碳复合耐火材料中复合纳米碳与原位形成陶瓷相协同强韧化机理研究

Carbon containing refractory is being developed toward low carbonization in refractory field. With respect to low carbon containing refractory(5%C), all kinds of nano carbons (carbon black, carbon nanotubes and graphene sheets) are regarded as new carbon sources and have a good potential in strenghtening and toughening this kind of material, and then improving thermal shock resistance. With a view to solving the problem of dispersion of nano carbons in matrix of materials and its correlations with in-situ formed ceramic phases, this project proposes to modify or graft multiple nano carbons with organo-functional groups, so that they are evenly dispersed in liquid phenolic resin binder or loaded with transition metal catalyst into the resin. For the latter transition metal catalytically pyrolyzes resin to form multiple nano carbon hybrid structure. By adjusting material composition, optimizing nano carbon hybrid structure, controlling the morphology of in situ formed ceramic phases, nano carbons and in situ formed ceramic phases will produce the strengthening and toughening and their synergistic effect on carbon containing refractory. The research work are mainly to investigate multiple carbon surface modification and hybrid principle, elucidate the processing conditions of catalytic pyrolysis of phenolic resin to form the multiple carbon nano hybrid structure, correlate the morphology of in-situ formed ceramic phase with catalyst species and nano carbon sources, then investigate the effect of multiple nano carbon and in situ formed ceramic phases on the rupture behavior of this kind of refractory, finally reveal the strengthening and toughening mechanisms of multiple carbon and in situ formed ceramic phases to provide a theoretical basis for the preparation of low carbon high performance refractory.

碳复合耐火材料低碳化是当前发展方向，各种纳米碳（炭黑、碳纳米管和石墨烯片）作为新一代碳复合耐火材料的碳源，在提高材料强度和韧性，改善材料热震稳定性方面具有很好潜力。针对复合引入纳米碳在材料中分散性问题和其对原位形成陶瓷相可能产生影响，本项目拟将纳米碳通过表面修饰和杂化处理，使其均匀分散在液态酚醛树脂结合剂中；或将负载有过渡金属催化剂的纳米碳引入树脂，在材料基体中原位催化裂解树脂形成纳米碳杂化结构。通过调整材料的组成，优化纳米碳杂化结构，控制材料中原位形成陶瓷相形貌，发挥纳米碳/原位陶瓷相自身及其协同强韧化作用。研究内容主要包括1）研究各种纳米碳表面修饰及杂化原理；2)探明原位催化裂解酚醛树脂形成纳米碳杂化结构的物理化学条件，建立纳米碳源、催化剂与原位陶瓷相形貌的关联性；3）研究纳米碳/原位陶瓷相对材料断裂行为的影响，揭示纳米碳-原位陶瓷相强韧化机理，为制备高性能低碳耐火材料提供理论依据。

纳米碳作为新一代碳复合耐火材料的碳源，在提高材料强度和韧性，改善材料热震稳定性方面具有很好潜力。本项目针对纳米碳在高温下可能存在氧化、蚀变的问题以及如何发挥纳米碳/原位陶瓷相自身及其协同强韧化作用问题，开展如下主要工作：1）通过硼氮掺杂膨胀石墨修复石墨的晶体结构，提高膨胀石墨的抗氧化性能；通过碳化硅晶须/球状氧化硅修饰膨胀石墨制备多维复合碳源，改善碳源与基体的界面特性；2）采用含铁、镍、钴等作为催化剂原位催化裂解酚醛树脂形成碳纳米管，促进一维纳米碳与其它纳米碳形成杂化复合结构；通过添加碳化硼等防氧化剂，有效地阻止了碳纳米管的结构蚀变；3）采用引入含镍催化剂原位催化形成碳纳米管，通过控制材料中氧分压，促进碳化硅、氧化镁晶须生成；4）利用纳米碳源（炭黑、碳纳米管修、膨胀石墨等）与原位形成陶瓷相碳化硅和氧化镁等协同强化作用，显著提高纳米碳复合耐火材料的强度和抗热震性，并采用楔形劈裂法定量表征材料的抗热震因子，揭示了低碳耐火材料性能参数与抗热震性之间关联性。.本项目提出硼氮掺杂膨胀石墨形成硼碳和氮碳化学键合修复石墨晶格的路线，提高了其石墨化度；提出通过碳化硅晶须/球状二氧化硅修饰膨胀石墨的方法，在原子水平上形成增强体之间的化学键合，开辟了制备复合材料用多维度增强体的新途径；提出采用催化技术在低碳耐火材料中原位形成纳米碳-陶瓷相协同增强增韧耐火材料体系，为低碳耐火材料产业化奠定了理论基础。.获得国家技术发明二等奖和湖北省科技进步一等奖各1项，在国内外重要刊物发表论文35篇，其中SCI检索源刊22篇，EI检索原刊8篇，SCI-2区3篇，SCI-1区19篇，授权发明专利4项，培养硕士1名、博士7名和青年教师2名。本项目部分研究成果已在武汉钢铁（集团）公司和安徽马钢耐火材料有限公司进行了产业化应用，1项专利技术作价入股成立湖南武科立达格拉菲新材料有限公司。