Recent progress in superdhard nanocomposites: Preparation, properties and industrial applications

Advantages and drawbacks of different techniques for the preparation of superhard coatings are briefly summarized with emphasis on high thermal stability and oxidation resistance. It is shown that the hardening by energetic ion bombardment yields coatings with a too low thermal stability whereas the hardness and nanostructure of the superhard nanocomposites prepared according to our generic design principle remain stable up to greater than or equal to 1100 degreesC. The lack of success of some researchers to reproduce our results is due to either an incorrect choice of the deposition conditions (too low nitrogen pressure and/or deposition temperature), or impurities, or a combination of those. The recent progress in the development of the coating technology and industrialization of the nc-(Al1-xTix)N/a-Si3N4 coatings is briefly summarized. The new Lateral Rotating arc Cathode, LARC(R) that uses Virtual Shutter(R) for pre-cleaning of the cathodes is presented together with an example of excellent cutting performance of these new coatings.