Ron

[|**Which Metal Is the Most Resistant to Corrosion?**] h Objective The purpose of this project is to determine which metal would be the most corrosion-resistant. Introduction Corrosion is what happens to metals when they are exposed to water and oxygen in the environment. When iron or steel corrodes, the iron forms reddish brown colored oxides and hyrdoxides: what we commonly refer to as "rust." Rusting of iron is an electrochemical process. The iron atoms lose electrons (the chemical process of oxidation), which break down water into oxygen and hydroxide ions (the chemical process of reduction). The hydroxide ions react with the oxidized iron and the dissolved oxygen in the water to form iron oxide. Iron oxide is permeable to water and oxygen, so the chemical reaction can continue beneath the surface layer. For other metals, such as copper and alumnium, an oxidized layer on the surface actually protects the metal underneath from further corrosion. In this project, you will measure the corrosion rate of different metals when exposed to fresh and salt water. Terms, Concepts and Questions to Start Background Research To do this project, you should do research that enables you to understand the following terms and concepts:
 * rust,
 * corrosion,
 * copper,
 * iron,
 * steel,
 * stainless steel,
 * aluminum,
 * zinc.

More advanced students should also study:
 * electrochemistry,
 * oxidation,
 * reduction.

Questions
 * Why are roofing nails zinc-coated?
 * What chemical reaction occurs when iron rusts?

Bibliography
 * Wikipedia contributors, 2006. "Rust," Wikipedia, The Free Encyclopedia [accessed October 24, 2006] [].
 * NJScuba.net, 2006. "Artifacts & Shipwrecks: Iron, Steel & Rust," New Jersey Scuba Diver [accessed October 24, 2006] [].
 * Asato, R., date unknown. "Corrosion," Internet Chemistry, Leeward Community College [accessed October 24, 2006] [].
 * US EPA, 2006. "Copper: Corrosion Research," United States Environmental Protection Agency [accessed October 24, 2006] [].
 * Corrosion Doctors, date unknown. "Aluminum Corrosion," Corrosion-Doctors.org [accessed October 24, 2006] [].

Materials and Equipment To do this experiment you will need the following materials and equipment:
 * short lengths (about 10 cm) of solid wire,
 * made of a different metals, e.g.:
 * steel or iron,
 * zinc-coated steel,
 * copper,
 * aluminum.
 * you should be able to find these at your local hardware store,
 * you will need 3 lengths of each type of wire,
 * match wire diameter as closely as you can;
 * 2 pencils,
 * 2 jars,
 * water,
 * salt,
 * lab notebook,
 * graph paper and colored pencils,
 * camera (optional).

Experimental Procedure
 * 1) Do your background research so that you are knowledgeable about the terms, concepts, and questions, above.
 * 2) Cut three 10 cm lengths of each type of wire.
 * 3) 1 length of each type of wire will be immersed in plain tap water,
 * 4) 1 length of each type of wire will be immersed in salt water,
 * 5) 1 length of each type of wire will remain dry in air.
 * 6) Fill one jar 2/3 full of plain tap water.
 * 7) Fill the other jar 2/3 of salt water.
 * 8) Take one sample of each type of wire and wrap the end of the wire (2–3 turns) around a pencil. Leave some space between the wires, but make sure that they will fit into the jar. Repeat for a second set of wires on the second pencil.
 * 9) Immerse one set of wires in plain tap water, and the other set in the salt water. The pencil should rest across the top of the jar.
 * 10) Observe the wires at least once a day for two weeks. Take notes of your observations in your lab notebook. Examine the entire length of each wire. Are the changes you notice the same along the whole length? Why or why not?
 * 11) If you have a camera, take photographs of the wires at the start of the experiment and whenever you notice an interesting change. Use your camera's date function (if it has one) to mark the picture; otherwise, be sure to keep good notes about when you took the pictures in your lab notebook.
 * 12) At the end of the experiment, compare the 3 sets of wire samples:
 * 13) the set kept in plain tap water,
 * 14) the set kept in salt water,
 * 15) the set kept in air.
 * 16) Develop a graded rating scale (1–5 or 1–10) to describe the changes you observed. Each number in your scale should have clear rules for distinguishing it from the other numbers.
 * 17) If you took pictures, use your photographs to illustrate your rating scale on your display board.
 * 18) Use your rating scale to make graphs that show what happened to the different metals in each of the three conditions.
 * 19) Which combination (of metal and environmental conditions) showed the greatest amount of oxidation?
 * 20) Which combination (of metal and environmental conditions) showed the least amount of oxidation?

Variations
 * In addition to your visual observations, you could also measure the weight of the wires at the beginning and end of the experiment. Do you think the weight of any of the wires will change? Why or why not? What actually happens?
 * How does temperature affect the oxidation rate of different metals? Design an experiment to find out.
 * You could try different concentrations of salt water. Does more salt in the water speed up the oxidation reaction? Why or why not?
 * What happens if there is very little oxygen in the water? Use boiled water (to remove oxygen), and fill the jar all the way to the top with water (pour carefully so that you don't re-oxygenate the water). Attach the wires to the bottom of the jar lid (e.g., with hot glue), and close the jar lid tightly. Compare to a similar jar set-up with water that wasn't boiled.
 * What happens if the pH of the water is changed? You could make the water acidic by adding vinegar, or basic by adding baking soda.
 * Have you seen pictures of the //Titanic// or other underwater shipwrecks? What happens to artifacts like iron cannonballs when they are brought to the surface from a shipwreck? Design an experiment to see what happens to metal wires immersed in fresh or salt water and then exposed to air.
 * Compare painted and unpainted wires.

Credits Andrew Olson, Ph.D., Science Buddies Sources http://www.corrosion-doctors.org/MatSelect/corrcopper.htm
 * For more science project ideas in this area of science, see [|Materials Science Project Ideas].

Ronald Yeager Science Fair Background research on Corrosion Corrosion takes on many forms. The most common forms of corrosion, as applied to HVAC equipment, are known as galvanic and general corrosion. Each of these corrosion types can lead to equipment failure. As a result, special attention will be given to each of these types of corrosion. Bi-Metallic Construction The standard condenser coil is manufactured from copper tubes mechanically bonded to aluminum fins. This bond crates a classic bi-metallic couple necessary for galvanic corrosion. An electrolyte in the presence of the copper-tube and aluminum-fin couple is sufficient to initiate a corrosion reaction. The most common sources of chloride contamination are marine and coastal environments. The most common sources of chloride contamination are marine and coastal environments. Sea spray, mist, and fog contain tiny droplets of salt water which can be transported several miles by ocean breezes and tidal currents. It is not uncommon to experience salt water contamination up to five miles from the coast. As a result, protection from ocean-borne electrolytes in inland areas is recommended. Since general corrosion consumes metal and forms metal oxides, unsightly surface conditions result. Surface tarnish on copper, such as black, green, brown, or yellow deposits, lead to the perception of poor quality. Copper-fin coils experience similar attack of the copper metal. Failure of a contaminated copper-fin coil can result from fin degradation and ultimately lead to loss of tube integrity. A clean copper tube in an uncontaminated atmosphere maintains system integrity. However, in a contaminated atmosphere, metal oxides begin to form on the copper tube. Prolonged exposure to a contaminated atmosphere usually results in tube failure. Corrosion is the number 1 enemy of metals. Since the metal age, metal such as iron is subjected to rust and corrosion.
 * Galvanic corrosion** is when dissimilar metals are electrically connected in the presence of an electrolyte, a reaction occurs. This reaction is known as galvanic corrosion. There must be a bi-metallic couple between two dissimilar metals in the presence of an electrolyte solution. Without these ingredients, galvanic corrosion will not occur. Galvanic corrosion most often causes fin degradation, which may ultimately lead to the destruction of the coil. Galvanic corrosion of the unprotected coil begins at the bi-metallic couple between the copper tube and aluminum fin. As corrosion begins within the copper-to-aluminum bond in the standard coil construction, the aluminum bond in the standard coil construction, the aluminum fin deteriorates. Consumption of the fin continues until coil performance is affected and severe visual deterioration results.
 * General Corrosion** is the degradation of metal caused by a reaction with the environment, such as oxidation and chemical attack of the metallic surface. Copper is susceptible to attack from sulfur-containing gases. The result is the formation of a nonproductive layer on the material surface. Unprotected metal will continue to react with the contaminant and corrode. Under severe, prolonged conditions, the metal continues to corrode until the integrity of the equipment is jeopardized. Unprotected copper in polluted industrial environments can lead to failure of the refrigeration system. Sulfur- and nitrogen-based electrolytes are often the cause of accelerated corrosion in industrial environments.

Man has since seek ways to prevent corrosion from taking place, by isolation, by electroplating, by coating with anti-rust paints, by induced electrical current, aka ICCP (Impressed Current Cathodic Protection.) and sacrificial anodes.

To understand corrosion is to know Chemistry and Physics. Abrasive wear and tear, tensile strength of metals and forces of stress both physical and chemical reactions. A study of Vibrations and resonance of a metal must be applied to the buildings of bridges and structures of steel and metals. In the past, bridges collapsed due to the resonant vibrations which cause it to snap and be broken. Studies on the cause of the destruction point to resonant vibration of the bridge cause by wind velocity. One good example is the TACOMA BRIDGE collapse.