Mechanochemical synthesis of TiN/TiB2 and TiN/TiSi2 nanocomposite powders via high energy ball milling

Abstract

TiN/TiB2 and TiN/TiSi2 nanocomposite powders have been mechanochemically synthesized from Ti/BN and Ti/Si3N4 powder mixtures, respectively, employing high-energy ball milling. These composite powders are formed by displacement reactions between titanium and nitrides during milling. These reactions exhibit a self-propagating character. The as-milled powders have been characterized using X-ray diffraction and transmission electron microscopy. After the reactions, the crystallite sizes of both powders decrease continuously during milling down to about 10 nm. The annealing of the as-milled TiN/TiSi2 powders leads to crystallite coarsening and appearance of C49 TiSi2. It is found that the structure of TiSi2 changes from C49 to C54 between 900 and 1000 degreesC.