Vätgasutvecklande nickelelektroder : Vätningens inverkan vid beläggning med metallkloridbaserad lösning på nickelytor.

Sammanfattning: The production of hydrogen gas might be a part of the transition towards renewable fuels. Hydrogen can be used as fuel, electricity or heat with the help of an energy converter. In the production of hydrogen gas, electrolysis is usually used, which means that water is split into hydrogen and oxygen. Permascand AB in Ljungaverk is one of the world leaders in the production of electrodes and equipment for the electrochemical process industry and water treatment. One product that Permascand produces is hydrogen-developing cathodes, which is a nickel substrate coated with a metal chloride-based solution. In order for these cathodes to have long a service life and as uniform a quality as possible on the finished metal oxide coating, the coating solution must wet the substrate sufficiently. The purpose of the study is to investigate how different pre-treatments of the substrate affect the wetting of the surface. The wetting is measured with contact angle measurements and the various pre-treatments are pickling with HCl, blasting and pre-oxidation in the oven. These pre-treatments are varied and combined to see how they affects wetting.   The results show that with pickling alone, the temperature of the pickling bath has the greatest effect on the contact angle compared to the concentration and time. Combining pickling and blasting gives a contact angle of over 120 ° which is not desirable for coating work. Pre-oxidizing a sample in 30 or 60 was found to be able to lower the contact angle from 120 ° for a sample that was both blasted and worked to a contact angle of 82 ° and 73 °, respectively.   Pre-treated samples are also affected by a time aspect from the time the sample is processed until it is coated. The result of a completed time study shows that the contact angle of a sample deteriorates at most for the first eight hours.