In this work, the ultrafine TiB₂ and ZrB₂ powders were prepared using TiO₂, ZrO₂, C, B₄C, and Ca as the raw materials. The process consisted of steps of carbothermic pre-reduction of oxide, boronization and decarburization reactions in Ca melt, wet leaching as well as deep deoxidation. The pre-deoxidation by carbothermic reduction successfully avoids the problem of evaporation loss of boron source in traditional borothermal reduction method to prepare borides due to the generation of boride oxide. Because of the strong exothermic behavior, the adiabatic temperatures in boronization-decarburization step as well as wet leaching step were calculated, and the results show that these reactions are mild and controllable. Furthermore, it was found that the high oxygen contents in as-prepared TiB₂ and ZrB₂ powders were resulted from the high temperature and low pH value during water leaching and acid leaching processes. After deep deoxidation at 1673 K in vacuum by mixture of C and B₄C, the particle sizes of the final TiB₂ and ZrB₂ powders were about 200 nm, and the oxygen contents were 1.26 wt% and 0.92 wt%, respectively.

本工作以TiO ₂、ZrO ₂、C、B ₄ C和Ca为原料制备了超细TiB ₂和ZrB _2粉末。该工艺包括氧化物的碳热预还原、Ca熔体中的硼化和脱碳反应、湿法浸出以及深度脱氧等步骤。碳热还原预脱氧成功地避免了传统硼热还原法制备硼化物时因生成氧化硼而导致硼源蒸发损失的问题。由于其强烈的放热行为，计算了渗硼-脱碳步骤以及湿浸步骤的绝热温度，结果表明这些反应是温和且可控的。此外，还发现所制备的TiB ₂和ZrB ₂粉末中的高氧含量是由于水浸和酸浸过程中的高温和低pH值造成的。_{采用C和B 4} C混合物在真空中1673 K深度脱氧后，最终TiB ₂和ZrB ₂粉末的粒径约为200 nm，氧含量分别为1.26 wt%和0.92 wt%。