MECHANOCHEMICAL SYNTHESIS OF Ni/HfC COMPOSITE STRUCTURES

The structural-phase evolution of the mechanochemical formation of Ni/HfC mechanocomposites containing 50 and 70 wt.% nickel was studied using X-ray diffraction analysis, scanning electron microscopy, and energy dispersive spectroscopy. It has been shown by X-ray diffraction analysis, that during mechanochemical synthesis in a ternary mixture of elemental powders Ni, Hf and C at a stoichiometric ratio of Hf and C, the formation of hafnium carbide occurred already after 40 s. For both compositions, the crystallite sizes of the nickel rapidly decrease upon mechanical activation for up to 4 min compared to the initial. Intensive formation of hafnium carbide is recorded during mechanical activation with duration of 4-8 minutes. With mechanical activation for 12 and 20 min, the processes of secondary structure formation lead to homogenization of the product and depletion of hafnium carbide in carbon to the composition HfС.