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Zirconium-boron reactive composite powders prepared by arrested reactive milling
Journal of Energetic Materials ( IF 2.1 ) Pub Date : 2019-10-23 , DOI: 10.1080/07370652.2019.1679279
Daniel Hastings 1 , Mirko Schoenitz 1 , Edward L. Dreizin 1, 2
Affiliation  

ABSTRACT Zirconium-boron composite powders with the stoichiometric bulk composition corresponding to ZrB2 were prepared using high-energy milling in a shaker mill starting with elemental boron and zirconium. Milling times up to 3 hours were explored. The characterization of the prepared powders included measuring their particle size distribution, crystal structure, and assessment of particle structure and morphology. Reactions in the prepared powders were characterized using thermal analysis as well as custom ignition and combustion experiments. Composite powders consist of a Zr matrix with B inclusions mostly 100 nm or less in size. The homogeneity of mixing between boron and zirconium improves when the milling time increases from 1 to 2 hours; it is not affected by longer milling times. Boron and zirconium start reacting during milling; the degree of this reaction becomes appreciable when the milling time reaches 2 hours. In air, ignition of both pure zirconium and the prepared powders occurs in the same temperature range of ca. 400–700°C for the heating rates varied from 2000 to 20,000 °C/s. In fuel-rich conditions, ignition of the prepared powders is affected by the reaction between B and Zr, which occurs less readily for powders milled for 2 hours or longer. In air, particles of the prepared composite powders burn faster than either pure boron or zirconium. Flame temperatures for individual composite particles burning in air are reasonably close to those predicted as adiabatic flame temperatures for this composite-air system at stoichiometric and fuel-rich conditions. In combustion products of an air-acetylene flame, the burn rates of the prepared composites are lower than that of zirconium and are comparable to that of boron. Powders prepared by 1-hour milling burn faster than powders prepared using longer milling times.

中文翻译:

阻滞反应球磨制备锆硼反应复合粉体

摘要 锆硼复合粉末具有对应于 ZrB2 的化学计量整体组成,在振动磨中使用高能研磨制备,以元素硼和锆为起始原料。研究了长达 3 小时的研磨时间。制备的粉末的表征包括测量它们的粒度分布、晶体结构以及对颗粒结构和形态的评估。使用热分析以及定制的点火和燃烧实验来表征所制备粉末中的反应。复合粉末由 Zr 基体和 B 夹杂物组成,其尺寸大多为 100 nm 或更小。当球磨时间从1小时增加到2小时时,硼和锆之间的混合均匀性提高;它不受较长研磨时间的影响。硼和锆在研磨过程中开始反应;当研磨时间达到 2 小时时,该反应的程度变得明显。在空气中,纯锆和制备的粉末在大约相同的温度范围内点燃。400-700°C 的加热速率从 2000 到 20,000°C/s 不等。在富含燃料的条件下,制备的粉末的点燃受 B 和 Zr 之间的反应的影响,对于研磨 2 小时或更长时间的粉末,这种反应不太容易发生。在空气中,制备的复合粉末颗粒比纯硼或锆燃烧得更快。在空气中燃烧的单个复合颗粒的火焰温度与在化学计量和富燃料条件下该复合空气系统预测的绝热火焰温度相当接近。在空气-乙炔火焰的燃烧产物中,制备的复合材料的燃烧速率低于锆,与硼相当。通过 1 小时研磨制备的粉末比使用较长研磨时间制备的粉末燃烧得更快。
更新日期:2019-10-23
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