A novel development of sustainable cutting inserts based on PVD-coated natural rocks

Abstract

The demand for modern cutting tool materials poses significant challenges due to their high energy consumption and reliance on expensive raw materials, which can have adverse effects on the environment, economic development, and geopolitical conditions. In response to these challenges, natural rocks are proposed as a sustainable and cost-effective alternative cutting tool material. By employing physical vapor deposition (PVD) technology to apply hard coatings onto natural rocks, their suitability as cutting inserts can be enhanced, thereby improving cutting performance. Titanium nitride (TiN) coatings were deposited on various types of natural rocks by magnetron sputtering. The natural rocks Alta quartzite, flint, lamellar obsidian, quartz, and Silver quartzite were utilized as substrate materials. The TiN coatings exhibit a crystalline structure on all rock inserts and significantly increase the surface hardness. Cutting tests using the PVD-coated rock inserts revealed enhanced wear resistance due to the TiN coating. However, the cutting performance was notably influenced by the distinct material properties of the natural rocks. Among them, flint as a substrate material ensures the highest wear resistance over an extended cutting length. Consequently, the utilization of PVD-coated natural rocks as cutting tools offers a novel concept to expand the group of cutting materials and provide a sustainable cutting material.