Microwave plasma fluidized bed arc-PVD coating of particulate materials

A novel process for deposition of thin AlN and Al coatings on particulate carbon materials by means of an atmospheric pressure microwave plasma fluidized bed treatment is reported. The substrate powder and a fine aluminum powder are mixed and fluidized together in microwave plasma. Argon plasma yields a homogenous coating composed of pure aluminum on the substrate powder, whereas upon treatment in a reactive nitrogen plasma the deposited aluminum particles are nitrided and the resulting coating is an AlN ceramic. Coatings were characterized by means of SEM/FEM, EDX, XRD and TGA. Crystal structure of the deposited AlN was refined by Rietveld method.