TiN Coating Study Of Friction And Wear

Cylinder-piston ring as one of the most important friction in the internal combustion engine have a great impact on the engine’s power, reliability and durability. Cylinder-piston ring liner wear directy impact the work of the engine,which often cause part of the fuel directly transpiration without exclusion and an increasing of automobile exhaust pollution levels. Cylinder-piston ring friction also affects the mechanical efficiency of the engine.Therefore in order to study the wear resistance of paired associate, then the best materials of wear resistance will be optimized for the next engine cylinder-piston ring manufacturing, improve engine efficiency, energy saving and emission reduction. In this study, the operation of internal combustion engine has been simulated by the tribology systems guiding ideology and wear conditions-form simulation principles. Experiment is conducted by homemade reciprocating friction and wear tester under different load(20MPa,30MPa,40MPa,50MPa,60MPa),temperatures (120℃,150℃, 180℃) conditions, using TiN Cylinder liner and PVD Piston rings as the paired associate and achieve the following conclusions:1、As the increase of load, The friction coefficient between the TiN coating cylinder liner of 40Cr and PVD ring substrate20MPa-30MPa are presented rising.30MPa-50MPa goes down,50MPa-60MPa has almost no change, the friction coefficient increases most significantly at the first time, then goes down regular, and has no change at last.2、Friction with the increase of the load grows almost linearly. And each temperature has the rules.3、TiN coating of the liner in the friction surface height does not change significantly,The wear volume is small that can hardly express. At 20MPa load surface have not been destroyed, and 60MPa load have a small part of the coating been damaged. To increase the load of PVD piston ring is very easy appearing the phenomenon of cylinder scoring.4、TiN coated cylinder of 40Cr substrate friction coefficient is dropping when the temperature is rising, low temperature has the maximum friction coefficient, the higher the temperature the lower friction coefficient.5、The variation of friction coefficient of the whole did not change much no matter what the changes in temperature or the load change, the friction coefficient transform is very small but regular.6、The coating better than most of other coating wearing a little in the work environment of high temperature but not great load is more perfect.