Hydrogen and pressure sensors ? What should be observed?

When pressure sensors come into contact with hydrogen, this often results in difficulties. Unfortunately, I very often notice in my own job our customers have no idea of this prior to use. This is exactly why they often usually do not even tell us that their medium contains hydrogen. We only learn when we receive a complaint. But why do pressure gauge octa 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 exposed to hydrogen. Hydrogen atoms that diffuse into the metal grid change the effectiveness 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 totally destroyed. In the case of pressure sensors, in particular thin membranes necessary for measuring pressure play a decisive role. Atomic hydrogen can not only penetrate the metal, but additionally go through it by diffusion.
It has several effects: When piezoresistive measuring principles are employed, it becomes critical if hydrogen reacts with the internal transmission medium or accumulates there. This initially only falsifies the measurement results, but can down the road also result in 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 technique leads to a detuning of the bridge at the very least temporarily, producing a falsification of the measurement signal.
However, the effects described above occur in various materials differently. Because of this the effects of hydrogen can be lowered substantially by selecting suitable materials.
Note
Further information on our pressure sensors and about hydrogen are available on the WIKA website. If you use hydrogen because the medium, your contact will gladly recommend an optimum solution for your application.