Magnesiothermic production of metal borides by VCS or SHS was investigated by several scientists. Studies were generally focused on the production of TiB2. Sundaram et al. [24] investigated the reaction chemistry of TiB2 formation through TiO2–Mg–B2O3 system. Formation of side products such as Mg3B2O6 was observed in this study in addition to the expected phases, TiB2 and MgO. Bilgi et al. [25] also reported the formation of Mg3B2O6 during magnesiothermic production of TiB2 from TiO2–Mg–B2O3 mixtures. Reaction chemistry of ZrO2–Mg–H3BO3 system was studied by Khanra et al. [15]. According to this study, formation of Mg3B2O6 was expected, however; it was not detected in XRD patterns. Absence of Mg3B2O6 was explained by the possibility of its subsequent dissociation. Another important outcome of their study was the incomplete conversion of ZrO2 to ZrB2 despite using excess amount of Mg. Incomplete conversion was attributed to the stability of ZrO2. In a study about the mechanochemical formation of ZrB2, Setoudeh et al. [17] produced ZrB2 by MCP via magnesiothermic reduction after 15 h of milling in a tumbling mill. As in VCS, incomplete conversion of ZrO2 was observed in MCP, however; formation of side products such as Mg3B2O6 did not take place.