Determination of hydrogen diffusivity in nickel by subsurface microhardness profiling

Hydrogen diffusivity was estimated in pure Ni at ambient temperature using the technique of subsurface microhardness profiling after cathodic hydrogen charging. Hydrogen was charged utilizing sulphuric acid of three different strengths. The estimated average hydrogen diffusivity (7.6×10−14 m2 s−1) was within the range of published hydrogen diffusivities in nickel at 303 K (1.7×10−14–10.5×10−14 m2 s−1). It was shown that determination of hydrogen diffusivities in metallic materials by subscale microhardness profiling is a versatile technique that can be used to obtain hydrogen diffusivities with simple experimentation.