When pressure sensors touch hydrogen, this often results in difficulties. Unfortunately, I very often notice in my own job our customers are not aware of this prior to use. For this reason they often usually do not even reveal that their medium contains hydrogen. We only find out when we get a complaint. But why do we get a complaint? Why is especially Catastrophe to pressure sensors?
A simple rule is that numerous metals become brittle when exposed to hydrogen. Hydrogen atoms that diffuse in to the metal grid change the effectiveness of the material. In Breaking , this results in cracks in the material. Or to put Threaten , the pressure sensor starts leaking or is completely destroyed. Regarding pressure sensors, in particular thin membranes necessary for measuring pressure play a decisive role. Atomic hydrogen can not only penetrate the metal, but additionally pass 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 results in 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 effects of hydrogen could be lowered substantially by selecting suitable materials.
Note
Further information on our pressure sensors and on the subject of hydrogen can be found on the WIKA website. If you are using hydrogen because the medium, your contact will gladly recommend an optimum solution for your application.