Research On Oxidation Properties Of TiAlSiN Hard Coatings Deposited By Magnetron Sputtering

TiN,TiAlN and TiAlSiN transition metal nitride coatings which are widely used as high hardness,wear-resisting,high-temperature oxidation resistance,have a large number of applications in tools,molds and decorative materials field.Based on the previous research,TiAlN with different Al content and TiAl SiN coatings with different Si content prepared by magnetron sputtering on high-speed steel substrare.And TiAlSiN coatings were heat treatment in vacuum and air.The phase structure of coatings were analyzed by using X-ray diffraction.The surface morphology and composition were characterized by scanning electron microscopy which equipped with EDS systems.The roughness was tested by laser scanning confocal microscope.The hardness of coatings were ebaluated by nanoindentation.Researching on the TiAlN coatings with different Al contents in phase structure,surface morphology and composition and hardness.Studying on the TiAlSiN coatings with different Si contents in phase structure,surface morphology and composition and hardness.Researching on phase structure,surface morphology,composition and nanohardness of TiAlSiN coatings before and after annealing in vacuum and air.Experimental results show that TiAlN keep face-centered cubic structure.The coatings surface roughness decreases with increasing Al contents.Hardness and elasticity modulus reach highest value in 16.81 GPa and 250.9GPa with power of Al target in 80 W.When Al target power reach 120 W,hexagonal phase Ti3Al2N2 formed.With regard to TiAlSiN,hardness of coatings rise first and fall with the Si content increased.The coating present the highest hardness and elasticity modulus hardness in26.43 GPa and 303.5GPa with Si content were 16.48 at.% as well as best properties resistance to plastic deformation.It consists of?Ti,Al?N /Si3N4 composite structure.The hardness of coatings will be decrease in excessively high ratio of Si because more Si3N4 formed.Coatings keep the initial phase structure and good thermal stability after vacuum heat treatment in 800??900??1000?.Stress relaxation is the main reason for decasing hardness.A lot of Al2O3 appeared after 800? atmosphere heat treatment.The surface dense,smooth.However,Ti,Al,Si element diffusion severely formed TiO₂ andTi₂O₃ after after 1000? atmosphere heat treatment.Surface became irregularity even dropped.The oxidation resistance decline rapidly.