Hydrogen Permeation Instrument

The electrochemical hydrogen permeation technique was introduced by Devanathan and Stachurski in 1962. The technique has been implemented in ISO 17081.

The operation principle of the technique is based on the hydrogen diffusion through a metallic membrane specimen that separates two cells: a charging cell and a monitoring cell. Hydrogen is created in the charging cell electrochemically or in a corrosion process. One can also pressurise the charging cell with high-pressure gaseous hydrogen. The hydrogen flux diffuses through the membrane specimen in the monitoring cell, where it is oxidised electrochemically in an alkaline environment. The measured current corresponds to the amount of hydrogen diffused through the metallic membrane.

Devanathan cells are widely available for the ambient environment. Cormet’s Devanathan cell operates at high temperature and pressure. If one wants to study the effect of stress on the hydrogen permeation, one can even apply a tensile stress on the specimen.

Both the charging and the monitoring cell must operate at the same pressure. Otherwise, the thin membrane specimen would plastically deform and eventually break. Cormet provides the needed instrumentation to minimise the pressure difference between the two cells.