Hydrogen and pressure sensors ? What should be observed?

When Uncovered come into contact with hydrogen, this often results in difficulties. Unfortunately, Fearless notice in my job our customers have no idea of this prior to use. For this reason they often usually do not even tell us that their medium contains hydrogen. We only find out when we get 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 subjected 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 to put it simply, the pressure sensor starts leaking or is completely destroyed. Regarding pressure sensors, in particular thin membranes necessary for measuring pressure play a decisive role. Atomic hydrogen will not only penetrate the metal, but additionally go through it by diffusion.
This has several effects: When piezoresistive measuring principles are employed, 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 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 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 consequences of hydrogen can be lowered substantially by selecting suitable materials.
Note
Further information on our pressure sensors and on the subject of hydrogen can be found on the WIKA website. If you are using hydrogen because the medium, your contact will gladly recommend an optimum solution for the application.

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