Gubernat Agnieszka, Kornaus Kamil, Lach Radosław, Zientara Dariusz, Dyl Patryk
Faculty of Materials Science and Ceramics, Department of Ceramics and Refractories, AGH University of Science and Technology, Mickiewicza Av. 30, 30-059 Kraków, Poland.
Materials (Basel). 2022 Feb 17;15(4):1500. doi: 10.3390/ma15041500.
This paper presents novel results of research focused on reaction sintering of a mixture of expanded graphite and amorphous boron. It has been shown that as a result of combining the synthesis from the elements with sintering under pressure, dense boron carbide polycrystals (95% TD) can be obtained in which stable structures dominate, i.e., boron carbides of stoichiometry BC and BC. Sintering was carried out on boron excess systems, and reaction mixtures with the following mass ratios (B:C = 5:1; 10:1; and 15:1) were used. Boron excess systems were used due to the presence of additional carbon during sintering since the matrix, reactor lining, and heating elements were made of graphite. 1850 °C was considered to be the optimum reaction sintering temperature for all of the systems tested. This shows that a reduction in the sintering temperature of 200-300 °C was observed with respect to traditional sintering techniques. Micro-cracks are present in the sinters, the presence of which is most likely due to the difficulty in removing the gaseous products which accompany the boron carbide synthesis reaction. The elimination of these defects of sintering requires further research.
本文介绍了聚焦于膨胀石墨与非晶硼混合物反应烧结的全新研究成果。结果表明，通过将元素合成与压力烧结相结合，可获得致密的碳化硼多晶体（理论密度的95%），其中稳定结构占主导，即化学计量比为BC和BC的碳化硼。烧结在硼过量体系上进行，并使用了质量比为（B:C = 5:1；10:1；15:1）的反应混合物。由于烧结过程中存在额外的碳，所以采用硼过量体系，因为基体、反应器衬里和加热元件均由石墨制成。1850℃被认为是所有测试体系的最佳反应烧结温度。这表明，相较于传统烧结技术，烧结温度降低了200 - 300℃。烧结体中存在微裂纹，其存在很可能是由于难以去除伴随碳化硼合成反应产生的气态产物。消除这些烧结缺陷需要进一步研究。
