If you are willing to buy them, the IHS website may be able to find them. It has a good keyword search. Even if you don't plan to buy it, you might be able to find the spec number and then Google for a free downnload. I don't know if you need an account to search though. If you Google for MIL-specs, you should be able to find the government database too. There is one I found a couple of years ago that was the gov't site that could find ANY spec in the whole gov't - EPA, OSHA, the whole works. The thing is I only use IHS. IHS will also find AMS and ASTM and other industry standards by searching on the keword corrosion.
Update:
I went and looked at the IHS website. You can search without an account. It did not find MIL-Specs with a keyword search on corrosion. My corporate account will search specifically for MIL specs.
The general search tab did find what seems to be a good source though if you are willing to ante up $196.
http://store.ihs.com/specsstore/controller?event=SEARCH_RESULTSIf you can wait until Monday, I can post up the search from my IHS account if you have not already found a MIL-Spec.