Self-lubricating HPPMS-CrAlN-coatings for the use in dry cold forging processes of steel

冷锻成形制造工艺因其材料利用率高、生产工艺中的能源和资源效率高而具有重要意义。为了使冷锻造过程可控，使用了液体和固体润滑剂，但由于生态、经济和立法原因，这些润滑剂往往是有问题的。正因为如此，干法成形显示出更大的研究潜力。干式摩擦学系统成形过程中润滑剂的减少导致了对润滑剂需求量的增加。这些要求通过与自润滑涂层相结合的合适的表面结构来控制。基于当前技术状态，使用结构化的工件表面与自润滑涂层相结合来描述摩擦学特性的研究还不够深入。因此，我们面临的挑战是探索一种结合在工件表面的减摩结构和刀具上的耐磨自润滑涂层，从而首次实现冷锻造的干式成形。本项目的目的是建立一个模型来解释工件表面形貌和自润滑涂层之间的摩擦学相互作用。所期望的模型应通过涉及摩擦和磨损的经验关系和分析公式来解释低碳钢材料干成形的物理、热和化学机制。在第一步中，将使用HPPMS(高功率脉冲磁控溅射)工艺来制备和表征一种新型的自润滑涂层。进一步的研究重点是开发一种减摩随机表面结构，以减小真实接触面积。在随后的合成中，将研究新开发的HPPMS涂层与结构件表面之间的相互作用。被迫害的假设是，它存在一个摩擦学系统，其特点是特殊的刀具涂层系统与特定的工件结构相结合，从而减少摩擦和磨损。因此，干法成形是可靠和经济可行的。

Forming manufacturing processes of cold forging are of great importance due to the high material utilization and the associated energy and resource efficiency in the production technology. In order to make cold forging processes controllable, liquid and solid lubricants are used, which are often questionable due to ecological, economic and legislative reasons. For this reasons, dry forming exhibits an increased research potential. Abdication of lubricants for dry tribological systems in forming leads to an increase of requirements. These requirements are controlled by suitable surface structures in combination with a self-lubricating coating.The description of the tribological properties using structured workpiece surfaces in combination with a self-lubricating coating based on the current state of the art are insufficiently explored. Therefore, the challenge is to explore a combination of friction-reducing surface structures on the workpieces and a wear resistant, self-lubricating coating on tools, which allows dry forming in cold forging for the first time.The aim of this project is the generation of a model in order to explain the tribological interaction between the workpiece topography and a self-lubricating coating. The aspired model should explain the physical, thermal and chemical mechanisms of dry forming of mild steel materials by empirical relationships and analytical formulations, which involve friction and wear. In a first step, the preparation and characterization of a novel self-lubricating coating using HPPMS (High Power Pulsed Magnetron Sputtering) process will be carried out. A further research focus is the development of a friction-reducing stochastic surface structure in order to reduce the true contact area. In a subsequent composition, the interaction between the newly developed HPPMS coating and structured workpiece surface will be studied. The persecuted hypothesis is, that it exists a tribological system, which is characterized by a special tool coating system in combination with a defined workpiece structure, so that friction and wear are reduced. Dry forming is then reliably and economically feasible.