Chemical vapor deposition coatings in fluidized bed reactors

Summary A coating technique based on chemical vapor deposition (CVD) in a fluidized bed reactor (FBR) is described. To coat an article, we load the coating material as a powder in an FBR and fluidize it using an inert gas. The system is heated to operating temperature, and vapors of HBr are mixed with the fluidizing gas. The sample to be coated is suspended on top of the bed or immersed into the bed. The reaction of the HBr with the powder in the bed produces halide species of the coating material that can deposit a coating on the substrate by a disproportionation or reduction reaction. Using this technique, we deposited titanium, silicon, zinc, TiN and Si 3 N 4 coatings on substrates such as copper, steel, silica and graphite.