具有遗传特性二维Ti3C2烯及其复合材料的制备和性能研究

Ti3C2-MXene is a new type of graphene-like and two-dimensional material. It has attracted much attention due to its high specific surface areas, excellent mechanical，electrical and catalytic properties. Ti3C2-MXene has metallic characters so it can form a strong bonding interface with metals at sintering temperatures. The strong bonding interface, being impossibly achieved in graphene/metal composites due to the poor wettability between graphene and metals, will endow Ti3C2-reinforced metal matrix composites with enhanced properties. In this project, Ti3C2-MXene will be prepared in a large scale in lab after the optimization of synthesis conditions, and then new Ti3C2/Cu or Ti3C2/Al metal matrix composites will be fabricated. The research will focus on the detachment of functional groups in the Ti3C2-MXene, the thermal stability of Ti3C2-MXene at high temperatures, the wettability and compatibility of Ti3C2-MXene with metals at sintering temperatures, and the homogeneous distribution of Ti3C2-MXene in composites. Furthermore, mechanical properties, electrical conductivity and wear behavior of Ti3C2/Cu or Ti3C2/Al composites will be investigated. At last, interfaces between Ti3C2 and metals are to be determined, a relationship of process-structure-property will be elucidated, and the main mechanisms of the improved Ti3C2/Cu or Ti3C2/Al composites are to be also explained. The benefits of this project are obvious to achieve innovative results and to improve our country’s international competitiveness in the research and applications of MXene materials.

Ti3C2烯是一种新型“类石墨烯”二维材料，它具有高比表面积、优异的力学、电学、催化等性能而备受关注。尤其是Ti3C2烯具有金属特性，它作为增强相可与Cu等金属形成强结合界面（这种界面是石墨烯与金属因存在润湿性差而无法获得的），有望得到综合性能优良的新型Ti3C2烯增强金属基复合材料。本项目在优化工艺的基础上，批量获得Ti3C2烯粉体；率先开展新型Ti3C2烯增强Cu或Al金属基复合材料。重点研究Ti3C2烯表面官能团的脱附和Ti3C2烯热力学稳定性、Ti3C2烯与金属的润湿性和相容性、以及Ti3C2烯在金属基体中的分布均匀性等关键科学问题；研究复合材料的力学性能、电性能以及摩擦学性能；确定Ti3C2烯与金属基体的界面关系，阐明新型复合材料的“工艺-结构-性能”关系，揭示Ti3C2烯增强金属基复合材料的相关机制。该项目能取得创新性成果，有助于提高我国在MXene新材料领域的国际竞争力。

新型Ti3C2Tx具有高导电、优异的催化和电化学等性能，是继石墨烯后最具吸引力的二维纳米材料。本项目确定关键参数，在40%HF溶液中50℃刻蚀Ti3AlC2，经30min短时间获得了Ti3C2Tx。Ti3C2Tx于空气中300℃以上发生氧化，在真空中800℃以上开始氧化并且相变生成TiC。利用化学镀表面改性技术，获得了“核壳”结构Ti3C2Tx@Ni粉体，Ni壳层的高导电和磁性赋予Ti3C2Tx多功能化。.Ti3C2Tx与Cu或Al的相容性研究表明，Ti3C2Tx于800℃发生相变并与Cu在900℃发生反应，故低于800℃难以制备致密复合材料，高于此温度难以形成Ti3C2Tx/Cu。Ti3C2Tx与Al在650℃以下稳定，无反应发生。因此在650℃无压烧结保温1h，随后经450℃热挤压，获得了结构均匀、界面结合好、性能优良的Ti3C2Tx/Al材料。Ti3C2Tx含量在0.5-3wt.%范围内增加，复合材料力学性能呈直线增加。3wt.%Ti3C2Tx/Al的硬度和强度分别为0.52GPa和148MPa，比纯Al分别提高了92%和50%，但材料延展性降低。而相同工艺制备的新型3wt.%Ti3C2Tx@Ni/Al比3wt.%Ti3C2Tx/Al的强度和延伸率分别提高了10%和8%。另外，3wt.%Ti3C2Tx/Al复合材料具有比Al更低的摩擦系数和更好的耐磨损性能。.Ti3C2Tx和Ti3C2Tx@Ni粉体具有优良的电磁屏蔽性能，其机制是高导电、纳米层状结构和表面官能团对电磁波的多重反射和吸收。Ti3C2Tx@Ni的电磁屏蔽性能由于前者，主要是增加了Ni壳层的磁损耗机制。所制备的Ti3C2Tx/Al和Ti3C2Tx@Ni/Al亦表现出比纯Al更优的电磁屏蔽性能。.采用室温等离子氮化技术对Ti3C2Tx表面改性，经3分钟处理，粉体具有最佳阻抗匹配，吸波性能高达-59dB。此外，项目还开展了MAX和MAB材料的前沿热点研究，亦取得了创新性成果。