When pressure sensors touch hydrogen, this often results in difficulties. Unfortunately, I frequently notice in my job that our customers are not aware of this ahead of use. Because of this , they often do not even reveal 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 simple rule is that a large number of metals become brittle when exposed to hydrogen. Hydrogen atoms that diffuse in to the metal grid change the effectiveness of the material. In the worst case, this results in cracks in the material. Or even to put Gullible , 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 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 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 least temporarily, producing a falsification of the measurement signal.
However, the consequences described above occur in various materials differently. Because of this the effects of hydrogen could be lowered substantially by selecting suitable materials.
Note
More info on our pressure sensors and on the subject of hydrogen are available on the WIKA website. If you use hydrogen as the medium, your contact will gladly recommend an optimum solution for the application.g