# What Affects The Rate Of Corrosion

Improved Essays
Most corrosion is an electrochemical reaction. Anything that affects the speed of the chemical reaction will in turn affect the amount of current flow, which will affect the rate of corrosion. The rate of corrosion is directly proportional to the amount of current in the electrochemical corrosion cell. If the current can be measured accurately, then an exact calculation of the metal loss can be made.

2.2.1 ELECTRICAL EFFECTS ON THE RATE OF CORROSION

Any issue that have an effect on the quantity of current flowing in a circuit can affect the speed of the electrochemical reaction (corrosion). Ohm’s law applies to those electrical circuits. The law states that the direct current flowing in a circuit is directly proportional to the potential
The electrolyte resistivity may be a property of the electrolyte. The definition of an electrolyte is a material that may permit ions to migrate, and also the resistivity of the electrolyte is the rate at which it permits ions to migrate at a given potential. Current is reciprocally proportional to resistivity (V/R=I) and thus, in an electrochemical cell. If the resistivity is doubled, and all different factors stay constant, the quantity of corrosion is cut in 0.5.
3) Contact Resistance
The contact resistance of the anode to electrolyte and of the cathode to electrolyte is a component of the overall corrosion cell resistivity—the lower the contact resistance, the greater the corrosion current. As the contact resistance increases, the corrosion cell current will decrease. The decrease will be in relation to the sum of the total resistance of the circuit. That is, the resistance of the electrolyte plus the contact resistance.
4) Coating of the Structure
Coating of the structure usually raises the contact resistance of the anode and therefore the cathode since most coatings have a high dielectric (non-conductive)
A more active metal is anodic to a more metallic element. Metal at an elevated temperature becomes anodic to identical metal at a lower temperature. Generally, as temperature will increase, corrosion increases. However, this relies on the availability of oxygen. Since elevated temperature makes a metal more active, it will become anodic for rest of the metal. So an electrochemical corrosion cell might cause fast corrosion on metals that are at elevated temperatures.
2) pH of the Electrolyte
The ph of the electrolyte in an electrochemical corrosion cell affects the speed of the corrosion by speeding up or slowing down the chemical reactions at the anode and/or the cathode. The ph of an electrolyte is basically the concentration of hydrogen ions. A ph. below 4 can increase the corrosion rate of mild steel. At a ph of 3 the corrosion rate can increase tremendously. Metals having the potential to react to an acid or a base, known as amphoteric metals, in addition show an increase in the corrosion rate in alkali environments. Aluminum and lead are some examples of amphoteric

## Related Documents

• Improved Essays

Melting and Boiling Points: The particles/substances which are present in a metal are held or joined together by strong metallic bonds. A lot of energy is used to separate these particles. That is why metals have high melting and boiling point. Metals are solid as well as crystalline.…

• 858 Words
• 4 Pages
Improved Essays
• Decent Essays

Alyssa Making Pennies Clean Pennies are shiny when their new, but after time they start to become dull. The one-cent coin was legal tender by the coinage act of 1864 (pennies.org). Abraham Lincoln is on the coin, and was put on the coin in 1909 (pennies.org). The penny was the first U.S. Cent to include the words “in God we trust” (pennies.org). Now how do they become dull and dingy?…

• 344 Words
• 2 Pages
Decent Essays
• Great Essays

Moreover, metallic bonds have a simple crystal lattice in solid state and are the weakest primary chemical bonds. Hence the reason to why pure metals are dissolved with other elements such as: carbon for mild steels. Metal alloys have increased strength and hardness. The structure of alloys reduces the space between each ion, so there is less space for delocalized electrons and it improves the chemical bond with each element within the…

• 1494 Words
• 6 Pages
Great Essays
• Improved Essays

In this lab we will be testing the water quality of the Lewis and Clark Lake. We will be testing to see if the water is good quality and good for the fish and creatures that need that water to live. The first step is to extract the water from the lake and analyze the way it looks. We should write down the description of the water. The second step is to take it to the lab to test the water for pollutants and to test the quality of the water.…

• 1435 Words
• 6 Pages
Improved Essays
• Improved Essays

Purpose: By doing this experiment, students will properly complete a redox titration well also determining the amount of hypochlorite ions present in the commercial bleach given. Introduction: Commercial Bleach and other commercial products like hair colouring agents, contain oxidizing agents. Oxidizing agents are substances that remove electrons from one or more reactants and thereby oxidizes it, whereas reducing agents are substance that give electrons to other reactant. There is some reaction that are called oxidation-reduction reaction, theses reactions are commonly seen in our day to day lives.…

• 1086 Words
• 5 Pages
Improved Essays
• Decent Essays

In most cases, a chemical reaction is able to occur in more than one way; enzyme kinetics studies the effect of how biological catalysts can influence biochemical reactions. Enzymes play an important role in regulating metabolic pathways in the human body and without enzymes they will not function efficiently. The rate of a reaction is enhanced by enzyme activity which provides alternate pathways for the reaction to proceed by.…

• 177 Words
• 1 Pages
Decent Essays
• Superior Essays

These anomalies were seen when 2 of the tests were supposed to react but did not, and another test where there was supposed to be no reaction but there was. The two main factors that could have affected the results would be galvanization and oxidation. According to study.com, oxidation is “At its most basic level, oxidation is the loss of electrons. It happens when an atom or compound loses one or more electrons. Some elements lose electrons more easily than others.…

• 2193 Words
• 9 Pages
Superior Essays
• Improved Essays

Acid, below-normal pH, causes many problems in our world today—from drinks to teeth, from pollution of industry to natural disasters. Acid is a chemical substance that can subdue alkalis, can dissolve specific metals and can turn them into salt, such as calcium, turns red on blue litmus paper, is corrosive or sour-tasting when it comes to liquid, generates pain in wounds, and turns colorless when placed in phenolphthalein which is used as a basic to acid indicator ("Definition of acid in English:"). Alkalis is any kind of substance that can produce OH ions, hydroxide ions, in water, which can also be known as 'basic', or 'basicity' ("GCSE CHEMISTRY - What is an Alkali? - What is a Base? - GCSE SCIENCE."). Litmus is a weakly acidic, organic…

• 1089 Words
• 5 Pages
Improved Essays
• Improved Essays

1. The pH of Welch’s Juice Significantly different than what I had hypothesized. I reject that part of my hypothesis because I feel like it was too far from what the actual number was. I had hypothesized 6 because I felt like the other parts of that solution would make it less acidic. I was wrong and the actual number was 3.…

• 281 Words
• 2 Pages
Improved Essays
• Improved Essays

Problem Statement: How do different amounts of soil affect the pH of water? Is the relationship the same for different types of soils? Background: PH is a measurement of how many ions of hydrogen are found in a solution. The pH scale measures how alkaline or acidic an object is.…

• 659 Words
• 3 Pages
Improved Essays
• Decent Essays

Salt use on roads in winter salt is a common way to clear slippery roads. Salt lowers the temperature of the water which causes it to melt and it's one of the effective way of lower weather related collision. Using salt on road lower car accidents on highway up to 80%. However, salt used on roads causes rust on cars and environmental studies had showed that salt use for de-icing could affect water supplies, soil,and wildlife. Negative effect of using road salt…

• 311 Words
• 2 Pages
Decent Essays
• Decent Essays

Widely used all over the world, wrought iron fencing and railings can last for decades. Even with the best craftsmanship, iron is not immune to rust. A result of the natural reaction between iron and oxygen when moisture is present, rust will eventually overtake an entire iron structure until nothing else is left unless adequate prevention measures are taken. Here to explain how to protect your wrought iron gates and fences this winter is Elsmere Ironworks, Cincinnati, OH's leading iron fabricators. Galvanization: For corrosion protection that lasts a lifetime, ask Elsmere Ironworks about hot-dip galvanization for your outdoor fencing and railings.…

• 283 Words
• 2 Pages
Decent Essays
• Improved Essays

In the cell Zn (s) + Cu2+(aq) ↔ Zn2+ + Cu(s), as the concentration Cu2+ was increased from 0.10 M to 1.00 M, this caused the reaction to shift right and thereby increasing the cell potential of cell 2 from 1.10 to 1.13 Volts. Electrical potential depends upon the concentrations of the substances, the temperature, and the pressure, as these stated factors increase beyond standard values, so does electrical potential of the…

• 1122 Words
• 5 Pages
Improved Essays
• Improved Essays

The “Acid Bath Murderer” case was about a man named John George Haigh. It was said that he killed his boss and dumped him into a forty-gallon barrel of acid (Casale,2017). Like most known killers, Haigh blended well into society. Born into a strictly religious family on July 24, 1909, Haigh claimed his childhood to be strict and somewhat lonely. During his youth, Haigh had an accident which resulted in having a blue bruise on his head.…

• 1159 Words
• 5 Pages
Improved Essays