Production of Al-TiB₂ composite alloy powder by a plasma arc CVD method

Abstract

Al-TiB₂ composite alloy powder was produced by a plasma arc CVD method using TiCl₄, BCl₃ and Al vapours. A plasma arc generated between a pair of Al or Al-Ti alloy electrodes was utilized both for the heating of reactants and for the vaporization of Al electrodes. The experimental results obtained are summarized as follows: (1) The reaction products were determined as Al-TiB₂ and Al-TiB₂-Al₃Ti composite alloys by X-ray diffraction method. (2) A plot of molar ratio of reactant vapour against TiB₂ content in the product showed a peak at molar ratio of TiCl₄ ranging from 0.6 to 0.63 in the mixture vapour of TiCl₄ and BCl₃. (3) Al-TiB₂-Al₃Ti composite alloy was formed when the molar ratio of TiCl₄ in CVD gas involving TiCl₄ and BCl₃ was larger than 0.5 and when Al-Ti alloys were used as electrodes. (4) The synthesized particles were considered to be consisted of the clusters of fine particles of Al-Ti alloy containing TiB₂ cores.