Corrosion resistance of duplex and gradient CrNx coated H13 steel

• Published in: Applied surface science Vol. 211; no. 1-4; pp. 293 - 299
• Main Authors: ZHOU, Q. G, BAI, X. D, CHEN, X. W, PENG, D. Q, LING, Y. H, WANG, D. R
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 30.04.2003
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Corrosion protection; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals. Metallurgy; Physics; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surface treatments; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Scanning electron microscopy; Chromium nitrides; Surface coating; Chromium nitride; H13 steel; XRD; Surface composition; Electrochemical behavior; Surface structure; Corrosion resistance; Potentiodynamic method; Cathodic arc deposition; Steels; Microstructure; Gradient coating; X-ray photoelectron spectra
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/s0169-4332(03)00254-x

The electrochemical behavior of H13 steel coated with duplex and gradient CrNx coatings deposited by cathodic arc deposition has been studied. The substrate material was coated with CrN by cathodic arc deposition technique. Duplex layers of CrNx which normally include an interlayer approximately 100-200 nm of Cr under the main CrN coating, were prepared; gradient CrNx coating were produced with continuous elevated nitrogen pressure. The X-ray photoelectron spectroscopy (XPS) was applied to characterize the chemical composition, and the glancing angle X-ray diffraction (GAXRD) was used to examine the crystallographic structure. The potentiodynamic polarization was examined by Zahner IM6e electrochemical workstation in a 0.5 M H2SO4 solution at ambient temperature, and the corrosive surface was detected by scanning electron microscopy (SEM). It was shown that the gradient coating could enhance the corrosion performance of CrNx coated H13 steel. The corrosion resistance improvement was not only attributed to the increase in thickness, but also to the internal microstructure and phase composition. Gradient CrNx. coating produced in this work was proved to be particularly promising in terms of corrosion resistance, owing to its incontinuous pinholes and different composition: Cr, Cr2N in inner part and CrN in surface. The results showed that the gradient coating had an improved electrochemical performance than duplex CrN coating.