Weathering In A California Climate? Essay, Research Paper
Does treating metal reduce the effects of weathering in a California climate? This experiment deals with the elements of weather against metal; wind, rain, solar radiation, oxidation (uniting a substance with oxygen), and heat (the presence and absence of). My hypothesis is that the painted protected metal will fare better than the bare metal during the weathering. The reason I believe this will happen is that the protected metal has that extra layer, so it will be harder for the bombardment of changes to hurt the metal.
The protectants for metals include various types of touch-up paints, polishes and waxes, body fillers, washes, and various other types of chemicals. Metal protection is most present in the automotive appearance industry. Of the three major segments of the market, color waxes lead with 36% of sales; protectants follow with 27%, and touch-up paints account for just over 26%. Chain retailers carry an average of 1.5 lines of touch-up paints and 5.5 lines of waxes/polishes. The average number of protectants in aftermarket outlets is three. According to a market research survey, 69.9 million people, or 37% of American adults, use car wax or polish. (http://www.findsvp.com/tocs/ML0165.htm)
The reaction of oxygen with a metal results in the formation of a metal oxide scale which in most cases protects the underlying metal against further corrosion. Contamination of the air, e.g. with carbon dioxide, sulfur dioxide and water, accelerates the oxidation rate considerably. The temperature at which the oxidation scale is formed depends on the chemical composition of the metal alloy.
Alseal 518 is a coating composition formulated for protecting ferrous alloys from both high temperature heat oxidation and at the same time offer sacrificial (cathodic) protection to the base metal. Because of its high temperature capabilities, it offers protection when exposed to cyclic high temperature and corrosive salt environments (like a California climate); it provides thermal stability. Tests have been conducted using low carbon steel alloys. There was no loss of weight after several weeks continuous exposure at 1000.F. After exposure to 5% salt spray for 1000 hours, there was no evidence of corrosion. The coated metal will not crack, spall, or fail after shocking from 1100.F to room temperature repeatedly. (http://www1.che.ufl.edu/meeting/1997/annual/session/81/a/index.html)
For an oxide to be protective the oxide-metal volume ratio must be somewhat larger than the unity, the oxide must keep good integrity and must remain adherent to the substrate. Chromium as well as nickel, silicon, and aluminum are used as alloying elements to improve the oxidation resistance in alloys.(http://www.metalogic.be/MatWeb/reading/gas/ka_ht/hto2mat.htm)
Materials
a long piece of metal; a car door (4 x4 )
a can of wax
a sander
Procedure
1. The metal will be divided into three sections.
2. The 1st section will be stripped down to the bare metal.
3. The 2nd section will just have paint.
4. The 3rd section will be covered in one layer of wax.
5. The metal will be exposed to the weather.
6. I will periodically examine it for damage or erosion.