基于贻贝粘蛋白的仿生石墨烯/金刚石复合涂层微细刀具制备方法与应用基础研究

In order to meet the urgent demand of surface modification of diamond coated micro end mills for precision cutting of aspherical ceramic molds, mussel adhesive protein was used in this project to realize the strong bonding between graphene and diamond with cross-linking, thus the innovative mussel-inspired graphene modified diamond coating was prepared. The mussel-inspired graphene coating enhanced the surface smoothness and friction reducing properties of diamond coating significantly with no apparent increase in thickness, which was attributed to the synergistic friction reducing effect of the natural surface texture on diamond coating and graphene flakes. This could provide an innovative tool solution for high-efficiency and high-precision machining of silicon carbide micro molds. The preparation methods of mussel-inspired graphene/diamond composite coating, the chemical bonding mechanism among mussel protein, graphene and diamond, the synergistic friction reduction mechanism of graphene, mussel protein and diamond coatings, and the wear mechanism and surface formation mechanism of the mussel-inspired graphene/diamond composite coated micro end mill were studied. The research results have important academic value and application prospects for the application of graphene coating at macro-scale, friction reduction technology on cutting tool surface and micro-processing technology on hard-brittle materials.

针对高精密非球面碳化硅微型模具高效精密加工对金刚石涂层微铣刀表面改性的迫切需求，本项目采用贻贝粘蛋白（Mussel Adhesive Protein）实现石墨烯与金刚石之间基于化学交联（Cross-linking）的强结合作用，利用金刚石涂层天然的微织构表面与石墨烯片层之间优异的协同减摩特性，制备创新性的仿生石墨烯/金刚石复合涂层，在不增加涂层厚度的前提下显著增强金刚石涂层微铣刀的表面光滑性与减摩特性，为碳化硅微型模具高效精密加工提供创新性的刀具解决方案。围绕仿生石墨烯/金刚石复合涂层制备方法，贻贝粘蛋白与石墨烯和金刚石之间的化学结合机制，石墨烯-贻贝粘蛋白-金刚石涂层协同减摩机理，以及仿生石墨烯/金刚石复合涂层微铣刀的磨损机制与加工表面创成机理等四个方面开展研究。研究成果对宏观石墨烯涂层应用、切削刀具表面减摩技术以及硬脆性难加工材料微细加工技术等领域的研究均具有重要的学术价值和应用前景。

针对CVD金刚石涂层在介观尺度加工表面质量不足的问题，本项目创新性地提出采用贻贝粘蛋白仿生石墨烯涂层（MAP/Gr）对传统微米/亚微米金刚石涂层进行表面改性，在不明显增加涂层厚度的前提下显著提高金刚石涂层的表面光滑性与减摩特性。主要研究内容包括：1）基于循环吸附法和电泳沉积法成功制备了贻贝粘蛋白仿生石墨烯涂层；采用扫描电镜、拉曼光谱、红外光谱仪等对MAP/Gr涂层的表面形貌及结构成分进行了系统性的表征；揭示了仿生石墨烯涂层内部石墨烯及贻贝粘蛋白的分布和结合机理。2）考察了贻贝粘蛋白缓冲液参数，包括pH值、浸泡时间，石墨烯片层缺陷以及基体界面官能团对贻贝粘蛋白/石墨烯的吸附密度、吸附强度等性能指标的影响，优化仿生石墨烯制备工艺使石墨烯与基体结合能提升了6.6倍；采用AFM微观摩擦实验和分子动力学模拟的手段研究了石墨烯和仿生石墨烯的微观磨损行为机理。3）考察了电泳沉积仿生石墨烯涂层和循环吸附仿生石墨烯涂层在宏观条件下的摩擦学行为，揭示了摩擦过程中仿生石墨烯涂层的表面结构成分演化规律以及石墨烯、贻贝粘蛋白与金刚石涂层三者之间的协同作用机制，仿生石墨烯涂层表面减摩效应的服役寿命可长达490000 循环以上，比传统石墨烯涂层提升100倍以上，与金刚石涂层相结合可获得低至0.05的摩擦系数。4）采用HFCVD法与循环吸附法在复杂形状微铣刀表面制备了仿生石墨烯/金刚石复合涂层，石墨烯对提升MCD涂层微铣刀的加工表面质量具有非常显著的效果，但传统的石墨烯涂层由于附着力限制导致其服役寿命有限，贻贝粘蛋白仿生石墨烯可以提供长效优异的减摩作用。上述研究成果可为提升金刚石涂层微铣刀在介观尺度下硬脆性难加工材料领域的加工水平奠定理论基础，具有重要的学术研究价值和应用前景。