Dynamic Compaction of Combustion‐Synthesized Hafnium Carbide

Abstract

The explosive-consolidation technique developed to fabricate combustion-synthesized titanium carbide and titanium diboride has been applied to hafnium carbide. Presently, the application of this technique results in a moderately dense HfC product. Sample confinement and configuration, explosive loading, and total heat available for the combustionsynthesis process were found to influence product characteristics. The key features of the process as well as some of the properties of the HfC ceramics produced are described. [

Synthesis of Ultra‐Fine Hafnium Carbide Powder and its Pressureless Sintering

“…It has very high melting point (3950°±40°C), low vapor pressure, low electrical resistivity (∼37–45 μΩ·cm), and high chemical stability. It is a desirable material for structures operating at high or ultrahigh temperatures (2000°–3000°C), such as nuclear reactor rods, nuclear rocket propulsion, space air craft, and thermal‐field emitters 2–6 …”

“…Although a wide range of applications are listed, HfC ceramics are hard to be sintered due to strong covalent bonds 2,4,7,8 . Using commercial HfC powder as raw material, hot pressing (HP) at 2200°–2690°C or spark plasma sintering (SPS) technique is required for compacting ceramics 2,9–11 .…”

Structural and mechanical properties of TiB2 and TiC prepared by self-propagating high-temperature synthesis/dynamic compaction

“…The SHS/DC technique has been studied by researchers at the US Army Ballistic Research Laboratory [22][23][24][25], and at New Mexico Tech. [26][27][28].…”

HfC Precursor: Synthesis and Pyrolysis Behavior

“…无 机 材 料 学 报 第 32 卷 学计量比化合物 [1] 。HfC 作为重要的超高温陶瓷材 料之一, 具有高熔点(3890℃)、高硬度、高化学稳定 性、良好的导热和导电性、耐烧蚀和热冲击以及优 异 的 抗 氧 化 性 [2][3] 等 优 点 , 适 用 于 高 温 或 超 高 温 (2000~3000℃)结构材料、 超硬工具材料、 薄膜材料、 微型电子材料及核能储备材料 [4] 。研究表明 [5][6][7][8][9][10][11][12][13][14] , 在 C/C 复合材料中添加难熔金属碳化物(ZrC、HfC、 TaC、WC 等)及硼化物(ZrB 2 、HfB 2 等)可以明显改 善其高温抗烧蚀性能。 HfC 陶瓷的制备方法主要有金属氧化物的碳热 还原反应法 [4] 、 金属与碳的化合反应法 [15] 以及溶胶-凝胶结合碳热还原反应法 [16][17] 。前两种方法存在反 应温度高, 所得 HfC 陶瓷纯度低、粒径大且分布不 均等缺点, 从而限制了它们的工业化应用。溶胶-凝 胶结合碳热还原反应法反应温度相对较低, 制备的 HfC 陶瓷颗粒粒径分布比较均匀。 但是溶胶-凝胶法 得到的前驱体有效浓度低、稳定性差、易沉降和析 出、不易存储, 且其操作复杂、工艺周期长, 不适合 大规模生产。液相有机前驱体转化法克服了溶胶-凝胶法的工艺缺陷, 具有良好的可操控性, 已广泛 应用于制备 ZrC [18] 、TaC [19] 等过渡金属碳化物超细 陶瓷粉体。 然而, 有关采用液相有机前驱体转化法制 备 HfC 陶瓷粉体的研究还鲜有文献报道。 王延斌等 [20] 曾以氯氧化铪、…”