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B_4C/石墨复合粉体的合成及抗氧化性能
作者:李享成 周芬 朱伯铨  
单位:武汉科技大学耐火材料与高温陶瓷国家重点实验室培育基地  
关键词:碳化硼/石墨  合成  抗氧化性  气氛 
分类号:TQ175.1
出版年,卷(期):页码:2010,38(6):1070-1074
DOI:
摘要:

用聚乙烯醇[poly(vinyl alcohol),PVA]、硼酸合成B4C/石墨复合粉体。通过红外光谱,X射线衍射仪及扫描电子显微镜分析复合粉体的显微结构。研究发现:硼酸与PVA形成凝胶,在700℃煅烧2h后生成中间产物B-O-C。中间产物在埋碳气氛下煅烧,只生成石墨而没有B4C;在Ar气氛中于1300℃煅烧5h,能够形成B4C和石墨。加入碳黑有助于合成B4C。合成的B4C颗粒尺寸在1μm以下,石墨的粒度为2~3μm,B4C依附于石墨表面生长。将B4C/石墨复合粉体作为碳源加入Al2O3材料中,在空气中于1200℃煅烧2h后作抗氧化实验。结果表明:氧化层厚度为4.09mm,原始层面积保持在60%以上,显示出抗氧化性能。

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Boron carbide/graphite composite powder was synthesized using poly(vinyl alcohol) (PVA) and boric acid as raw materials. The composite powder was characterized by the Fourier transform infrared spectra,X-ray diffraction and scanning electron micro-scope. The results show that mixed solution of the PVA and boric acid can be dried to form gel and then generate intermediate of B—O—C calcined at 700 ℃ for 2 h in air. When the intermediate is calcined in reducing atmosphere,the graphite can be formed but B4C can not exist. The boron carbide/graphite composite powders are synthesized from the intermediate in Ar atmosphere at 1 300 ℃ for 5 h. What is more,the addition of carbon black can improve the synthesis of B4C. The particle size of B4C is below 1 μm while that of the graphite is 2–3μm. The B4C phase exists on surface of the graphite. The boron carbide/graphite is introduced into Al2O3 materials as carbon resource. The oxidant experiments in air at 1 200 ℃ for 2 h show that the thickness of oxide layer is 4.09 mm and the percent area of non-oxidant layer is above 60%. The boron carbide/graphite composite powders possess the anti-oxidant properties.

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基金项目:
国家自然科学基金(50904048)资助项目
作者简介:
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参考文献:

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