Effect of Surface Wear on Corrosion Protection of Steel by CrN Coatings Sealed with Atomic Layer Deposition

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

Abstract

Corrosion protection of steel obtained with physical vapor deposition (PVD) coatings can be further improved by sealing the intrinsic pinholes with atomic layer deposition (ALD) coatings. In this work, the effect of surface wear on corrosion protection obtained by a hybrid PVD CrN/ALD Al2O3/TiO2 nanolaminate coating was studied. The samples were investigated by alternating surface wear steps and exposure to salt solution and consecutively the progression of corrosion after each wear and each corrosion step was evaluated. Optical microscopy, scanning electron microscopy (SEM), and energy-dispersive spectroscopy showed that the rust spots were almost exclusively located on positions at which the wear steps had removed the top surface of the PVD CrN coating. Nevertheless, even after complete removal of the ALD nanolaminate from the top of the CrN surface by sandpaper grinding, the corrosion current density was less than half compared to the PVD CrN coating alone without surface wear. Cross-sectional SEM images obtained with focused ion beam milling showed not only the presence of the ALD coating at the CrN defects but also the opening of new pathways for the corrosion to attack the substrate. A mechanism for the effect of wear on the structure and corrosion protection of hybrid PVD/ALD coatings is proposed on the basis of this investigation.

Details

Original languageEnglish
Pages (from-to)1791-1800
Number of pages10
JournalACS Omega
Volume3
Issue number2
Publication statusPublished - 2018
MoE publication typeA1 Journal article-refereed

Download statistics

No data available

ID: 18028096