How can Bright Zinc plated Steel Shelves go rusty in a Fridge?

[Jimbob86]

Hi,

I have some Bright Zinc plated shelves which are currently being stored at 0-1'c. Over a period of 6 months they have become extremely rusty. How has this happened?

Please help...

 

[pallidin]

Good question, though I don't have an answer. I have seen the same type of shelves do this, with the zinc plating flaking-off.

My guess, is that there are different rates of expansion/contraction between the two metals, causing separation and cracks in the zinc plating, allowing moisture to enter and cause rusting.
But again, I don't know for sure.