Controlled synthesis of different morphologies of TiB2 microcrystals by aluminum melt reaction method

TiB2 microcrystals with different morphologies, including hexagonal plate-like, tower-like and dendritic, were fabricated by aluminum melt reaction method in this study. The growth mechanisms of these microcrystals are also discussed based on the fundamental crystal growth theories. It is found that the growth of TiB2 is controlled by two-dimensional nucleation in aluminum melt. If the atomic concentration, reaction rate and atomic diffusion rate in the melt are high, TiB2 microcrystals exhibit hierarchical tower-like and dendritic morphologies. Otherwise, the single crystal of hexagonal plate-like morphology is obtained. The growth of the hierarchical TiB2 microcrystals is controlled by two steps, intermittent two-dimensional nucleation and continuous lateral spreading of layers on the growth faces.