(48c) Cvd of Aluminum Compounds on Carbon Materials in Microwave Plasma Fbr

Deposition of coatings of aluminum, aluminum nitride and aluminum carbide on particulate carbon materials by means of an atmospheric pressure microwave plasma fluidized bed process is reported. Two types of short carbon fibers and a monocrystalline diamond powder were used as substrate. As source of aluminum trimethylaluminum was utilized with nitrogen and argon/hydrogen (5 vol% H2) serving as fluidizing and carrier gas. Microwaves at 2.45 GHz frequency were used for heating the substrate materials and for establishing a plasma in an in-house built monomode cavity. For deposition of coatings the substrate surface temperature was varied between 600ºC and 1100ºC. Because of their microwave transparency, diamonds were mixed with fibers and heated indirectly in the bed. Coatings were characterized by means of SEM/FEM, EDX, XRD, TGA and BET surface area. The influence of processing parameters on the decomposition conditions of TMA and on the chemical composition of the composite coatings is discussed.