[Rhlsup]

I've been working on an optional science fair, based on the topic of oxidation rates of steel when you add different polymers/metal coatings to it.

Idea taken from http://www.corrosion-doctors.org/Training/HighSchool-rusting.htm

Of the two parts of the project, I did the second part, for which I got results near the same as the site. For those who understandably read through the link, I set up a chart with the oxidation tendences of different metals. From highest to lowest, this is how the list goes of the various metals, from what I got.

Magnesium>Zinc>Aluminium>Lead>Tin>Copper

Besides magnesium being the highest, these results make sense. As Zinc is quick to "sacrifice" itself, that makes galvanized steel very resistant to oxidation, etc., and why old copper pennies are so heavily rusted.

Now for the questions:

1. Why wouldn't magnesium be used to coat steel if it has a higher rate of oxidation? It is much more abundant as well, thus making even less sense.

2. As I don't really want to poison myself with cyanide, and would rather not trust internet retailers on buying materials for a chemistry project, I was curious as to why potassium ferri/ferrocyanide would be needed to find out oxidation rates.

3. Between the galvanized (zinc coated) steel sheet, and the polymer coated sheet, which SHOULD be less affected by oxidation?

4. Finally, assuming (correct me if I'm wrong), a blue'ish hue of phenalpthalein indicates a high rate of oxidation on the steel, while a reddish pink indicates a slow rate, and that the metals that are cut would have more oxidation, would steel sheets with high oxidation rates have the blue in the middle, with nothing on the side, and ones with low rates have pink on the sides, and nothing in the middle?



The last few questions are a bit difficult to answer without reading the experiment, which I didn't think I should have copy pasted here, but if anybody can respond, it would be greatly appreciated. I spent a good bit of time on this project, nearly finishing a 5 page research paper, and writing a whole notebook worth of research and  recordings of current results.

If anybody could help me out, it would be greatly appreciated.