When pressure sensors touch hydrogen, this often results in difficulties. Unfortunately, I very often notice in my job that our customers have no idea of this prior to use. This is why they often do not even reveal that their medium contains hydrogen. We only find out when we get a complaint. But why do we get yourself a complaint? Why is especially hydrogen so critical to pressure sensors?
A basic rule is that a large number of metals become brittle when subjected to hydrogen. Hydrogen atoms that diffuse in to the metal grid change the strength of the material. In the worst case, this results in cracks in the material. Or even to put it simply, the pressure sensor starts leaking or is completely destroyed. Regarding pressure sensors, in particular thin membranes required for measuring pressure play a decisive role. Atomic hydrogen will not only penetrate the metal, but additionally go through it by diffusion.
This has several effects: When piezoresistive measuring principles are used, it becomes critical if hydrogen reacts with the inner transmission medium or accumulates there. This initially only falsifies the measurement results, but can later on also lead to complete destruction of the sensor in individual cases. The addition of hydrogen also changes the instrumentation characteristics of the resistance structures of the measurement bridge of thin-film sensors. Despite being reversible, this process leads to a detuning of the bridge at the very least temporarily, resulting in a falsification of the measurement signal.
However, the consequences described above occur in various materials differently. Because of pressure gauge 10 bar of hydrogen can be lowered substantially by selecting suitable materials.
More info on our pressure sensors and on the subject of hydrogen can be found on the WIKA website. If you are using hydrogen because the medium, your contact will gladly recommend an optimum solution for the application.