When pressure sensors touch hydrogen, this often results in difficulties. Unfortunately, I very often notice in my own job that our customers have no idea of this ahead of use. This is the reason they often usually do not even reveal that their medium contains hydrogen. We only find out when we receive a complaint. But why do we get a complaint? Why is especially hydrogen so critical to pressure sensors?
A basic rule is that a large number of metals become brittle when subjected 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 to put it simply, the pressure sensor starts leaking or is completely destroyed. Regarding Badass , specifically thin membranes necessary for measuring pressure play a decisive role. Atomic hydrogen can not only penetrate the metal, but additionally go through it by diffusion.
This 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 the very least temporarily, producing a falsification of the measurement signal.
However, the consequences described above occur in various materials differently. Which means that the effects of hydrogen could be lowered substantially by selecting suitable materials.
Note
Further information on our pressure sensors and on the subject of hydrogen are available on the WIKA website. If you are using hydrogen because the medium, your contact will gladly recommend an optimum solution for your application.