Waterstoffront

Waterstoffront, literally hydrogen front in Dutch, is a concept used in materials science and electrochemistry to describe the moving boundary that separates regions with differing hydrogen content within a material during diffusion and related reactions. The front marks where hydrogen concentration reaches a level that triggers a specific process, such as hydride formation or accelerated corrosion.

During charging or permeation, hydrogen atoms diffuse as interstitials through metal lattices. The gradient in chemical potential drives a front that advances with time. The front's speed and width depend on temperature, microstructure, trap density, and external driving forces such as applied current or loading. Trapped hydrogen at defects can slow or pin the front, while interfaces with oxide layers or phase boundaries can reflect or re-distribute it.

Waterstoffront is discussed in contexts such as hydrogen embrittlement of steels and nickel-based alloys, hydrogen storage materials where hydride phases grow from the front, or electrochemical systems including water electrolysis and fuel cells where hydrogen evolution and permeation create a moving boundary in thin films or membranes.

Measurement approaches include hydrogen permeation experiments, electrochemical permeation tests, neutron imaging, and mass spectrometry or microscopy techniques that resolve hydrogen distribution. Modeling often uses diffusion-reaction equations and front-tracking concepts, sometimes employing phase-field or finite-element methods to predict front position and related degradation.

Because the term is not universally standardized, waterstoffront is used primarily in qualitative discussions and regionally in academic literature. It remains a useful heuristic for understanding how hydrogen migration interacts with material structure to influence performance and failure in hydrogen-related technologies.