Tef-Gel is good stuff. It is a PTFE based paste primarily used to prevent corrosion, galling, and seizing of hardware in corrosive environments and between dissimilar metals I use it on my sailboat anywhere that stainless comes into contact with aluminum as it prevents the galvanic corrosion that often occurs at those joints. I think it is better than grease on threaded joints. It is not a thread locker though so don't confuse it with Loctite blue or red. It is also not a grease for bearings.

On sailboats, there are a lot of places where stainless threaded fasteners are screwed into aluminum. I've removed fasteners that have been in place for 5 years or more, and find the Tef-Gel is still there and still in paste form even though you only use a very thin film on the threads.