ICMCTF1998 Session B1-4: Hard Coatings - Hybrid PVD Techniques on Coatings

Thursday, April 30, 1998 1:30 PM in Room Golden West

Thursday Afternoon

Start	Invited?	Item
1:30 PM	Invited	B1-4-1 Hybrid Processes - A Versatile Technique to Match Process Requirements and Coating Needs J.P. Celis, D. Drees, M.Z. Huq (Katholieke Universiteit Leuven, Belgium) The properties of thin hard coatings and consequently their functionality are influenced by the microstructural characteristics, such as phase composition and grain size distribution. Recent studies indicate that microlaminated hybrid-coatings offer an opportunity to establish uinque and controllable microstrucutral characteristics. A variety of interlayers has been used in hybrid coatings for various purposes: (I) to enhance the adherence between coatings and substrates, (ii) to prevent crack initiation, (iii) to give good shock resistance, (iv) to enhance corrosion protection of coating and substrate, and, (vii) to enhance sliding wear resistance or lower sliding friction. In order to obtain the above mentioned properties, various deposition techniques such as (1) electrodeposition, (2) ion-plating, (3) ion implantation, and, (4) magnetron sputtering can be used to prepare monolayered and multilayered hybrid-coatings. This review paper includes a discussion on deposition techniques and properties of different hybrid-coatings.
2:10 PM		B1-4-3 Graded TiAlN/Al₂O₃ and (Ti,Al)O-N CoatingsDeposited by High Ion Sputtering (H.I.S.^TM) PVD-process Technique G. Erkens, T. Leyendecker, R. Wenke, H.-G. Fuss, St. Esser (CemeCon GmbH, Germany); I. Rass, M. Feldhege (Euromat GmbH, Germany) The advantages of (Ti,Al)N based hard coatings in view of wear resistance and dry cutting are thoroughly investigated. The remarkable features like high hardness high oxidation resistance and high thermal stability are due to the formation of an Al₂O₃ top layer. These properties lead to best suitability for high performance operation. An adapted preparation combined with the new H.I.S^TM (High Ion Sputtering) PVD-process technique improves the performance of coated cutting tools. For ternary coating systems based on (Ti,Al)N a further improvement can be achieved by increasing the amount of Al₂O₃ or by sputtering reactively oxygenous interlayers. The increased power and current density of the High Ion Sputtering (H.I.S.^TM) PVD system module leads to a high rate of ionized material transmitted to the substrates. Due to this modification dense and fine grained structured films, typical of PVD processes with a high portion of ionized material, with a „dimpled surface" grow on the substrates even when the surfaces were micro blasted or ground before. In contrast to CVD Al₂O₃ containing films this process avoids embrittlement of cemented carbide tools and crack formation due to thermal mismatch. The maximum temperature during the deposition of graded TiAlN/ Al₂O₃ and (Ti,Al)O-N is 450°C. Therefore even the coating of HSS tools is possible. The deposited coatings were evaluated by metallographical examinations (microhardness, film thickness, adhesion, SEM etc.) and cutting performance tests. The illustrated results will show the potential of the H.I.S.^TM process technique and the new developed PVD coating.
2:30 PM		B1-4-4 Mechanical and Electrical Properties of FCC TiO_1+x Thin Films Prepared by RF Reactive Sputtering A.R. Bally, P. Hones, R. Sanjines, P.E. Schmid, F. Levy (Swiss Federal Institute of Technology of Lausanne, Switzerland) This paper reports on an investigation on fcc TiO_1+x thin films with x ~ 0.2. The films were deposited by RF reactive sputtering at different temperatures (300K-600K) and characterized by X-ray diffraction, electron probe microanalysis, X-ray photoelectron spectroscopy, scanning electronic microscopy, atomic force microscopy, scanning transmission microscopy, and electrical measurements. The films crystallize in the fcc phase with a lattice parameter a = 0.419 nm, exhibit a gold like color, an electrical resistivity of about 500 μΩcm at room-temperature, and remarkable nanohardness values of about 23 GPa. The results of these experiments are discussed and compared to the archetypal fcc TiN coatings.
2:50 PM		B1-4-5 PVD Hard Coatings for High Speed Dry Cutting of Hard Materials W. Fleischer, M. Franck (Hauzer Coating Centrum BV, The Netherlands); G.J. Van der Kolk, T. Hurkmans (Hauzer Techno Coating Europe BV, The Netherlands); H. Kunen (Jabro Tools, The Netherlands) High speed cutting with spindle speeds of more than 10.000 rpm is a trend for cutting technologies in many important fields, especially for milling operations. The required coating on cemented carbide endmills for such a kind of application was optimized as a multilayer system based on TiAlCn and TiN. The test results in hardened steel with 55 to 60 HRC will be described.
3:10 PM		B1-4-6 Coatings in the Chromium-Carbon System. J. Hampshire, J. Witts, K. Laing, D.G Teer, G. Dyson (Teer Coatings Ltd, United Kingdom) Coatings of Chromium-Carbon ranging from 0 to 90% carbon have been deposited by Closed Field Magnetron Sputter Ion Plating [1].The structure and properties of the coatings have been studied. The coatings are found to have an extremely dense structure which does not appear to conform to the usual structure zone modes [2,3]. Totally dense coatings of thickness up to 30micrometers can be deposited. The hardness, adhesion and tribological properties of the coatings are studied and presented. The coatings are highly wear resistant and appear to be useful in a wide range of applications from artificial hip joints to automobile engine parts. References [1] D G Teer, UK Patent 225843A. [2] Thornton, J A. Influence of substrate temperature and deposition rate on the structure of thick sputtered copper coatings. J. Vac. Sci. Technol. Vol 12, 1975, 830-835. [3] Messier, R. Giri, A P. Roy, R A. J. Vac.
3:30 PM	Invited	B1-4-7 Cratering Behavior in Single- and Poly-crystalline Copper Irradiated by an Intense Pulsed Ion Beam B.P. Wood (Los Alamos National Laboratory) Energetic ion bombardment is commonly used during deposition processes to densify and improve the adherence of hard, amorphous coatings. Preceding deposition by a very high energy ion implantation step can further increase adherence of the subsequently deposited coating by creating a functionally graded interface region, over which the material properties change smoothly from the substrate into the coating. This mixed interface may be very thin - only 20 nm in the case of heavy metal-oxide ceramics on steel - and still greatly improve coating adherence. Since this is a non-equilibrium process which can be performed cold, it allows treatment of aluminum and heat sensitive alloys of steel which would be damaged by conventional thermal treatment. In this talk, methods of producing this functionally graded interface with intense ion beam and plasma source ion implantation processes will be described, along with specific results for erbium oxide on steel and diamond-like carbon on a variety of substrates. The equipment needed for this process will be examined, and Los Alamos National Lab collaborations with industry (through the NIST Advanced Technology Program) to produce such equipment and make it commercially available will be described.
4:10 PM		B1-4-9 High Purity Nano-crystalline Carbon Nitride Films Prepared at Ambient Temperature by Ion Beam Deposition Z.L. Yang (Academia Sinica, Taiwan); L.C. Chen (National Taiwan University, Taiwan); K.H. Chen (Academia Sinica, Taiwan); T.-M. Chen, C.-T. Kuo (National Chiao Tung University, Taiwan) High purity nano-crystalline carbon nitride films with high£]-C₃N₄ concentration are successfully prepared by ion beam deposition using a novel bio-molecular C-N containing target material consisting of covalently C-N bonding , high N/C ratio and six membered ring structure similar to that in hypothetical C₃N₄, instead of the conventional graphite without nitrogen . The films can be deposited on various substrates such as copper, silver, stainless steel, nickel and silicon wafer at ambient temperature. Scanning Auger microscopy (SAM) indicates a high nitrogen to carbon ratio of 0.56. The chemical bonding structure as revealed by Infrared spectroscopy and Auger spectroscopy consists of sp3 hybridization of the carbon and sp2 hybridization of the nitrogen and carbon. Both Transimision electron microscopy (TEM) and SAM mapping studies indicate the average grain size to be about 3nm, with a very dense and homogenous distribution of nano-crystalline grains with trace of amorphous phase in the film, unlike the commonly observed films with C-N crystallites embedded in amorphous carbon matrix. TEM diffraction patterns from these crystals match well with the calculated pattern for£]-C₃N₄. Further elevation of the substrate temperature in this process is expected to afford in increasing degree of grain growth in the carbon nitride grains.
4:30 PM		B1-4-10 Effects of Ionization Power to Ion Energy Distribution in Ionized Sputtering Measured by an Energy-resolved Mass Spectrometer E. Kusano, N. Kashiwagi, T. Kobayashi, H. Nanto, A. Kinbara (Kanazawa Institute of Technology, Japan) An ionized magnetron sputtering technique improves film properties by ionizing and energizing sputtered particles in the region between the sputtering cathode and the substrate by using an inductively coupled rf plasma generated by a coil located in front of the sputtering cathode. In addition, directionality of the sputtered particles can be controlled by applying a substrate bias, as a result of high ionization. In this technique, it is crucial to give a proper energy to the particles to prevent disorder or other undesired damages to the film. In this study, energy distribution of particles has been measured by an energy-resolved mass spectrometer for Ti non-reactive and Ti-N₂ reactive sputtering to discuss effects of relation between rf coil power and cathode power to ion energies. The cathode used in the experiment was a 55mm dia. magnetron type with a Ti target, equipped in an ultra-high vacuum apparatus. Ion energy was measured by PPM-421 Plasma Monitor(Balzers) whose orifice to the ion analysis optics was set in front of the sputtering cathode with a distance of 200mm. The rf coil power was changed up to 200W. The cathode power was changed from 50W to 200W for the rf mode and from 20W to 90W for the dc mode. The experimental results show that energy of sputtered Ti particles was enhanced from a few eV to about 30eV in dc sputtering and from a few ten eV to more than 100eV in rf sputtering, by increasing an rf coil power. The energy increase by ionization and energization by an rf plasma was more drastic for a lower cathode power in both dc and rf sputtering. Energy distribution of Ar⁺ was also observed to shift to a higher energy as an rf plasma power increased. In Ti-N₂ reactive sputtering, N₂ particles were also ionized and energized to more than 50eV for both dc and rf sputtering. It was further found that the orientation of the Ti and TiN films was affected by energization of particles.