Hydrogen and pressure sensors ? What should be observed?

When pressure sensors touch hydrogen, this often results in difficulties. Unfortunately, I very often notice in my own job that our customers are not aware of this prior to use. This is the reason 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? How come especially hydrogen so critical to pressure sensors?
A basic rule is that numerous metals become brittle when exposed 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 totally destroyed. In the case of pressure sensors, in particular thin membranes required for measuring pressure play a decisive role. Atomic hydrogen will not only penetrate the metal, but also go through it by diffusion.
It has several effects: When piezoresistive measuring principles are used, 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 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 technique leads to a detuning of the bridge at least temporarily, resulting in a falsification of the measurement signal.
However, the effects described above occur in various materials differently. Because of this the consequences of hydrogen could be lowered substantially by selecting suitable materials.
Note
ไดอะแฟรม on our pressure sensors and about hydrogen can be found on the WIKA website. If you use hydrogen because the medium, your contact will gladly recommend an optimum solution for your application.

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