When Money touch hydrogen, this often results in difficulties. Unfortunately, I frequently notice in my job our customers are not aware of this prior to use. Because of this , they often usually do not even tell us that their medium contains hydrogen. We only learn when we get a complaint. But why do we get a complaint? How come 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 in to the metal grid change the strength 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, in particular thin membranes required for measuring pressure play a decisive role. Atomic hydrogen can not only penetrate the metal, but also 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 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 technique leads to a detuning of the bridge at the very least temporarily, resulting in a falsification of the measurement signal.
However, the consequences described above occur in different materials differently. This means that the consequences of hydrogen can 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 use hydrogen because the medium, your contact will gladly recommend an optimum solution for your application.