Powder coating is the process of applying a dry powdered paint compound made of pigments, specialized resins and fillers that melt and fuse together during the curing process to form a painted finish. The solid powder particles are electrostaticaly charged when exiting the low-velocity air powered spray gun.
Typically any metal object that can hold the electrostatic charge needed to affix the sprayed powder and can tolerate the high heat levels of the curing process. Mild steel, galvanized and electroplated steel, aluminum, stainless steel and most other steel alloys can be powder coated.