Multiphase Cu-Ti Coatings coated by Plasma Vacuum-Arc deposition on Cu-Be Alloy С17200

Abstract

Introduction. Deposition of hard intermetallic coatings is an efficient technology to improve operating characteristics of Cu-Be alloys. PVD of coatings is widely used for surface engineering of constructive materials, deposition of wear and corrosion resistant surface layers. Multiphase and multicomponent coatings are considered as the most efficient hard coatings for surface engineering. In this research, Ti-Cu coatings are deposited by a vacuum-arc plasma-assisted method on hardened BrB2 bronze (alloy C17200) at a temperature of 320 – 330 oC. Processing resulted in ageing of Cu-Be alloy and surface hardening of material. The aim of the research is to analyze the microstructure, phase composition, and tribological properties of Cu-Be alloys modified with plasma-activated PVD coatings based on titanium, with the subsequent development of an effective technology for surface engineering and improvement of the mechanical properties of Cu-Be alloys. Results and discussion. Plasma-assisted PVD of Cu-Ti coatings on the surface of tempered C17200 alloy at 320 – 330 oC resulted in formation of multiphase coatings, consisting of Cu, Ti, CuTi and CuTi2 components. X-ray analysis revealed development of ageing process in Cu-Be alloy which resulted in formation of CuBe inclusions. Wear resistance of modified blocks is investigated. The main mechanism of modified blocks wearing is cracking of the coating with further formation of fine debris of base Cu-Be material. Wear debris is significantly smaller then debris of С17200 alloy without coating. Surface microhardness of blocks processed at 320 –330 oC is comparatively high (540 HV0.02 - 530 HV0.02). Wear resistance of blocks subjected to surface engineering is comparatively low probably because of small thickness of the coating (< 8 µm) and insufficient hardness of matrix material.