I have etched a lot of blades, but I'm no expert. My method is in this thread.
Etching
I have read that doing the first neutralization with vinegar converts some chloride ions to a non corrosive form. (I'm no chemist) I then rinse and neutralize with ammonia, then with a slurry of sodium bicarbonate.
I've never had any corrosion or rusting issues doing it this way.
Good luck sir!