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

冷锻成形制造工艺具有材料利用率高、能源和资源效率高的特点。为了使冷锻过程可控，使用液体和固体润滑剂，这往往受到生态，经济和立法原因的质疑。由于这个原因，干成型显示出越来越大的研究潜力。干燥摩擦学系统在成形过程中不再使用润滑剂，导致对润滑剂的要求增加。这些要求由合适的表面结构与自润滑涂层相结合来控制。使用结构化工件表面结合基于当前技术状态的自润滑涂层的摩擦学特性的描述没有得到充分的探索。因此，挑战在于探索工件表面减少摩擦结构和工具上耐磨、自润滑涂层的组合，从而首次实现冷锻造中的干成形。该项目的目的是生成一个模型，以解释工件形貌和自润滑涂层之间的摩擦学相互作用。期望的模型应该通过经验关系和涉及摩擦和磨损的分析公式来解释软钢材料干成形的物理、热和化学机制。第一步，采用高功率脉冲磁控溅射（HPPMS）工艺制备一种新型自润滑涂层并进行表征。进一步的研究重点是开发一种减少摩擦的随机表面结构，以减少真正的接触面积。在随后的合成中，将研究新开发的HPPMS涂层与结构化工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，其特征是特殊的刀具涂层系统与确定的工件结构相结合，从而减少摩擦和磨损。然后干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.