Influence of Al Content on the Microstructure and Properties of the CrAlN Coatings Deposited by Arc Ion Plating

摘要

Four Cr Al N coatings with various Al content were prepared by arc ion plating technology under different target currents.The effect of the Al content on the microstructure,chemical compositions,element chemical bonding states and mechanical properties of the Cr Al N coatings was analyzed.X-ray diffraction results show that the primary phase of the Cr Al N coating is fcc-(Al,Cr)N when the Al content is about 44.02 at.%.However,when the Al content increases to about 53.34 at.%,hcp-Al N phase emerges in the coating.And the hcp-Al N phase becomes the main phase in the Cr Al N coating with Al content of about 69.55 at.%.Cross-sectional images show that all the four coatings possess dense structures and the deposition rate of Al atom is higher than that of Cr atom.The hardness of the Cr Al N coating with Al content about 44.02 at.%is the largest(3149.72 HV)due to the solid solution hardening effect of the Al element.When the hcp-Al N phase is generated in the Cr Al N coating,the hardness declines.The tribological experiment shows that the wear resistance of the Cr Al N coating decreases gradually with increasing Al content when sliding against 100Cr6 steel ball.