ICMCTF2003 Session G1/TS1: Innovations in Surface Coatings and Treatments
Wednesday, April 30, 2003 1:30 PM in Sunrise
G1/TS1-1 New Microwave and Hollow Cathode Hybrid Plasma Sources
L. Bardos, H. Baránková (Uppsala University, Sweden)
New hybrid plasma sources for both low gas pressure processing (<10@super -2@ mbar) and for generation of cold atmospheric plasma were designed, developed and tested, [1,2]. The sources combine advantages of the microwave plasma with the hollow cathode plasma in a common system. The low-pressure hybrid plasma source (HYP LP) combines the ECR (Electron Cyclotron Resonance) plasma inside microwave radiator and the radio frequency (RF) hollow cathode plasma generated by linear magnetized hollow cathode at the outlet of the radiator. The plasmas are coupled together in a common magnetic field facilitating both the hollow cathode plasma and the ECR absorption of the microwave power in the vicinity of the cathode outlet. The plasma density measured 15 cm below the source outlet at 1 kW incident power from both generators reaches 5 x 10@super 11@ cm@super -3@ at argon pressures of the order of 10@super -3@ mbar. This classifies the HYP LP source as a high-density plasma source. The plasma density in the reactor chamber is very uniform which is important for large-area processing applications. The TiN film deposition rate of about 150 nm/min was achieved in the reactive PVD of highly (111) textured TiN films at gas pressure of 7 x 10@super -3@ mbar. Operation principles of the HYP LP sources open an exciting opportunity for future developments of non-conventional composite coatings and for coating property engineering. The atmospheric pressure hybrid plasma source (HYP AP) combines a microwave antenna and a RF hollow cathode in a common electrode. The source is able to produce atmospheric plasma plumes and to control plasma parameters efficiently. The HYP sources have a full ambition to become new processing tools on the market, suitable either for new systems or for upgrade of existing systems. @paragraph@ L. Bardos and H. Barankova, Swedish patent 9904295-4, PCT/SE00/02315. @paragraph@ EU Project "HYBRID", Nr. GRDI-1999-10393.
G1/TS1-3 High Vacuum Applications of Silicon-based Coatings on Stainless Steel
D.A. Smith (Restek Corporation); B.R.F. Kendall (Elvac Laboratories)
Tests of stainless steel components passivated with a silicon-based coating showed unexpectedly low rates of gas evolution. Progressive improvements to the coating process have led to significantly lower outgassing rates over a wide range of operating conditions when compared with untreated stainless steel. Special techniques have been developed for comparing otherwise identical samples having various surface treatments and/or coating types. The samples are heated and cooled in turn while the outgassing rates are recorded at temperatures up to 250@super o@C. Base pressures ranged from 10@super -7@ Torr to 2.5 x 10@super -10@ Torr. The coatings are resilient, inert and capable of withstanding temperatures above 400@super o@C. As well as their obvious potential for reducing outgassing rates in vacuum chambers thereby allowing shorter pump-down times with smaller vacuum pump systems, they have proved useful in minimizing errors due to thermal desorption in experimental metal-envelope ionization gauges operating down to the low 10@super -10@ Torr range.
G1/TS1-4 The Influence of Coating Mechanical Properties at Various Film Thicknesses on the Milling Performance of PVD Cemented Carbide Coated Inserts
K.-D. Bouzakis, S. Hadjiyiannis, G. Skordaris, K. Efstathiou, I. Anastopoulos, I. Mirisidis, N. Michailidis (Aristoteles University of Thessaloniki, Greece); G. Erkens, R. Cremer (CemeCon AG, Germany); S. Rambadt, I. Witrh (CemeCon GmbH, Germany)
The film deposition conditions on individual specimens located in various positions in the vacuum chamber during a PVD coating procedure, with constant power law, can not be considered as identical. Depending on the applied deposition parameters, such as the magnetic field distribution in the vacuum chamber, the specimen fixture geometry and its kinematics etc, the occurring coating crystalline structure and thus the hardness and the mechanical properties might vary. @paragraph@ In order to investigate the effect of coating hardness and strength properties deviations on the cutting performance, occurring due to the aforementioned peculiarities during a PVD process, (Ti@sub 46@Al@sub 54@)N films with thicknesses from 2 up to 10 µm were deposited on cemented carbide inserts in individual PVD processes. The obtained coating material properties and especially their stress strain laws, were determined by means of a FEM-based evaluation procedure of nanohardness measurement results. Moreover milling experiments to investigate the effect of the mechanical properties variations on the cutting performance in the examined coating thickness cases were conducted. The initiation and progress of the tool failure was depicted through Scanning Electron Microscopy (SEM) observations and Energy Dispersive X-ray microspectral analyses of the used cutting edges. @paragraph@ The investigations showed that an increasing of the coating thickness diminishes the superficial coating strength, however leads to a cutting performance enhancement. The numerically extracted results based on a FEM simulation of the milling process, explain the achieved cutting performances at various coating hardnesses and thicknesses. @paragraph@ Furthermore the obtained results illustrate that the coated tool cutting performance is less affected by potential coating mechanical properties deviations in the case of thick coatings, in comparison to thinner ones, where corresponding differences in coating mechanical properties significantly deteriorate the cutting performance.
G1/TS1-5 Investigation Into the Properties of Dielectric Films Deposited using Pulsed Magnetron Sputtering
P.S. Henderson, P.J. Kelly, R. D. Arnell (University of Salford, United Kingdom); J.W. Bradley, H. Baecker (UMIST, United Kingdom)
Pulsed magnetron sputtering is widely used for the deposition of metal oxide films due to the inherent problems of the oxides being insulators. The pulsed power suppresses arcs and leads to improvements in deposition conditions. This study details the effects of pulsed power on the film properties of both aluminium oxide and titanium dioxide. The films were deposited by using asymmetric bi-polar pulsed sputtering on a variety of substrates to allow for numerous analysis techniques. Both the pulse frequency and duty factor were systematically varied in the ranges 0-350kHz and 50-100% respectively for both materials. Analysis was carried out in terms of optical properties, microstructure, crystalline structure, scratch adhesion, wear resilience and hardness. Variations were seen in both materials properties with the use of pulsed sputtering over that of DC sputtering. Differences were also noticed with the variation of pulse frequency and duty factor. The results were related to the plasma parameters during the deposition process. All the findings are reported here.
G1/TS1-6 Implementation of a Pulsed Sputtering Process into an Industrial Batch Coating System and its Application to the Development of Novel Oxide and Nitride Coatings
R. Cremer, G. Erkens, W. May (CemeCon AG, Germany); T. Linz, M. Lutz (Advanced Energy Industries GmbH, Germany); D.J. Christie (Advanced Energy Industries, Inc.)
Although well known in web coating and large area coating, only limited information is available about the usage of pulsed power supplies in industrial batch coating systems. Nevertheless, the ever increasing demands on modern cutting tools result in the need of novel approaches in the development of advanced hard coatings and its deposition technology. Thus, pulsed DC and low-frequency plasma sources are gaining increasing attention. In this paper, we report about the implementation of this technology into modern batch coating systems by a joint effort. The suitability of pulsed magnetron sputtering for the deposition of advanced hard coatings will be illustrated. We will report on the development of the novel High Ionization Pulsing (H.I.P.@superTM@) process as well as on the tailor made design of pulsed power supplies for the deposition of hard coatings. The effectiveness of this approach will be illustrated by two examples. In addition to the deposition of alumina, the potential of different novel supernitrides with outstanding cutting performance will be presented.
G1/TS1-7 Design Considerations for a High Efficiency Ion Beam System for IAD Applications
W.G. Sainty (Sain Tech Pty Ltd., Australia)
Most commercial ion sources available today provide for a continuous or steady flux of ion beam current. For stable operation, these sources generally require a static, stable and, in some cases, controlled vacuum environment. In a real vacuum deposition system, this is not always possible to achieve and can result in unstable behaviour. This problem is usually related to changes occurring in the load (the ion source) that is presented to the power supply. @paragraph@ At Saintech we have been exploring ways to reduce this problem by, effectively, de-coupling the power supply from the ion beam system. There are several ways of achieving this and we have been exploring two such techniques. So far we have been successful in operating the ion source in a pulsed mode where the pulsing is achieved by electronically opening and closing a valve to admit small quantities of process gas. The pulse frequency and duration are independently controllable. Feeding the gas pulses from a constant pressure manifold controls the energy in the pulses. The pulse energy can be as high as several amps at ion energies of 200 eV. The duty cycle can be as much as 10:1 (ON pulse 1000 msec : OFF 100 msec) to 1:250 (ON 100 msec : one pulse every 25 seconds). The former parameters have application to IAD of most metal oxide materials while the latter parameters have application to the IAD of many IR and UV film depositions.@paragraph@ There are many advantages resulting from this mode of operation: 1)Highly stable and reliable operation. 2) Lower average gas flow without sacrificing average energy. 3) Extended filament life. 4) More compatible with the operation of thermal and electron beam evaporators. 5) Easily interfaced with process controllers. 6) The IAD of many film stacks can be carried out at very low pressures because the average gas flow can be as low as 1 sccm of process gas.
G1/TS1-8 Characteristics of Saw Cutting Edges for Advanced Coating Technologies
M. Sarwar (Northumbria University, United Kingdom); F. Löffler (Physikalisch-Technische Bundesanstalt, Germany)
New and modern coating technologies have great potential to improve and, or enhance the life of cutting tools. The surface conditions or characteristics of the tool surface and cutting edge to provide better wear resistance and hence improvement in tool life, is governed by having a good knowledge of the tool geometry, especially the condition of the cutting edges and of the surface characteristics. The performance and failure modes in multi-point cutting tools such as circular saws and band saws are more complex than those in single point tools. Consequently the coating possibilities, requirements and limitations for multi-point tools are different to single point tools.@paragraph@ The paper characterises the cutting tool geometry and the surface properties of industrial saws. Surface requirements and tool preparations, which are necessary for wear resistant coatings, are described. Suitable advanced coating processes are shown and the performance of the coated tools determined through cutting tests and metallographic analysis are presented.@paragraph@ The paper should be of interest to the materials engineer, surface coater, cutting tool designer and manufacturer.
G1/TS1-9 A Study on the Factory Affecting the Structure of the Layer Implanted by Metal Plasma Based Ion Implantation using a UBM Cathode
L. Xia, Z. Yan, W. Yu (Harbin Institute of Technology, PR China); Z. Zhang (Harbin University of Sciences and Technology, PR China)
The effects of the processes parameters on the structure of the AgMgNi-alloy implanted by Cu, Al and Mo plasma based ion implantation (PBII) using unbalanced magnetron sputtering (UBM) were investigated. The results showed that when the metal plasma generated by unbalance magnetron sputtering (UBMS) and radio frequency, the structure of the implanting layer is depended on following parameters. They are: the sputtering currents for the magnetron targets, the distance from the substrate to the magnetron target, the high voltage pulse applied to the substrate and the implanting metal element etc. If the sputtering current is low and the distance from the substrate to target is long, only the implanted layer exhibits, but the depth profile in the layer is not a Gausses curve (which can be found in the gaseous ion implanted layer), while the content of implanted metal elements is from high value at surface gradually decreased to a certain value at the deeper zone and near to the primary composition of the substrate. If the sputtering current of UBM is enough high and the distance between substrate to target is less than certain value, a deposited layer was presented on the surface of substrate beside implanted layer such as mention above. The composition and microstructure from deposited layer to implanted layer changed gradually. For three different metal elements Cu, Al and Mo, under same implantation condition, the implanted depth of Al is deeper than Cu and Mo.