PVD wear protection coatings as thermal insulation and diffusion barrier for PCD cutting tools (DiaCoat)

 

The aim of the research project is the development and use of diffusion-inhibiting and heat-insulating coatings via physical vapor deposition (PVD) for tools with cutting edges consisting of polycrystalline diamond (PCD) to improve performance in the turning and milling of cast materials. Cast iron is one of the most widely used ferrous materials. However, diamond's affinity for ferrous materials and challenging coatability lead to rapidly progressing tribochemical wear during machining. Therefore, PCD cutting materials cannot be used economically in the machining of cast alloys so far.

To implement the objective, coatings are being developed that protect the substrate from thermal and chemical wear. The research work includes, among other things, investigations into the coating structure and the process parameters for coating deposition. In addition, a knowledge base will be created to describe the influence of coating properties (thermal conductivity, coefficient of friction, hardness, etc.) on wear behavior and mechanisms, thermomechanical tool loading, chip formation and shape, and component quality. As a result, recommendations for SMEs on the deposition of PVD coatings on PCD tools as well as process parameters for the machining of cast alloys are obtained. This offers SMEs the potential to respond flexibly to challenges in cast machining and at the same time to exploit the economic potential of diamond cutting materials for machining. Based on the knowledge base developed, an economic benefit is generated, for example, through longer tool life and more stable machining processes, which far exceeds the additional costs for tool procurement. The use of the newly developed technologies and heat-insulating coatings will also reduce downtimes and scrap at the SMEs, which means that production processes can be designed more cost-effectively. The immediate implementation of the project results in industrial practice is possible, since no additional integration effort on the machine side and no change of the tool geometry are necessary for the realization. Therefore, there is the possibility that the results will be transferred and implemented in practice directly after the project period.