This is the sort of wear that happens when EP (extreme pressure ) lubricants are used with bronze worm gears, the lube corrodes the surface and the worm wears off the corrosion in a continuous process; EP lubes should NEVER be used with bronze worm gears; of course, I do not know that is what happened in this case, but it is familiar look/ failure. If only someone spoke Portuguese, we could ask ---
I dont know for sure but i do know of bearings made called "phosphor bronze" so im gonna make an educated guess at sulfur being the answer to your question!I forgot- is it the phosphorous that kills bronze? or sulfur? Senior moment