| Abstrakt: |
The corrosion resistance of two multilayered metallic/ceramic coatings deposited from a 50:50 vol.% CrAl target, with a-CNx top layer deposited by High Power Impulse Magnetron Sputtering (HIPIMS) onto A11 tool steel was studied. The CrAl/CrAlN multilayer coatings with, and without a-CNx top layer, characterized by FE-SEM resulted in two different layers thicknesses of 1.5 and 1.2 µm, respectively. A glassy-like morphology was observed in the CrAl layer and in the CNx top layer, whereas the CrAlN layers exhibited a columnar morphology. XRD-analysis revealed a CrAlN FCC structure (111), accompanied of a Cr phase (110). Raman spectra for the CNx top layer, showed the characteristic peaks of G (Graphitic) and D (Disorder) for molecular vibrations in a-CNx containing thin films. Peaks were located between 1200 and 1700 cm−1. XPS results, on the other hand, showed the characteristic peaks for Cr, Al, N, present in both coatings. The deconvoluted peaks agreed with Cr2p3/2, Al2p, and N1s binding energies, respectively; besides; XRF analysis confirms the bulk chemical composition of these coatings. The electrochemical impedance, and potentiodynamic polarization tests in a 3.5 wt.% NaCl solution, displayed an improvement in the corrosion resistance for a-CNx top layer, and up to 15 times in Rp values compared to AISI A11 substrate. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink