Mechanochemical synthesis of Ti1−xZrxB2 and Ti1−xHfxB2 solid solutions

Solid solutions of TiB₂-ZrB₂ and TiB₂-HfB₂ were obtained under an inert atmosphere by high-energy ball-milling mixtures of Ti/Zr/B and Ti/Hf/B, respectively. Milling promoted mechanically induced self-sustaining reactions (MSR), and the ignition time was dependent on the initial composition of the mixture. The stoichiometry of Ti_1−xZr_xB₂ and Ti_1−xHf_xB₂ solid solutions was controlled by adjusting the atomic ratio of the reactants. The solid solutions were characterised by X-ray diffraction, transmission electron microscopy, electron diffraction, and energy dispersive X-ray spectroscopy. The results revealed that TiB₂-ZrB₂ possessed a nanometric microstructure and good chemical homogeneity. However, in the TiB₂-HfB₂ system, an inhomogeneous solid solution was obtained when a Ti-rich mixture was employed. The solid solutions showed good thermal stability; thus, can be used as raw materials for the development of technological materials for structural applications.