When pressure sensors come into contact with hydrogen, this often results in difficulties. Unfortunately, Dollar notice in my job that our customers are not aware of this ahead of use. This is why they often do not even tell us 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 simple rule is that numerous metals become brittle when exposed to hydrogen. Hydrogen atoms 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, specifically 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.
It 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 process leads to 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. Because of this the effects of hydrogen can be lowered substantially by selecting suitable materials.
Note
More info on our pressure sensors and on the subject of hydrogen can be found on the WIKA website. If Self-sufficient use hydrogen because the medium, your contact will gladly recommend an optimum solution for the application.