Development of nitride and DLC coatings for high performance milling of CFRP products

Abstract

Currently, much attention in the aviation industry is paid to carbon-fiber-reinforced polymers (CFRP), which are superior in physical and mechanical properties to traditional materials used in the manufacture of aircraft airframe parts. CFRP cutting is associated with significant tool abrasion. Three coatings have been developed to improve the wear resistance of CFRP end mills. The DLC coating is a multilayer structure with an adhesive layer (Cr,Al,Si)N, a first transition layer (Cr,Al,Si)N with a high silicon content, a second transition layer DLC with a high silicon content and a wear-resistant DLC layer. The Zr-ZrN-(Zr,Cr,Al)N coating includes a Zr adhesion layer, a ZrN transition layer and a (Zr,Cr,Al)N wear-resistant layer having a nanolayer structure. The Ti-TiN-(Ti,Al,Cr)N coating also has three functional layers - an adhesive Ti layer, a transition layer (Ti,Al)N and a wear-resistant layer (Ti,Al,Cr)N having a nanolayer structure. The presence of adhesive and transition layers ensures strong adhesion to the substrate, as well as a smooth transition of properties between the substrate and the wear-resistant layer itself. As a result of the study of the power parameters of milling and the intensity of wear when machining with an uncoated tool and with developed coatings, it was found that the most favorable changes in the power parameters of cutting and wear resistance when milling a CFRP product are observed in tools with a DLC coating and Zr-ZrN-(Zr,Cr,Al)N. Analysis of the wear pattern of cutting tools with developed coatings shows noticeable signs of cutting edge wear for uncoated and Ti-TiN-(Ti,Al,Cr)N -coated tools. DLC and Zr-ZrN-(Zr,Cr,Al)N coated tools show no noticeable wear.