石墨烯-烷烃固液混合介质脉冲放电制备石墨烯/碳化钛复合涂层及其摩擦磨损特性研究

Due to the high hardness, good wear resistance and excellent chemical stability, titanium carbide coatings have prosperous applications as cutting or drilling tools, and moulds. Intrinsic brittleness and high frication coefficient, however, become the bottlenecks of their further development. Considering the excellent mechanical and self-lubricating properties, we propose to introduce the graphene as the second phase into titanium carbide matrix and fabricate these novel composite coatings by electrical discharge coating (EDC) technique using graphene suspended alkane dielectric. There are four main parts of research work in this project: research on a novel graphene suspended alkane dielectric for the preparation of graphene/titanium carbide composite coatings by EDC, the process and control of simultaneous deposition between titanium carbide formed by electrical discharge and graphene suspended in alkane dielectric, the effect of EDC parameters on the microstructure and mechanical properties of the obtained composite coatings, and their tribological behavior and wear properties. This project will well explain the formation mechanism of graphene/titanium carbide composite coatings obtained by EDC using the graphene suspended alkane dielectric, find out the control law of EDC parameters towards the microstructure and mechanical properties of the composite coatings and establish the correlation between coating preparation parameters, microstructure and tribological performance, providing theoretical basis and key techniques for the preparation of titanium carbide based composite coatings with low frication coefficient, good fracture toughness and excellent wear resistance.

由于硬度高、耐磨性和化学稳定性好等优点碳化钛涂层在切削刀具、钻头、模具等场合有广阔的应用前景。然而本征脆性大和摩擦系数高的缺点严重阻碍了碳化钛涂层进一步的发展。鉴于石墨烯优异的力学性能和自润滑特性，本项目率先提出把石墨烯作为增韧和减摩第二相复合到碳化钛涂层中，并提出通过在石墨烯-烷烃固液混合介质中脉冲放电沉积的方法制备此类新型的石墨烯/碳化钛复合涂层。项目围绕脉冲放电沉积用高分散稳定性石墨烯-烷烃固液混合介质的研制、脉冲放电条件下放电点碳化钛与混合介质中石墨烯共沉积的过程与控制、工艺参数对复合涂层组织结构和力学性能的影响、复合涂层摩擦磨损性能四个方面展开研究。项目将阐明复合涂层的形成机理；找出工艺参数调控复合涂层组织结构和力学性能的规律；建立复合涂层制备工艺-组织结构-摩擦磨损性能三者间的关联，为研发新型高性能碳化钛基复合涂层提供理论依据和关键制备技术。

由于硬度高、耐磨性和化学稳定性好等优点碳化钛颗粒增强金属基复合涂层在切削刀具、钻头、模具表面强化等方面有广阔的应用前景。本项目以石墨烯-烷烃固液混合液为工作介质，配合脉冲火花放电技术快速、较低成本地在钢铁基体表面制备出组织致密、膜/基结合力好且厚度较大的碳化钛颗粒增强铁基复合涂层。项目重点围绕以下三个方面展开了详尽的研究：（1）高分散稳定性的石墨烯-烷烃固液混合介质的研制，（2）石墨烯-烷烃固液混合介质对碳化钛颗粒增强铁基复合涂层的形成缺陷、显微组织、力学性能的作用规律，（3）碳化钛颗粒增强铁基复合涂层制备工艺-组织结构-摩擦磨损性能三者间的关联。结果表明石墨烯经十八胺表面改性后可以稳定地分散于电火花成形机床常用的工作介质中。此外，石墨烯的加入有效地分散了脉冲火花放电弧的能量，从而减少裂纹、微孔等涂层形成缺陷。最后，在优化的工艺参数下，可以获得多颗径且分级分布的碳化钛颗粒增强铁基复合涂层。此独特的显微结构有效提高了复合涂层的粘着磨损、磨粒磨损和疲劳磨损抗力，从而减少涂层的摩擦因数和磨损率。项目研究结果为研发新型高性能碳化钛颗粒增强金属基复合涂层提供理论依据和关键制备技术。