if thats your idea of corroded armour, you chose the wrong god
id go for a few more washes or even just paint the armour rusted and
then drybrush it with metal.
you can do this with:
- thick base of scorched brown. the bumpier the better.
- build up by adding some bestial brown up to 1:1
- add some blazing orange to this 1:1:1, remember keep this really thick so its builds up texture making it look like really rusted metal
- [ick out the edges with boltgun metal - this shows where the rust has rubbed off and exposed the actual metal
- follow up with a chestnut ink
again, taht might be more than youre looking for but, its an option