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首页> 外文期刊>Journal of Materials Engineering and Performance >The Effect of Crystallinity of Carbon Source on Mechanically Activated Carbothermic Synthesis of Nano-Sized SiC Powders
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The Effect of Crystallinity of Carbon Source on Mechanically Activated Carbothermic Synthesis of Nano-Sized SiC Powders

机译：碳源结晶度对纳米碳化硅粉机械活化碳热合成的影响

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摘要

The relevance of the structure of carbon materials and milling on the carbothermic reduction of silica to produce nano-sized silicon carbide (SiC) was studied. Graphite (crystalline) and metallurgical coke (mainly amorphous) were chosen as carbon precursors that were mixed with amorphous pure nano-sized SiO_2 and milled for different times. The SiC yield at 1450℃ for 1 h was influenced by the degree of milling. Extending the milling time increased SiC formation in both cases. Although some extensive milling converted both sources of carbon into amorphous phase, the amount of synthesized SiC from graphite was about 4.5-3 times higher than coke with increased extent of milling. Graphite is converted from stable crystalline state into the amorphous phase, so it absorbs more activation energy of milling and fresher active centers are created, while the already amorphous coke absorbs less energy and thus less fresh active centers are created. This energy difference acts as a driving force, resulting in higher yield of nano-sized SiC when graphite is used as carbon source.
机译：研究了碳材料的结构和研磨对二氧化硅碳热还原以生产纳米级碳化硅（SiC）的相关性。选择石墨（晶体）和冶金焦（主要是非晶态）作为碳前驱体，将其与非晶态纯纳米SiO_2混合并研磨不同的时间。在1450℃1 h的SiC收率受研磨程度的影响。在两种情况下，延长研磨时间都会增加SiC的形成。尽管一些广泛的研磨将两种碳源都转化为非晶相，但随着研磨程度的增加，由石墨合成的SiC的量比焦炭高约4.5-3倍。石墨从稳定的结晶态转变为非晶态，因此它吸收了更多的研磨活化能，并创建了更新鲜的活性中心，而已经无定形的焦炭吸收了更少的能量，因此创建了更少的新鲜活性中心。当石墨用作碳源时，这种能量差充当驱动力，从而导致纳米级SiC的更高产率。

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