Corrosion-resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

• Highly corrosion resistant composite TiN layers were produced on AZ91D Mg alloy.
• The corrosion resistant TiN composite layers were produced using a hybrid method.
• The hybrid treatment combines the PVD methods with a final chemical-type tightening.
• The final tightening of the TiN composite layers is crucial for high corrosion resistance.
• The TiN composite layers on AZ91D alloy give a corrosion potential shift of 1300 mV.

The aim of the present study was to develop the hybrid method which allows producing highly corrosion-resistant composite titanium nitride layers on the AZ91D magnesium alloy. The hybrid method combines the deposition of composite titanium nitride layers using the PVD methods with the final tightening of the layers by a simple chemical-type treatment. The tightened multilayer obtained by the hybrid treatment is composed of a TiN surface layer and an aluminum sub-layer diffusively bonded with the substrate, separated by a thin transition titanium sub-layer. The effect of the composite titanium nitride layers on the corrosion resistance of the AZ91D alloy was examined by electrochemical methods. The results of the examinations show that the hybrid method yields an outstanding improvement of the corrosion resistance manifested by the corrosion potential shift by about 1300 mV. The tightening of the composite titanium nitride layers plays the crucial role in achieving this significant improvement of the corrosion resistance.