A New Strategy for the Design of Wear Resistant Nitride Coatings for Dry Machining

该奖项的研究目标是探索刀具涂层的新概念，使钢和其他难切割的金属合金能够进行干式高速加工。方法是设计既能抵抗高温氧化又能抵抗扩散磨损机制的涂层。目前最先进的涂料主要是基于其抗氧化性而得到提升的。使用在待加工的工件中具有有限溶解度的大金属氮化物化合物，可以实现对基于扩散的磨损机制的抵抗。由于高速加工操作同时受到氧化和扩散磨损的影响，因此将研究由大金属氮化物和抗氧化氮化物交替形成的多层涂层。将这些涂层沉积成纳米多层膜还可以提高涂层的硬度和抗裂性。还将进行溅射沉积，并对沉积的涂层进行全面的化学和机械表征。将进行研究，以评估这些涂层在钢的高速车削过程中的性能。这项研究的社会效益将通过推广干式加工代替润滑加工来实现。对于使用切削液的机械加工操作，环境和健康问题都被提出了。切削液的处置已变得更加规范，因此对金属切削业来说成本更高。这项研究中将要检验的涂层的成功将使润滑剂的使用量大大减少，在某些情况下，在切割过程中完全消除切削液。

The research objective of this award is to investigate a new concept in coatings for cutting tools that will enable dry, high-speed machining of steels and other hard-to-cut metal alloys. The approach is to design coatings that are resistant to both high-temperature oxidation and diffusion-based wear mechanisms. Current state-of-the art coatings have been promoted based primarily on their oxidation resistance. Resistance to diffusion-based wear mechanisms will be achieved using large-metal nitride compounds that have a limited solubility within the work piece to be machined. Since high-speed machining operations are subject to both oxidative and diffusion wear, multilayer coatings that are structured as alternating layers of large-metal nitrides with oxidation-resistant nitrides will be investigated. Depositing these coatings as nano-scale multilayers will also enhance the hardness and fracture resistance of the coatings. Sputter deposition and full chemical and mechanical characterization of the deposited coatings also will be carried out. Research will be conducted to evaluate the performance of these coatings during high-speed turning of steel. The societal benefits of the research will be realized through the promotion of dry machining in place of lubricated machining. Both environmental and health concerns have been raised for machining operations that use cutting fluids. The disposal of cutting fluids has become more regulated and therefore more costly for the metal cutting industry. The success of the coatings to be examined in this study will enable a substantial reduction in the quantity of lubricant used, and in some cases complete elimination of cutting fluids during cutting.