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 job our customers are not aware of this ahead of use. This is why they often usually do not even reveal that their medium contains hydrogen. Amp learn when we get a complaint. But why do we get 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. Timely 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 required 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 consequences described above occur in various materials differently. Because of this the effects of hydrogen could 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 as the medium, your contact will gladly recommend an optimum solution for your application.

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