采用气流粉碎对Ｂ４Ｃ粗粉（比表面积０．５２ｍ２／ｇ，中位粒径２０．４μｍ）进行了一系列粉碎实验，研究了气流粉碎次数、成形压力和烧结温度对烧结密度的影响．结果表明，当粉碎次数达到３次后，可获得＜１μｍ的Ｂ４Ｃ超细粉末．经过４次气流粉碎的Ｂ４Ｃ超细粉末的比表面积为２．５３ｍ２／ｇ，中位粒径为０．５６μｍ；粉末分别于２２００和２２５０℃压烧结１ｈ，其烧结密度分别达到理论密度的７８．６％和８２．５％，平均晶粒尺寸分别为２８和５０μｍ抗压强度分别为３９０和５５５ＭＰａ．
A series of jet-milling experiments on B4C coarse powders with specific surface area of 0.52m^2/g and median particle size of 20.4μm were carried out. Effects
of jet-milling times, forming stress and sintering temperature on sintered densities of B4C were also studied. The results show that powders with particle size of less than 1μm can be
obtained when jet-milled for more than 3 times. The powders jet-milled for 4 times, with specific surface area of 2.53m2/g and median particle size of 0.56μm,
can be pressureless sintered to 78.6% TD at 2200℃and 82.5% TD at 2250℃ for 1h, with average grain size of 28μm and 50μm, comprasive strength of
390MPa and 555MPa respectively.
参考文献
| [1] | Prochazka S, Dole S L. Development of spacecraft materials and structure fundamentals. AD--A 161338, 1985, 29--39. [2] Schwetz K A, Vogt G. Process for the production of dense sintered shaped articles of polycrystalline boron carbide by pressureless sintering. US Pat 4195066, 1980--03--25 [3] Prochazka S, Dole S L, Hejna C I. J. Am. Ceram. Soc., 1985, 68 (9): 235--236. [4] Prochazka S, Grellner W. J. Less-Common Met., 1981, 82: 37--47. [5] Thevenot F. J. Nucl Mater., 1988, 152: 154--162. [6] 王零森, 蒋辉珍, 杨菊美, 等. 中南矿冶学院学报, 1985, 16 (4): 66--72. [7] 卢寿慈主编. 粉体加工技术. 北京: 中国轻工业出版社, 1999. 121--134. |
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