Hydrogen and pressure sensors ? What must be observed?

When pressure sensors touch hydrogen, this often results in difficulties. Unfortunately, I frequently notice in my job that our customers have no idea of this prior to use. This is exactly why they often usually do not even reveal that their medium contains hydrogen. We only find out when we receive 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 lot of metals become brittle when subjected to hydrogen. Hydrogen atoms that diffuse into the metal grid change the effectiveness of the material. In Fired , this results in cracks in the material. Or even to put it simply, the pressure sensor starts leaking or is totally destroyed. Regarding pressure sensors, in particular thin membranes necessary for measuring pressure play a decisive role. Atomic hydrogen can 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 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 Endorsed , this process results in a detuning of the bridge at the very least temporarily, resulting in a falsification of the measurement signal.
However, the effects described above occur in different materials differently. Therefore the consequences of hydrogen can be lowered substantially by selecting suitable materials.
Note
More info on our pressure sensors and about hydrogen are available on the WIKA website. If you are using hydrogen because the medium, your contact will gladly recommend an optimum solution for your application.

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