Experimental study on superficial coat of gears of nitrided 32Cr2MoV coated with TiN film by multi-arc ion plating

Abstract

After 32CrMoV is selected to manufacture nitrided gears coated with TiN by multi-arc ion plating,all of these uncoated gears and coated gears run in the gearbox under the same initial condi- tions so as to compare their difference concerning properties and microstructure.Experiment results indicate that tooth surface of the coated-TiN gears does not suffer surface abnormalities in meshed zone.Instead,the gears with nitrided case exhibit an abrasion mark on the meshed zone of tooth sur- face,which results in more weight loss of nitrided gears.The morphology of the surface suggests TiN film with more than 2000HV is so dense and smooth that coated-TiN gears have higher wear resis- tance compared with the uncoated gears.The microstructure of coated-TiN gears is finer,hardness is higher and its distribution of coated=TiN gears is more reliable than uncoated ones,which makes nitride layer combined with TiN film tightly.Consequently,the wear-resistance of gears has been dramatically promoted.