Empowering PVD for corrosion protection

Abstract

A novel, monolithic DC‐magnetron sputtered TiN+MgGd coating, only 3to5 μm thick, effectively protects steel substrates from corrosion. This achievement is due to alloying of TiN with MgGd, which not only maintains the renowned wear resistance of TiN coatings, but potentially improves it through optimized deposition parameters.The key to the enhanced corrosion resistance lies in the addition of magnesium (Mg) and gadolinium (Gd). It reduces the coating's free corrosion potential, thereby mitigating the driving force for galvanic corrosion between coating and substrate. Moreover, at specific Mg to Gd ratios, a cathodic protection effect can be observed. Crucially, the presence of Gd is essential for this performance. It imparts hydrophobicity to the coating surface, reinforces a passivating layer and significantly enhances defect tolerance.This discovery paves the way for a sustainable alternative to electroplated chromium or combined electroplating and PVD, offering superior corrosion protection with minimal coating thickness.