DFG Schtein – Development of PVD-coated tools made of rock

The production of conventional cutting materials, such as cemented carbides, requires critical raw materials such as cobalt and tungsten. To reduce dependence on these elements and minimize ethical and supply-related risks, the range of cutting materials must be expanded. Cutting materials must combine hardness, heat resistance, and toughness; compromises are necessary in practice. Rocks are rarely considered in this context. We have already demonstrated the potential of high-silicon rocks as cutting materials for plastics and aluminum alloys (DFG project: Production and Application Behavior of Cutting Tools Made from Rocks). Combining rocks as cutting materials with modern PVD coatings can increase their usability and ecologically expand the established range of cutting materials.

Objectives

The production of conventional cutting materials such as cemented carbide requires ecologically and economically questionable raw materials, tungsten and cobalt. By expanding the range of cutting materials, dependence on these materials can be reduced. Naturally occurring rocks offer potential in this area. PVD coatings could enhance their usability. The influence of mechanical and chemical coating pretreatment processes on the surface zone, coatability, and coating adhesion is investigated using selected stones. Based on this understanding, it is then possible to identify suitable coating systems for rocks. The mechanisms of coating adhesion based on residual stress and layer morphology are investigated. Finally, coated rock tools are used in turning aluminum alloys, and the coating failure mechanisms are characterized using a wear analysis.

Benefits

• Expansion of the cutting material product range
• Energy-efficient cutting materials with high availability
• Ecologically and economically sustainable cutting materials

Approach

In the DFG project "Schtein – Development of PVD-coated tools made of rock," we are developing and researching the coatability of cutting tools made from rock together with TU Dortmund University. The focus is on the influence of mechanical and chemical coating pretreatment processes on the surface zone, coatability, and coating adhesion. Finally, coated rock tools will be used in turning aluminum alloys, and the coating failure mechanisms will be characterized using a wear analysis.

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Contact Hilke Petersen via email at hilke.petersen@ifw.uni.hannover.de or by phone at +49 511 762 18724.