Tribological and Corrosion Properties of Cr-Zr-N Coatings

Abstract

Tribological and Corrosion Properties of Cr-Zr-N Coatings Gwang-Seok Kim, Young-Su Kim, Sung-Min Kim and Sang-Yul Lee Department of Materials Engineering, Korea Aerospace University, Koyang 412-791 Kwang-Ryeol Lee Computational Science Center, Future Convergence Technology Lab., Korea Institute of Science and Technology, Seoul 130-650 (Received 16 June 2008) In this work, ternary Cr-Zr-N coatings with not only much improved mechanical properties but also a very low surface roughness were synthesized by closed eld unbalanced magnetron sputtering with vertical magnetron sources and their tribological properties under the various relative humidity (RH) conditions were investigated. Especially, in the case of the Cr1 xZrxN coating with x = 0.34, its friction coe cient obtained under a 90 % RH environment was compared with that of DLC(diamond like carbon) lms measured under the same conditions. In addition, to evaluate the corrosion behavior of the coatings, we carried out potentiodynamic polarization tests in a deaerated 3.5 wt.% NaCl solution at 40 C and we compared the results with those obtained from CrN lms. The tribological behaviors of the Cr-Zr-N coatings did not seem to be signi cantly a ected by the humidity of the air. Under a 90 % RH environment, the average friction coe cient of the Cr1 xZrxN coating with x = 0.34 against a steel ball was approximately 0.17 and this value was lower than those of the CrN (0.49) and DLC (0.2) lms. In the potentiodynamic polarization test results, we found that the corrosion resistance of the Cr-Zr-N coatings was signi cantly improved in comparison with that of CrN and that their corrosion current density (icorr) and corrosion rate decreased with increasing Zr content (x value). PACS numbers: 62.20.Qp, 68.35.Ct, 68.55.Jk