Volume of zinc corrosion products

Hello all,

I have a quick question that all of you corrosion buffs could probably answer pretty easily.

What is the relative volume change between zinc and the corresponding products formed during corrosion?

Thanks alot for your time.

 

[bilge]

The answer to your question requires a little calculation --- and a litle thought.
First, for the calculation:

The relative volume change, delta-V, can be found by this:

delta-V = [(7.13/65.38)(molecular weight of the corrosion product/density of the corrosion product) - 1] X 100%.

Many of the corrosion products that can form on zinc are porous. Therefore you have to give some thought to the morphology of the particular corrsion product. The calculated delta-V, thus, is a minimum in the relative volume change.