煤沥青改性中间相炭微球制备高密高强石墨的研究

刘洪波 秦冬杰 陈惠 刘金平 杨程 侯冬冬

摘 要：为解决低粘结组分中间相炭微球（MCMB）自烧结性较差的问题，采用热分析和扫描电镜等表征方法，研究了煤沥青种类对改性MCMB粉体烧结性能及其所制备的石墨材料性能的影响.结果表明，采用溶液混合法可在MCMB粉体（D50=23 μm）表面均匀包覆一层煤沥青，并显著提高了低粘结组分MCMB粉体的烧结性能.以改性MCMB粉体为原料经等静压成型、焙烧和石墨化处理所制备的石墨材料均匀致密，抗折强度明显高于以未经改性处理的MCMB粉体为原料制备的石墨材料（22 MPa），并按改性用高温沥青、改质沥青和中温沥青的顺序依次升高，分别为27.7 MPa、42.7 MPa和56.9 MPa.

关键词：煤沥青；中间相炭微球；高密高强石墨材料；力学性能

中图分类号：TB332 文献标志码：A

Abstract：To deal with the problem of mesophase microbeads（MCMB） with a poor sinterability in less binder， thermal analysis and SEM were used to study the influence of different types of coal tar pitch on the sinterability of MCMB powder and performance of the graphite bulks. The results demonstrate that coal tar pitch can coat the surface of the MCMB（D50=23 μm） uniformly by dissolving the pitch and blending the mixture， so that the modified MCMB was obtained and the sinterability was improved. The graphite prepared from the modified MCMB was obtained by successive process of isostatic pressing， baking and graphitization， which had a dense and uniform micro-structure. And the flexural strength of the materials was obviously higher than those（22 MPa） made of unmodified MCMBs， and it increased to 27.7 MPa，42.7 MPa and 56.9 MPa，corresponding to the sequence of high softing pitch，modified pitch and middle softing pitch， respectively.

Key words：coal tar pitch； MCMB； high-density and high-strength graphite materials；mechanical properties

中間相炭微球（MCMB）是采用特殊方式从沥青母体中分离出来的微米级（5～100 μm）各向异性小球体[1]，由于具有形状规则、堆积密度高、易石墨化等优点，已成为制备活性炭、催化剂载体、锂离子电池负极等高性能炭材料的优质前驱体[2].此外，由于其一定的自烧结性，在制备高密度高强度石墨材料方面的应用也引起了研究者的广泛关注[3].

对MCMB进行改性处理是改善其自烧结性的主要途径.常用的改性方法是对MCMB进行预氧化处理调节β树脂的含量、粘度、含氧量来改善其自烧结性能[4-5]，但该法仅适合于β树脂含量较高的MCMB，且生产效率低、成本高；对α树脂含量较低、自烧结性较差的MCMB通常采用超细化 [6-7]和添加粘结剂[8-9]等方法进行改性……