aliesmal110-
What type of gears are you using?
What are the dimensions of the gear set?
What are the gear materials? Do you have the option of using alternate materials?
What are the tooth contact stress levels?
What are the lifecycle requirements?
Are there any cost constraints?
Unless you provide specific details about your problem, all we can do is provide speculative responses. For example, CoryPad's excellent suggestion for using liquid salt bath nitrocarburize (quench/polish/quench) will produce a hard (but relatively thin) nitride case on steel with good corrosion protection and resistance to scuffing under marginal lubrication conditions. However, this does not mean you can operate a pair of nitrocarburized steel gears at elevated load/speed without any form of lubrication and expect them to survive for long.
Looking forward to your post providing more details.
Regards,
Terry