Microstructure analyses of CrN coating synthesized by a hybrid PVD and metal-plasma ion implantation process

Chromium nitride (CrN) coating is promising for precision forming and molding applications due to its superior tribological properties and environmentally friendly nature. In this study, enhancement of the surface properties of CrN, such as the density and wetting characteristics, were conducted with energetic ion implantation treatment. CrN coatings were deposited using a hybrid physical vapor deposition (PVD) and metal-plasma ion implantation (MPII) technique. MPII is a plasma-based ion implantation process based on an accelerated (10-80 keV) vacuum-are metal plasma source with multiple charge states. At the initial coating stage, low dosage of MPII ion flux helps in surface activation and ion mixing. Subsequently, surface treatments of the as deposited CrN coating with implantation of metal and/or carbon ions result in densification and phase transformation at a near-surface regime. The wear resistance, corrosion resistance, fatigue strength and mold-releasing mechanism are significantly improved. The surface study was followed by a series of microstructural and tribological analyses. (C) 2002 Elsevier Science B.V. All rights reserved.