Dependence of Wear and Mechanical Behavior of Nitrocarburized/Crn/Dlc Layer on Film Thickness

Diamond-like carbon (DLC) films are amorphous metastable carbon form that provide interesting mechanical and tribological properties. The role of film thickness influence upon wear and mechanical properties is of interest and not yet fully reported. In this study, two samples of previously plasma nitrocarburized, quenched and tempered H13 steel were duplex treated. First, a physical vapor deposition (PVD) chromium nitride (CrN) layer was applied, followed by a top final diamond-like carbon layer applied by plasma-enhanced chemical vapor deposition (PECVD). To evaluate thicknesses influence on mechanical and wear properties of coatings, samples were treated using two different thicknesses of both layers. In this study, the thickest CrN and DLC case presented higher hardness and better tribological properties, however, its failure occurs in brittle fashion.

类金刚石碳（Diamond-like carbon, DLC）薄膜是一类非晶亚稳态碳材料，具备独特的力学与摩擦学性能。薄膜厚度对磨损与力学性能的影响备受关注，但目前尚未有全面的研究报道。本研究中，对两块预先经等离子体氮碳共渗、淬火回火处理的H13钢样品开展了复合处理：首先通过物理气相沉积（Physical Vapor Deposition, PVD）制备氮化铬（Chromium Nitride, CrN）层，随后再通过等离子体增强化学气相沉积（Plasma-Enhanced Chemical Vapor Deposition, PECVD）沉积顶层类金刚石碳层。为探究涂层厚度对其力学与磨损性能的影响，本研究采用两种不同厚度的CrN层与DLC层对样品进行处理。研究结果显示，厚度最大的CrN与DLC复合涂层具有更高的硬度与更优异的摩擦学性能，但该涂层体系的失效方式为脆性断裂。