Multi c-BN Coatings by r.f Diode Sputtering and Investigation of Wear Behavior.

Cubic boron nitride (c-BN) films on tool substrates are tendency to delaminate. Therefore, many research groups have studied improvement of c-BN synthesis method and deposition processes due to many potential applications. In this paper, we show that the adhesion property of c-BN layer system can be improved by deposing multi c-BN layers. The multi c-BN layers were deposited by r.f (13.56 MHz) diode sputtering apparatus on cemented carbide tool substrates with a TiAlN adhesion layer. For industrial applications, we performed turning and milling experiments under dry and high speed cutting conditions. In this multi c-BN layer system, the lifetime of the tool is affected by the physical properties of the substrate and coated layers such as substrate grain size, thickness of the TiAlN and first c-BN layer and the total number of c-BN layers in this system. Mostly, fine grain size substrates showed longer lifetimes of over 4 times than raw one. In the turning performance, mono TiAlN layer systems were about two times lower lifetime than mono and multi c-BN layer system, moreover, we could be improved adhesion property for milling performance on tool substrates with binary multi c-BN layer systems under dry and high speed cutting conditions. The new application results of the multi c-BN layer system confirm that the high potential of c-BN coatings on cutting tools.