Corrosion protection of steel with multilayer coatings: Improving the sealing properties of physical vapor deposition CrN coatings with Al2O3/TiO2 atomic layer deposition nanolaminates

•Atomic Layer Deposition (ALD) was applied to seal pinholes in CrN coating.•Two orders of magnitude decrease in corrosion current density was obtained.•Sealing of pinholes in CrN coating was shown by Focused Ion Beam cross-sectioning.•Plasma pre-treatment was shown to improve adhesion and corrosion protection of ALD.•ALD deposition on dental steel curettes for corrosion protection was demonstrated.

Atomic Layer Deposition (ALD) of Al2O3/TiO2 nanolaminate was applied to improve the sealing properties of CrN coating deposited with Physical Vapor Deposition (PVD) on high speed steel (HSS). The corrosion protection properties were explored with Linear Sweep Voltammetry and visual estimation. Nearly two orders of magnitude decrease in corrosion current density was obtained by applying plasma pre-treatment prior to ALD coating. Sealing of CrN pinholes was shown with Focused Ion Beam/Scanning Electron Microscope technique. The effect of the ALD deposition parameters to adhesion of the ALD coatings was investigated with Rockwell indentation and microscope analysis. Thickness and refractive index of the ALD coatings were measured with ellipsometry, and density and roughness of the ALD coatings were investigated with X-Ray Reflectivity measurements. Neutral Salt Spray testing was used to investigate the corrosion resistance of PVD/ALD nanolaminates on HSS dental curettes.