An aluminum shield will do a lot more to deflect heat away from the alternator than spending a ridiculous amount of money on ceramic coating. I've seen underhood temps well over 200 degrees on a summer day, so the idea that heat is causing the alternator problems doesn't make good nonsense. Try using a remote BBQ thermometer under the hood and measure the temp while you're driving down the road with plenty of air flowing- - - -it should be a lot lower. The new remote I've started using while smoking pork butts will transmit up to 90 feet, and I'm already thinking up ways to make use of it for diagnosing automotive problems.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!