Coating of Small Particles by Chemical Vapor Deposition While the Particles are Fluidized

Coating of small particles is often employed to impart special properties to the particles. One process that has been used to accomplish this is chemical vapor deposition while the particles are fluidized. Because the depositing solids can plug small orifices, the gas distributors used for chemical vapor deposition in a fluidized bed of particles are different from those used for most other fluidized bed processes. The turbulent mixing of the gases by the particle bed and the high collection efficiency of depositing species by the large surface area of the particle bed can produce unique coating microstructures. Examples of these unique microstructures are those of isotropic pyrolytic carbon, fine-grained silicon carbide and carbon-silicon two-phase mixtures.