I have a set of Chrome Aluminum rims, and two of them have scratches on them. So instead of buying new ones, is it possible to paint them. I was thinking black.
If the rims are still in good shape (no corrosion, bad scuff marks from curbs, etc) then yes, it's cost effective to powder coat them. I wouldn't get the chrome plated as you mentioned in the title as it's a lengthy process and it'll add more weight to the wheels than if you were to powder coat, as powder coating is done to the whole wheel where as chrome plated only goes on the outside (not inner areas) of the wheel so it'll need to be rebalanced.
You have either chrome or aluminum, not the same, 2 different rims. You cannot paint either, paint eill not stick to chrome or aluminum, it will just flake off.
Chrome rims and aluminum rims are not the same thing. There are chrome plated aluminum rims, but not many. Aluminum rims can be painted pretty easily as aluminum is pretty soft and you can sand it easily to paint it. If they are chrome plated it is harder to do because chrome plating is very hard, and doesn't sand easily, making it hard to get something to stick. Go to an auto paint store and tell them what you want to do. Use the best materials you can get, otherwise the paint will peel off and it will look worse than it does now.