Gosh, that sounds dangerous.  Do you really mean she is trying to bite the iron while it's hot?  And laying her head on the ironing board near the hot iron? 
Yep!  Yep!   BUT when I put the iron down,,,I don't put it on the board,,but rather on my sink that is back far enough that she can not reach it. She only lays her head on the board after she has been scolded...kind of feeling bad look.  
She doesn't just bite the iron,,,as you can see in the pictures,, ,she stares it down for a long time...then once in a while she tries to bite it.  It might be the noise,, it might be the reflection...and is probably BOTH.