Ni-P Coatings as Hydrogen Permeation Barriers – A Review 

This review provides an overview of the hydrogen permeation mechanism, on the analytical methods employed to evaluate the performance and to describe the production and properties of electroless Ni-P coatings with a focus on application as hydrogen permeation barriers. The electroless Ni-P coatings deposited on steel coatings have been used so far for their anti-corrosion and wear properties; they are currently of interest due to their low hydrogen permeability. The simplicity of production and the possibility of achieving a homogeneous coating, regardless of the geometry of the substrate, make the electroless deposition process of the Ni-P alloy a candidate for ‘in situ’ applications in existing pipelines.