The Research On The Friction And Wear Properties Of TiN Coating And Its Mechanism

With high hardness, low friction coefficient, small differences in the thermal expansioncoefficient with steel and good performance in resistance to abrasion, TiN coating is widelyused for tools coating. The wear in the key parts of equipments is very serious, which hascaused a large number of economic loss. TiN coating is used as wear-resisting coating in thekey parts of equipments. However, because of the complexity in friction and wear process ofTiN coating, there is little research on friction and wear mechanism of TiN coating. In thissubject, TiN coating is deposited on the surface of the YG6alloy and45steel by the arc ionplating technology. Then test the friction and wear properties in different load and rotatingspeed, observe the friction phenomenon, and observe the surface morphology after wearing,analysis the friction and wear mechanism.The test results show that:(1) The friction coefficient of TiN coating on YG6surface isreduced by4%~21%than the matrix YG6. TiN coating on YG6surface reduces frictioncoefficient effectively.(2) The friction coefficient of TiN coating on45steel surface increasesby about20%. TiN coating on45steel surface can not reduces friction coefficient.(3) Withthe increase of the load, the friction coefficient of TiN coating on YG6and45steel surface isgradually decreased; Along with the increase of speed, the friction coefficient of TiN coatingon YG6and45steel surface decreases then increases.(4) With the increase of the load, thewear rate of TiN coating on YG6and45steel surface increases gradually; Along with theincrease of speed, the wear rate of TiN coating on YG6and45steel surface decreases thenincreases.(5) TiN coating of45steel surface is destroyed in high speed. friction coefficientappeared instantly increase in this time.In this Subject, observe the surface morphology after wearing of TiN coating, analysisthe friction and wear mechanism, draw the conclusion is as follows:(1) the wear mechanismof TiN coating on YG6surface is abrasive wear in low load, and local fatigue wear in the highload.(2) the wear mechanism of TiN coating on YG6surface is abrasive wear in the lowspeed, and local adhesion wear in high speed.(3) the wear mechanism of TiN coating on45steel surface is abrasive wear in low load, and local adhesion wear in the high load.(4) thewear mechanism of TiN coating on45steel surface is abrasive wear in the low speed, andserious adhesion wear in high speed. Meanwhile, analysis the bonding strength between TiNcoating and matrix, friction and wear behavior, set up some easy models, explain some testphenomenons.