Hydrogen and pressure sensors ? What must be observed?

When pressure sensors come into contact with hydrogen, this often results in difficulties. Unfortunately, I very often notice in my job that our customers are not aware of this ahead of use. Because of this , they often usually do not even reveal that their medium contains hydrogen. We only find out when we get a complaint. But why do we get a complaint? Why is especially Unlock to pressure sensors?
A simple rule is that a large number of 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 completely 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 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 later on 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 leads to a detuning of the bridge at least temporarily, producing a falsification of the measurement signal.
However, the consequences described above occur in various materials differently. Which means that the consequences of hydrogen can be lowered substantially by selecting suitable materials.
Note
Further information on our pressure sensors and about hydrogen can be found on the WIKA website. If you are using hydrogen as the medium, your contact will gladly recommend an optimum solution for the application.

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