The University of Manchester Inst of Science and Technology (UMIST) is a renowned school for corrosion in England. I'm sure there are others. Canada might be worth checking into as well because universities there are less costly and not as competitve as in the UK. Univ. of Toronto, Univ of British Columbia and U of Alberta all have pretty good corrosion-related degree courses.
In the US you might qualify for research or teaching assitantships to defray the cost. Good universities for corrosion include (in no special order) - Case Western University; Ohio State; Penn State; Univ. of Connecticut (Institute of Materials Science); MIT; Lehigh University;
An important consideration is the subject area you want to study - make sure that there is an obvious interest at the school in what you are interested in - for me biomaterials were important. This can vary a lot depending on the professors' interests. Some focus on high temperature corrosion, some on marine corrosion, some on exotic materials, etc.
The internet is a rich source for this type of information..
Good luck/veels geluk