Is there different types/quality of zinc nuts? are they zinc plated steel? any recommendations/specifications one would look for if you've completely gnarled up your OEM nuts? I know that all nuts are not made equally.
I have sort of learnt something today, thanks for adding that background info, I do add a tad of lithium grease.
I would assume Galling is something you would notice if it happens even after googling the word I am still not overly clear on what it, could you provide an example or an idea of the signs to look out for.
Aluminium, stainless steel and titatium stay shiny necause their surface oxidises in air. The very thin oxide layer that forms more or less instantly protects the rest of the metal from corrosion. Galling is what happens between the threads of the nut and the bolt. The friction and pressure on the threads when you tighten the nut rubs off the oxide layer leaving clean metal to metal contact, which makes it stick. When you continue to tighten,metal is pulled off the surface, which weakens it a bit. The end result is that the threads can weld themselves together when you've finally tightened the thread. That not only makes it very difficult to undo, but it can twist the bolt or whatever the nut is fixed to or damage the thread when it finally lets go. Galling is more of a problem when you use those three metals in any combination or the same for a nut and bolt.
Zinc plating or zinc galvanising (dipping in zinc) is just a way of protecting steel against corrosion. There are different grades of steel, which are what affect the strength. Generally, all zinc coated steel nuts should be more than adequate for an ebike motor, providing that you use the correct spanner and don't over-torque or cross-thread them. Also, axles are very hard steel. if you have a defect on the thread, it will cut into and damage the nut, so if ever a nut doesn't spin on freely, you should check why, not just apply more force.