Everybody wants to stay away from aluminum sprockets. Why I do not understand. You should be replacing the sprockets, front and rear everytime you replace the chain. The aluminum sprockets I have used have easily lasted the life of one chain. I put my third chain on the bike (2nd replacement) at 35k including sprockets and a T'bird cush drive. That should have probably been replaced a little earlier but what can I say, I was riding it.
