Hydrogen and pressure sensors ? What should be observed?

When pressure sensors touch hydrogen, this often results in difficulties. Unfortunately, I frequently notice in my job our customers have no idea of this prior to use. Because of this , they often usually do not even reveal that their medium contains hydrogen. We only learn when we get a complaint. But why do we get yourself a complaint? Why is especially hydrogen so critical to pressure sensors?
A simple 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 even to put it simply, the pressure sensor starts leaking or is completely 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 also go through it by diffusion.
It 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 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 effects described above occur in various materials differently. This means that the consequences of hydrogen could be lowered substantially by selecting suitable materials.
Note
Shrewd 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.

Leave a Comment