Need to test the corrosion resistance of your material or a protective coating?
In collaboration with the University of Tartu we can do both chemical and electrochemical tests to simulate real or even extreme conditions in order to evaluate the performance of your sample.
Contact us if you are interested in corrosion testing!
Chemical tests – Studied substrates are exposed to a corrosive environment similar to the real conditions where it will be used later on. We can also alter the conditions of the environment to make it more corrosive by adjusting the pH and temperature or include UV light. A common example would be a test of series to compare the quality of stainless steel samples obtained from different suppliers. Another example would be the evaluation of different protective coatings on metal substrates.
Electrochemical tests – Corrosion can electrochemically be accelerated and this allows to quickly obtain reliable information about a materials or protective coatings corrosion resistance. For instance, certain metal alloys can be immersed in a salty water for years before it corrodes while electrochemically we can evaluate its long-term performance within a hour.
Microscopy – In addition to corrosion tests we also do microscopy studies of the tested substrates in order to get additional information about the type of corrosion. For example, Pitting corrosion often occurs undetected as it stats as a tiny hole on the surface and forms a network of tunnels inside the substrate, thus greatly degrading its mechanical properties. In contrast, uniform corrosion initially affects the aesthetic appearance of a material and mechanical properties are not much affected if the problem is dealt with.
Hydrogen is the most abundant substance in the universe. It fuels the starts that light the nightsky. Hydrogen will also power the future of mankind as it is already used as car fuel and within this century even in fusion reactors.
As most of you know, a water molecule consists of one oxygen atom and two hydrogen atoms. So in order to get hydrogen, it is needed to split the water molecule. This can be done for example electrochemically where an electrical potential is applied between electrodes in a salt water. For a home experiment one can simply put a 9 V battery into salt water and watch how hydrogen bubbles start to form at the cathode. At the same time oxygen is generated at the anode but since the anode on the battery is usually made of steel, it will quickly corrode as it reacts with chlorine and oxygen. This causes the salt water to go brown. So instead, you may want to use electrodes instead that are connected to an external power source. If a DC voltage is used then especially the anode needs to be made from a chemically inert conductive material such as platinum which doesnt oxidize. At this anode oxygen gas can be collected. At the same time hydrogen gas is generated at the cathode and can also be collected. If DC voltage is used then the electrode at cathodic potentials will not corrode very quickly as oxidation cannot occur. However hydrogen damage may eventually destroy the electrode.
Hydrogen damage occurs when the small atomic hydrogen generated at the cathode moves into pores and cracks inside the electrode and combines with other hydrogen atom to form molecular hydrogen. The molecular hydrogen however is too large to diffuse through metal and starts building up inside the sealed crack or pore and pressure increases until it splits the material.
In order to produce as much gas as possible, the surface area of electrodes needs to be increased. Make the electrodes rough, multilayered or highly porous for greater surface area.
If AC voltage is used to split water, then corrosion is suppressed and for some time even stainless steel can be used as both electrodes.
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