Hydrogen and pressure sensors ? What should be observed?

When pressure sensors come into contact with hydrogen, this often results in difficulties. Unfortunately, I frequently notice in my job our customers are not aware of this prior to use. Because of Special , they often do not even reveal that their medium contains hydrogen. We only learn when we receive a complaint. But why do we get yourself a complaint? Why is especially hydrogen so critical to pressure sensors?
A simple rule is that numerous metals become brittle when exposed to hydrogen. Hydrogen atoms that diffuse into 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, specifically thin membranes necessary for measuring pressure play a decisive role. Atomic hydrogen can not only penetrate the metal, but additionally pass through it by diffusion.
This has several effects: When piezoresistive measuring principles are employed, it becomes critical if hydrogen reacts with the inner 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 process results in 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. This means that 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 Sadness are using hydrogen as the medium, your contact will gladly recommend an optimum solution for your application.

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