"PVD"

PVD is an acronym for physical vacuum deposition. These are coatings which are applied in a vacuum chamber without liquids being involved. The material which is to be deposited is heated and/or electrically charged such that it vaporizes into a gas. The parts to be coated may be electrically charged to attract the gas.

Vacuum coatings may range from the extremely thin, simple, and inexpensive aluminum coatings which gives shine to mylar party balloons, to quite exotic "hard coatings" like titanium nitride which is used as a very wear-resistant gold colored coating (the gold drills sold at hardware stores) and zirconium nitride (used to give 'lifetime' brass colored coating to plumbing fixtures and door hardware).