Abstract In this research, the B4C nanopowder was synthesized through sol-gel method. Nanometric size of precursors were controlled through dispersing agents and controlling pH inside the sol. Mixing the ingredients in molecular size was one of the important reasons in decreasing synthesis temperature of boron carbide particles. In order to evaluate product formation mechanism during sol-gel process, TEM, SEM, DTA/TG, BET, XPS, FTIR and DLS analysis methods were employed. DLS analysis revealed that precursor's particles inside the Sol were below 10 nm. FTIR analysis on chemical bonds indicated that the B-O-C bond was formed inside the gel powder. DTA analysis demonstrated that B4 C powder particles were formed at the temperature around 1270 °C. Superficial investigations illustrated that the specific surface area of the synthesized B4 C particles is equivalent to 154 m2/g, and also the surfaces of these particles were porous. Further, the size of these cavities is in the meso range. Structural images showed that particles were less than 30 nm. These particles morphology were depend on storage time at the heating stage, as with increasing synthesis time the growth mechanism changes while spherical form of particle shapes converts to whisker.

中文翻译：

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B4C纳米粉体的溶胶-凝胶合成与表征

摘要 本研究采用溶胶-凝胶法合成了B4C纳米粉体。通过分散剂和控制溶胶内的 pH 值来控制前体的纳米尺寸。分子大小的成分混合是降低碳化硼颗粒合成温度的重要原因之一。为了评估溶胶-凝胶过程中的产物形成机制，采用了 TEM、SEM、DTA/TG、BET、XPS、FTIR 和 DLS 分析方法。DLS 分析表明溶胶内的前驱体颗粒小于 10 nm。对化学键的 FTIR 分析表明 BOC 键是在凝胶粉末内部形成的。DTA 分析表明 B4 C 粉末颗粒是在 1270 °C 左右的温度下形成的。表面研究表明，合成的 B4 C 颗粒的比表面积相当于 154 m2/g，而且这些颗粒的表面是多孔的。此外，这些空腔的尺寸在中间范围内。结构图像显示颗粒小于30nm。这些颗粒形态取决于加热阶段的储存时间，因为随着合成时间的增加，生长机制发生变化，而颗粒形状的球形转变为晶须。