Hydrogen plays a major role as a future energy carrier. Its properties and interactions with metals lead to material science challenges. Hydrogen barrier coatings are one possible solution. They reduce the amount of hydrogen penetrating into the underlying material to be protected and thus reduce the risk of hydrogen embrittlement. [1,2] This work examines the barrier effect of tungsten carbide coatings.

The tungsten carbide coatings shown were produced by magnetron sputtering. The focus was on thin layers with thicknesses in the range of 200 nm to 400 nm. The influence of the coating thickness was investigated. Furthermore, the influence of a bias voltage was examined at a layer thickness of 200 nm. A gas-driven hydrogen permeation setup and an electrochemical method were used to evaluate the barrier effect.

The high permeation reduction factors of up to 11,000 (maximum value for the 400nm layer) at a sample temperature of 200°C emphasized this result. The excellent barrier effect of the tungsten carbide coatings could be confirmed with the electrochemical permeation measurement method. In addition, the influence of the layer thickness and the bias voltage was clarified.

References
[1] N.-E. Laddel; International Journal of Hydrogen Energy, 2022, 47, 32707-32731.
[2] V. Nemanič; Nuclear Materials and Energy, 2019, 19, 451-457.