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DS: Dünne Schichten
DS 7: Mechanical properties of thin films
DS 7.6: Vortrag
Montag, 27. März 2006, 17:15–17:30, GER 38
Cubic boron nitride coatings (c-BN) on cemented carbide cutting tools — •Ulrike Springborn1, Sung-Tae Park1, Eric Wiemann2, Kai Weigel1, Martin Keunecke1, and Klaus Bewilogua1 — 1Fraunhofer Institute for Surface Engineering and Thin Films, Bienroder Weg 54 E, D-38108 Braunschweig — 2Institute for Machine Tools and Factory Management, TU Berlin, Pascalstraße 8 - 9, D-10587 Berlin
Cubic boron nitride is the 2nd hardest of all known materials. In combination with other promising properties, like very high wear resistance, c-BN is a very attractive tool coating material. With a modified PVD sputter technique from a boron carbide target c-BN coatings with thicknesses over 1 µm could be deposited on pre-coated cemented carbide cutting inserts. After a first adhesion layer of a hard material, like TiN or TiAlN, a boron carbide layer is deposited. In the following B-C-N gradient layer deposition the c-BN nucleation takes place. The total coating thickness is in the range of 3 - 4 µm with a 1 to 2 µm thick c-BN top layer. The coating process and results from different mechanical and tribological characterisation methods will be presented in detail. The mechanical properties of the super hard, nano-crystalline c-BN coating systems with hardness above 60 GPa and Young’s modulus about 550 - 800 GPa are comparable with c-BN bulk material. The feasibility of c-BN coating systems as a super hard tool coating will be verified by results of cutting tests with coated cemented carbide cutting inserts.