Electrochemcial Characteristics of CrN Thin Films Prepared by Ion-Beam-Enhanced Deposition

摘要

It has been known that CrN ahs high hardness andhigh resistance against wear, oxidation and corrosion. Althoughmany studies have been done on its mechanical and hightemperature oxidation properties, studies on its electrochemicaland corrosion properties in aqueous solutions are still limited. Theaim of this study is to produce CrN thin films by ion-beam-enhanced deposition (IBED) and to make clear the corrosionbehavior of CrN by electrochemical measurements.CrN thin films were prepared by IBED under variousconditions and their polarization curves were measured in 1kmol·m-3 H2SO4 and 12 kmol·m-3 HCl. Changes in the surface ofthe thin films by polarization were examined by XPS and in-situ ellipsometry.The thin films prepared by IBED were composed of the largeamount of CrN and small amounts of Cr2N and Cr. The fraction ofCrN in the films increased with increasing flow rate of nitrogen.Potentiodynamic polarization curves exhibited that the activedissolution rate of the films decreased with increasing CrN contentof the films. The films with high CrN content showed excellentcorrosion resistance up to the start potential of transpassivedissolution without formation of passive films. That is, theexcellent corrosion resistance of CrN results from the intrinsicinactive nature of CrN surface.