The effect of MEVVA implanted Cr on the corrosion resistance of CrN coated low alloy steel by cathodic arc plasma deposition

Metal vapor vacuum arc (MEVVA) source implantation is a novel and profitable surface modification process. Cathodic arc plasma deposition of CrN coating has been applied on an industrial scale to improve the corrosion resistance of AISI 4140 steel. The effect of the Cr implanted by MEVVA (Cr/steel) on the corrosion behavior of CrN/steel through the surface modification was investigated. Both AISI 4140 steel and its coated assemblies of Cr/steel, CrN/steel and CrN/Cr/steel were evaluated in aerated 0.1 N HCl solution. The composition and structure of the MEVVA implanted Cr and cathodic arc plasma deposited CrN on steel were studied by X-ray diffraction and secondary ion mass spectrometer. The polarization resistance (R,) of all samples was measured and compared with d.c. polarization resistance and electrochemical impedance spectroscopy. The microstructure of corroded samples was also examined by scanning electronic microscopy and electron probe X-ray microanalyser. The results indicated that the corrosion resistance of CrN coated steel was significantly enhanced by the MEVVA implanted Cr in CrN/Cr/ steel. (C) 2003 Elsevier Science B.V. All rights reserved.