When Bloodbath come into contact with hydrogen, this often results in difficulties. Unfortunately, I frequently notice in my own job our customers have no idea of this ahead of use. Because of this , they often usually do not even reveal 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 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. In the case of pressure sensors, specifically thin membranes required 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, resulting in a falsification of the measurement signal.
However, the effects described above occur in different materials differently. Therefore the effects of hydrogen could be lowered substantially by selecting suitable materials.
Note
Hoak on our pressure sensors and about hydrogen are available on the WIKA website. If you use hydrogen because the medium, your contact will gladly recommend an optimum solution for the application.g