Tag Archives: corrosion

How to Generate Hydrogen by Splitting Water

January 6, 2015Uncategorizedalternative, ampere, anode, automobile, car, cathode, chemical, chlorine, clean, corrosion, current, dollar, electric, electricity, electrochemical, electrochemistry, electrolysis, energy, environment, EUR, euro, experiment, experimental, free, fuel, fuel cell, fusion, fusion reactor, gas, generate, generator, global, global warming, green, H, H2, H2O, HHO, how to, hydrogen, hydrogen damage, oxygen, power, reaction, solar, USD, volt, voltage, water, water splittingCaptain Corrosion

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.

If you found this video useful, feel free to support me with 5 eur / usd via Paypal

← Back

Thank you for your response. ✨

How to Renew Tarnished Silver

June 12, 2014Uncategorizedcoin, corrosion, electrochemistry, hõbe, hõbeda poleerimine, jewelery, korrosioon, materials science, materjaliteadus, polish, renew, renew silver, renew tarnished silver, silver, silver polishing, silverware, tableware, tarnish, tarnished silverCaptain Corrosion

Silver, a valuable metal, has been used long time in making coins, tableware and jewelery. The metal surface however becomes tarnished within a few years and this is caused by corrosion as silver reacts with the surrounding environment.

The surfaces can be easily renewed with stuff available at home – all you need is water, aluminum foil, salt and soda.

Follow these steps to do it yourself:

1. Mix salt and soda into water

2. Wrap the silver price into aluminum foil

3. Put the wrapped silver piece into the solution and wait a few minutes

For a greater effect you might want to boil the water solution as chemical reactions occur faster at higher temperatures.

Why this simple technique works? Silver is usually tarnished as it forms silver sulfide. In order to remove sulfur from the silver, it is needed to put it into contact with a more active metal such as aluminum. The solution there provides with a path for sulfur to move from silver to aluminum.

How Anodizing Works

June 12, 2014Uncategorizedaluminum, anodeerimine, anodizing, corrosion, corrosion protection, electrochemistry, engineering, materials science, materjaliteadus, titaniumCaptain Corrosion

Anodizing is an electrochemical process where a thicker oxide layer is grown on the material. This is useful for improving an objects corrosion and wear resistance, manufacture nanoporous templates or give the material a decorative appearance. Not all materials can be anodized however as their oxides are not dense and hard but the technique has been widely used on aluminum, titanium, zinc, magnesium and their alloys.

The anodizing system consists of a power source, anodizing bath, electrolyte and anodizable material. The bath is usually made from a chemically resistant conductive material such as stainless steel and serves as a cathode. The anodizable material serves as an anode and is placed inside the anodizing bath with the electrolyte. Both the anode and the cathode need to be connected to the power source. The grown oxide layers properties depend on the material, used electrolyte, temperature and electrical parameters used for anodizing.

In order to produce a uniform oxide layer, the substrates are also treated before the process. The main problem is usually organic contamination of the surface, which prevents growth of the oxide layer. This is removed with organic solvents such as acetone. Often the thin native oxide layer is also removed via etching before the anodizing.