一种高产率低温合成碳化硼粉体的方法

Method for synthesizing boron carbide powder in high yield at low temperature

Abstract

The invention relates to a method for synthesizing boron carbide powder in high yield at low temperature. The method comprises the following steps: respectively measuring boric acid and polyvinyl alcohol according to a molar ratio of (4 to 7) : 10, mixing and stirring the boric acid and glycerol to be completely dissolved, adding alkali, adjusting the pH to 4 to 6, and obtaining a boric acid solution; mixing and stirring the polyvinyl alcohol and water to be completely dissolved, and obtaining a polyvinyl alcohol solution; mixing and stirring the obtained boric acid solution and the obtained polyvinyl alcohol solution, and heating and evaporating a solvent to completely form gel; drying the obtained gel to obtain dry gel; preserving the heat of the dry gel for 2 to 4 hours in a vacuum or inert atmosphere at the temperature of 500 to 700 DEG C, and carrying out the dissociation; preserving the heat of a dissociation product in a vacuum or inert atmosphere at the temperature of 1300 to 1500 DEG C for 3 to 5 hours, and carrying out the carbon thermal reduction for the dissociation product, and obtaining boron carbide powder. By adopting the method, the problems that B2O3 is severely volatilized and lost and the concentration of boric acid in a boric acid-polyvinyl alcohol system is extremely low in the subsequent process of gel of a boric acid-glycerol system are simultaneously overcome.
本发明涉及一种高产率低温合成碳化硼粉体的方法,包括:按(4~7):10的摩尔配比分别称取硼酸和聚乙烯醇,将硼酸与丙三醇混合搅拌至完全溶解,加入碱调节pH至4~6,得到硼酸溶液;将聚乙烯醇与水混合搅拌至完全溶解,得到聚乙烯醇溶液;将所得硼酸溶液和所得聚乙烯醇溶液混合搅拌并在加热下蒸发溶剂至完全形成凝胶;将所得凝胶进行干燥,得到干凝胶;将所得干凝胶在真空或惰性气氛下于500~700℃保温2~4小时进行裂解;将裂解产物在真空或惰性气氛下于1300~1500℃保温3~5小时进行碳热还原,得到碳化硼粉体。本发明同时克服了硼酸-丙三醇体系凝胶后续处理过程中B2O3挥发损耗严重和硼酸-聚乙烯醇体系硼酸浓度过低的局限。

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Patent Citations (1)

    Publication numberPublication dateAssigneeTitle
    CN-102674356-ASeptember 19, 2012山东大学一种纳米富<sup>10</sup>B碳化硼粉体的制备方法

NO-Patent Citations (1)

    Title
    张云霏等: "碳化硼微粉的低温合成", 《无机盐工业》

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