[Francbb]

Hello,

I am taking this pre-major engineering course at my college, and as part of it we have to prove that this engine we made on Solidworks can withstand corrosion. Specifically, we made it so we established a test criterion where the engine has to last 25 years before the corrosion ruins it. It is also made out of 1060 aluminum alloy.

I read about an experiment (https://iopscience.iop.org/article/10.1088/1757-899X/872/1/012058/pdf) where they dipped 1060 aluminum alloy rods that were 10mm(length) by 12 mm(diameter) (the dimensions suggest that they are not a rod but whatever) in 200mL H2SO4 and HCL of various concentrations for various time periods and measure the weight loss of the rod. This equation was used: R=87.6W/(DAT). where W is the weight loss in grams, D is the density in g/cm^2 (might be a typo since it's supposed to be g/cm^3), A is the area in cm^2, and T is the time in hours. We used the weight loss rate value when it was dipped in in 2M HCl after 480 hours as the data point, which was .02515. What I find confusing is that their "typo" produces 1/hour as the unit for R, which makes sense, whereas without the typo the unit is 1/(cm*hour), leading me to believe that the 87.6 constant value in the equation accounts for it.

My main question, however, is how can I translate that rate to the rate of corrosion in oxygen? I cannot seem to find anything that is helpful online, and it is way out of my scope as I am a comp sci student who took ap chem 3 years ago.

Thank you!

[Orcio_87]

how can I translate that rate to the rate of corrosion in oxygen?

Experiment is based on the loss of weight of aluminium rod, while oxygen corrosion will led to increase of its weight.

To calculate rate of corrosion in oxygen you will need to use equation:

Al + 3/2 O₂ ---> 1/2 Al₂O₃

This means that every 48 g increase in weight is loss of 26,98 g aluminium.

But - from that what I know, Al does not react with oxygen in that way if is not processed into powder.