Corrosion
Corrosion is the destruction or degradation of metals due to a redox reaction between a metal and various substances in the environment that produce undesirable compounds. In ordinary language, corrosion is called kararatan. The most common example of corrosion is iron fi gure.
Corrosion is an electrochemical process. In iron corrosion, certain parts of the iron act as anode, in which iron undergoes oxidation.
Fe (s) <-> Fe2 + (aq) + 2e
The freed electrons in the anode flow to another part of the iron acting as a cathode, in which the oxygen is reduced.
O2 (g) + 4H + (aq) + 4e <-> 2H2O (l)
or
O2 (g) + 2H2O (l) + 4e <-> 4OH- (aq)
The iron ions (II) formed at the anode subsequently oxidized to form iron (III) ions which then form the hydrated oxide compound, which is iron rust. As to which part of the iron acts as anode and which part acts as a cathode, it depends on various factors, such as impurities, or the density of the metal.
Corrosion can also be interpreted as an attack that damages the metal because the metal reacts chemically or electrochemically with the environment. There is another definition that corrosion is the opposite of a metal extraction process of its mineral ore. For example, iron ore minerals in the wild are present in the form of iron oxide or iron sulphide compounds, after extracting and treating, an iron will be produced for the manufacture of steel or alloy steel. During use, the steel will react with the environment causing corrosion (back to the iron oxide compound).
Volta series and Nernst's law will help to know the possibility of corrosion. The speed of corrosion is highly dependent on many factors, such as the presence or absence of the oxide layer, since the oxide layer can block the potential difference against the other electrode which will be very different when it is still clean from the oxide
Iron corrosion prevention techniques
- Painting
- Wrapped in plastic
- Coating with chrome (Cromium plating)
- Coating with tin (Tin plating)
- Zinc coating (Galvanization)
- Anode sacrifice (Sacrificial Anode)
We know, corrosion can give negative effects in everyday life. Are there any positive effects we can encounter? Then what are the effective ways to prevent corrosion?
BalasHapusIn my opinion there is no positive impact of corrosion,
HapusUsually to keep us with a layer of paint
How to eliminate corrosion?
BalasHapusSoak in vinegar, Use lemon or lime, Use phosphate or hydrochloric acid, Use potatoes, Acidic materials, soda
HapusCan if the iron that has been corrosion changed to be what the original reaction?
BalasHapusIf to remove the corrosion would be and for the reaction would not exist anymore because the corrosion is gone
HapusHow to overcome corrosion with anode sacrifice (Sacrificial Anode)?
BalasHapusThe iron coated or in contact with another more active metal will form the electrochemical cell with iron as the cathode. Here, iron serves only as a site for the reduction of oxygen. Other metals act as anodes, and undergo oxidation reactions. In this case iron, as a cathode, is protected by other metals (as anodes, sacrificed). Iron will be safely protected as long as the protective metal is present / not yet exhausted.
Hapuswhy painting can prevent iron corrosion?
BalasHapusBecause Cat avoids contact with air and water. Paints that contain lead and zinc (zinc) will be better, because both protect the iron against corrosion.
HapusHow do we know the presence or absence of oxide layers?
BalasHapusThe cathode content already exists on the metal itself, but different metal then the difference also its content
Hapus
BalasHapusI've heard of corrosion on oil pipes. Can you explain why it happened?
@hudiaumamifaisal
Biological corrosion in pipes is generally caused by microbes. Microbial corrosion in the process is considered a separate cause, which in itself can be or is a combination of a number of different microbes. Microorganisms present in aerobic conditions, as well as anaerobes. Anaerobic conditions are always present in a microenvironment, under aerobic conditions. The condition of pH and the availability of nutrients is also a factor determining whether a type of microorganism can develop in the soil and cause corrosion.
HapusWhat causes Zinc coating (Galvanization) can be one of the handling of corrosion?
BalasHapusZinc can protect the iron even if the lining is damaged. This is because the iron electrode potential is more negative than zinc, so the iron in contact with the zinc will form an electrochemical cell with iron as a cathode. So the zinc will experience oxidation, while the iron will be protected.
HapusWhat is meant by electrochemical process ?
BalasHapusThe electrochemical process is a redox (oxidation-reduction) reaction in which the energy released by the spontaneous reaction is converted to electricity or where electrical energy is used to prevent non-consumptive reactions
Hapus