多层梯度多元掺杂ta-C纳米复合涂层制备与切削性能研究

The structure and property of ta-C (sp3 > 80%) are very close to that of diamond (sp3 100%). Accordingly, ta-C possesses high hardness and wear resistance, low friction self-lubricating, good thermal stability, as well as the advantages of low temperature deposition. However, high internal stress, low adhesion, weak toughness, and difficult to large area deposition limit the application on cutting tools of ta-C. However, the high compressive residual stress, low adhesion, low toughness, and difficult to large-area deposition have become the main obstacles to the applications of ta-C coatings. In this project, multiple metal atoms doping as well as multilayer structure will be used to improve the ta-C properties. Novel high ionization HIPIMS will be used to prepare the nanocomposite ta-C multilayer coating which consists of multi-nanoparticles, grain boundaries and gradient structures. The influences of the coating deposition parameters, metal doping and coating thickness on the coating structure, physical properties, mechanical properties and tribological properties will be studied carefully. This project aims to obtain the high quality ta-C coatings with a low stress, high hardness, wear resistance and self-lubrication, good toughness and adhesion, and the corresponding large-area and low cost preparation method and technology of ta-C coatings. The ta-C coatings with excellent properties will be applied to the cutting tools.

四面体非晶碳ta-C的sp3键含量超80%，结构和性能非常接近金刚石（100% sp3），具极高的硬度和耐磨性、低摩擦自润滑、热稳定性好，以及低温沉积等优点，但高内应力、低膜基结合力、韧性差、以及难以大面积沉积等因素限制了其在涂层刀具上的使用。本项目拟采用金属掺杂对ta-C进行改性，结合多层多元掺杂纳米复合设计方法，系统组合具有不同优异性能的金属掺杂ta-C涂层，采用高离化率、高功率氖磁控溅射技术制备由多元掺杂、多纳米颗粒、多晶界复合与多层梯度结构耦合的ta-C涂层，研究涂层工艺条件、掺杂元素种类和含量、膜层厚度和体系对涂层组织结构、物理性能、机械性能和摩擦磨损特性的影响，最终获得具有低应力、高硬度、耐磨润滑、韧性好、结合力好等综合性能优异的多层多元掺杂ta-C纳米复合涂层和相应大面积、低成本的制备方法和工艺，并应用于涂层刀具切削加工。

碳基涂层（如类金刚石DLC、非晶金刚石ta-C等）具有极高的硬度和耐磨性、低摩擦系数和热膨胀系数、高弹性模量、良好的化学稳定性以及与非铁族亲和弱等优异性能，被广泛应用于微钻、模具、精密零部件、微电子等领域。但高残余应力、膜基结合弱、抗冲击韧性不足、摩擦性能不稳、以及难以大面积制备等问题，限制了其在涂层刀具上的应用。本项目主要利用高功率脉冲复合磁控溅射，系统研究单一金属掺杂和多元金属掺杂对DLC涂层结构和性能的影响；依据不同金属掺入DLC中化学状态和存在形式以及其对DLC性能的影响，系统选择碳化物形成元素Cr、Ti，弱碳化物形成元素Al、Cu以及非金属元素Si等进行多元金属掺杂，构筑多元多层纳米复合DLC涂层；系统研究沉积参数、掺杂元素种类和含量对涂层组织结构和性能的影响；同时针对磁控溅射C离化率低的问题，采用高功率脉冲磁控溅射和Ne溅射气体获得高质量DLC涂层；最后对DLC涂层刀具在高速切削高硅铝合金特性及金属掺杂、多层结构对DLC涂层刀具切削性能影响进行了研究，构建DLC涂层刀具设计、性能与切削性能之间的相关关系。