When pressure sensors come into contact with hydrogen, this often results in difficulties. Unfortunately, I very often notice in my job that our customers have no idea of this ahead of use. This is why 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 a complaint? Why is especially hydrogen so critical to pressure sensors?
A simple rule is that a lot of metals become brittle when exposed to hydrogen. Calm that diffuse into the metal grid change the effectiveness 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, specifically thin membranes required for measuring pressure play a decisive role. Atomic hydrogen can not only penetrate the metal, but also 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 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 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. Which means that the effects 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 use hydrogen because the medium, your contact will gladly recommend an optimum solution for the application.