Most of the corrosion we see occurs on chrome plated wheels. Even high quality aluminum is very difficult to electroplate because aluminum is an extremely active metal that instantly forms an oxide skin, and you can’t plate oxides. Put metals like copper, nickel and chrome on it, develop a tiny perforation in the plating, add moisture, and you have a powerful corrosion battery where galvanic forces cause the aluminum to corrode. Eventually, the plating will detach from the wheel causing an escape path for the air, and you get a flat!
Fix-a-flat tire sealants are also very corrosive, and we recommend that you never use these products. If their use is unavoidable, at the first opportunity, have the tire dismounted and diagnose why you needed to use it in the first place. Repair that problem. Then completely clean and dry the inside of the tire and wheel prior to remounting. We have seen these products corrode chrome plated, powder coated, painted, and bare aluminum wheels.
Fortunately, most of the time we are able to restore full functionality to corroded wheels.