumable and the pivotal accessory of machine, the surface performance of which attracts most attention of experts for its importance in the whole machine. Currently, the main surface strengthens treatment technology for the carbide tool is depositing TiN, TiC and other coats by Chemical Vapor Deposition. As the extra-hard coat, the DLC film not only has the high hardness, but also has the small friction coefficient; Al₂O₃ coat has good mechanics, physical property, such as the high hardness, wear resistance, good stability in high temperature and excellent chemical stability, they are both ideal antifriction and wear resistance coats. The investigation is on friction wear behavior of both coats in different situations, and started from preparation of DLC films and Al₂O₃ coat on the carbide tool.The results of the experiments show: (1)In certain loading and sliding velocity, the friction coefficient of DLC film is dropping along with loading increasing, and also dropping along with the sliding-velocity increasing; DLC films have good antifriction and wear resistance performance in low loading and high sliding-velocity situation. (2)In certain loading and sliding velocity, the friction coefficient of Al₂O₃ coat is dropping along with loading increasing, and also dropping along with the sliding-velocity increasing; Al₂O₃ coat have good antifriction and wear resistance performance in low loading and high sliding-velocity situation. (3)Lubricating water and lubrication could both reduce friction coefficient and the wear rate effectively comparing with the experiments without lubricant, and the effect in lubrication situation is much better than in the water lubricating situation. In the situation of water lubricating and lubrication, DLC films and Al₂O₃ coat both can reduce the wear rate of tool.And the effect of DLC films are much better. (4)In respect of the factor in affecting friction coefficient, the situation of experiments is the most important factor, and the loading is the most unimportant factor; in respect of the factor in affecting wear rate, the type of the coat is the most important factor, and the loading is the most unimportant factor.Considering from coat antifriction performance, the friction coefficient of Al₂O₃ coat has the smallest in the 150r/min sliding velocity and 40N loading lubrication situation. Considering from coat wear resistance performance, DLC film has the lowest wear rate in the 150r/min sliding velocity and 40N loading lubrication situation.