ICMCTF2010 Session B2: Arc and E-Beam Coatings and Technologies

Wednesday, April 28, 2010 8:00 AM in Room Town & Country

Wednesday Morning

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8:00 AM B2-1 Arc Plasma Acceleration: A Method for Improving Coating Quality by Decreasing Macro Particle Inclusions
Viktor Khominich (Phygen Coatings, Inc.)
Macro particle inclusions are a major contributor to coating system failure in conventional PVD cathodic arc evaporation processes. Surface roughness produced by these inclusions can also require the use of expensive post coat finishing processes. Phygen Coatings has developed and patented an improvement to cathodic arc PVD coating technology that results in the reduction of the macro particles produced in comparison to conventional arc evaporation processes while maintaining comparable deposition rates. The Arc Plasma Acceleration process results in smoother finishes and a denser non-columnar coating microstructure which leads to outstanding coating performance. Phygen's process allows for depositing a wide range of materials at deposition rates similar to conventional cathodic arc processes while improving properties and can eliminate the need for post coat finishing.
8:20 AM B2-2 The Electron Beam High Rate Deposition in Combination with Guided Arc Discharges - Present State and Actual Developments
Jens-Peter Heinß (FEP, Germany)

The different PVD methods have found a wide-spread distribution in many industrial applications in the past. The electron beam (EB) evaporation with axial type guns is especially useable for depositions with a very high material throughput. Under such conditions EB-evaporation becomes economical and very attractive in comparison with other coating technologies.

We demonstrate the technical base for the large area and high productive electron beam evaporation. In special configurations it was realized to deposit a wide variety of alloys and compounds.

The plasma activation of the metal vapor and of the working gas gives further possibilities to control the layer growth and so the layer properties. We combined the EB evaporation with arc discharges so that the high arc discharge current density corresponds with the high rates of the EB-evaporation. We demonstrate the needed technical equipment for it and characterize a few plasma parameters. Whereas the first industrial applications were focused on the corrosion protection nowadays a couple of applications in modern technologies are under development. We present results of oxidic and carbon containing hard coatings and of electrical conducting layers for solar cells, which were deposited by using the plasma activated electron beam high-rate deposition.

9:00 AM B2-4 Structure and Mechanical Properties of Single- and Multilayer Hard TiAlN/TiAlYN-based Coatings, Produced by Reactive Cathodic-Arc Evaporation
Volodymyr Goltvyanytsya, Sergiy Goltvyanytsya (Real Ltd., Ukraine); Anatolii Demchyshyn, Leonid Kulak (Institute of Problems in Material Science, NANU, Ukraine)

The main reason of emergency and development of protective coatings was a purpose to increase details and components life. Production of optimal coatings provides for selection of necessary composition of coating, its structure, porosity and adhesion taking into account technological parameters of deposition process.

Hard coatings like TiAlN considerably enhance performance of tools or product, which are coated. It allows to increase working temperature and hardness of coatings. Moreover, using PVD-technology it is possible to develop multilayer composition coatings with nano thickness of each layer on the basis of refractory metal compounds. By varying of technological parameters of coating condensation it is possible to influence on their properties.

Multilayer combined deposits with alternate layers ensure optimal combination of wearability, strength and fracture strength.

Single- and multilayer systems were produced via vacuum-arc atomization of Ti-Al, Ti-Al-Y, Al-Ti cathodes in nitrogen atmosphere with further coatings condensation on steel substrates. Singlelayer coatings TiAlN with thickness 5-8 μm had microhardness Hμ=35-40 GPa. For creation of system with different layer thickness the time of one layer deposition varied from 10 to 30 sec. Total deposition time of coatings was the same and equal to 30-60 min. Thickness of sublayers was less than 100 nm. Microstructure, elemental and phase composition were studied by means of scanning microscopy, Auger-electron spectroscopy, X-ray microanalysis and X-ray structure analysis. Microhardness of vacuum-arc condensates was measured by means of systems PMT-3M and “Micron-Gamma”.

In this study influence of sublayers on structure properties of multilayer deposits TiAlN/TiAlYN (150-300 layers) with fixed total thickness 10-15 µm was examined.

Formed multilayer TiAlN/TiAlYN deposits had enhanced hardness and oxidation resistance in comparison with monolayer TiAlN owing to creation of protection amorphous Al2O3-Y2O3 layer, which prevented their further oxidation was established.

Improved mechanical properties of multilayer coatings in comparison with homogeneous deposits, which were formed on the basis of mononotrides of transition metals, can be widely adopted as protective heat resistant and anti-wear coatings.
9:20 AM B2-5 Microstructure Evolution of Ti3SiC2 MAX Phase Cathodes During Reactive Cathodic Arc Evaporation
Jianqiang Zhu, Anders Eriksson, Naureen Ghafoor (Linköping University, Sweden); Mats Johansson (SECO Tools AB, Sweden); Johanna Rosen, Lars Hultman, Magnus Odén (Linköping University, Sweden)

The Ti-Si-C-N quaternary system is a promising candidate for wear resistant coatings due to its good mechanical and thermal properties. MAX phase Ti3SiC2, due to its unique combination of mechanical, electrical and thermal properties, could potentially yield an attractive cathode material for reactive cathodic arc evaporation synthesis of Ti-Si-C-N coatings. The evolution of the surface microstructure and composition of sintered Ti3SiC2 cathodes during reactive cathodic arc evaporation in a pure N2 atmosphere and non-reactive cathodic arc evaporation in an Ar atmosphere with the arc current of 50 A is presented here. The results show that the cathodic arcing induces a converted layer on the cathode surface, in a form of overlapping craters with a diameter of 3-100 μm. The craters are shallow bowl-shaped pits with a raised outer rim, regardless of an Ar or N2 atmosphere. The microstructure and composition of the converted layer differs from the virgin Ti3SiC2 and it contains different features depending on the evaporation conditions. The virgin cathode consists of approximately 12 μm Ti3SiC2 grains mixed with a small amount of TiC grains of similar size. Under reactive N2 atmosphere conditions, the converted layer is 3-10 μm thick and consists of 100-500 nm TiC and TiN grains surrounded by a matrix that is rich in Si. Minor amounts of nanosize Ti3SiC2 grains also exist in this layer. In the non-reactive case, the converted layer is 10-40 μm thick and contains comparable amounts of 200-700 nm large TiC and Ti3SiC2 grains in a Si rich matrix. The surface roughness Ra-value of the worn cathodes increases from 2.4 μm to 6.2 μm when N2 is introduced in the deposition chamber.

9:40 AM B2-6 Influence of Process Parameters on Structure of TiAlN Coating Prepared by a System With Rotary Arc Cathodes
Petr Vogl (PIVOT a.s., Czech Republic); Mojmir Jilek Jr. (SHM, s.r.o., Czech Republic)

It is advantageous to have a tool for a coating stoichiometry calculation to control coating deposition made from two different cathodes. Stoichiometry depends not only on arc currents ratio, but also on intensity and shape of magnetic field. This relation has been experimentally verified and is presented for TiAlN coating prepared by a new coating device Pi111. With the aid of this tool, it is possible to estimate coating parameters and to reach the desired Al/Ti ratio in a coating.

With increasing content of Al in a coating, cubic structure shifts to hexagonal structure. This change proves itself not only by hardness decrease, but also by a change of coating growth rate. For detailed description of this effect, method of calculation of coating stoichiometry described above was used.

10:00 AM B2-7 Optimization of Micro Arc Oxidation Processes for Corrosion Resistance of Ti6Al4Valloys by Using Taguchi Method
Ebruemine Demirci, Ersin Aslan, Yasar Totik, Ihsan Efeoglu (Atatürk University, Turkey)

Micro Arc Oxidation (MAO) is a novel technique used to improve surface properties of Ti6Al4V alloys. A number of studies have been carried out for producing a corrosion resistant coating on Ti6Al4V alloys by micro arc oxidation processes. However, there are very few studies on the optimization of the MAO process parameters for corrosion resistance of Ti6Al4V alloys. In this study, Taguchi experimental analysis method was used to systematically investigate the effects of four parameters (deposition time, frequency, current density, and concentration of electrolyte) with three levels on the corrosion resistance of coatings. Potentiodynamic polarization measurements were conducted to determine the corrosion resistance of the samples. The percentage contribution of each factor was determined by the ANOVA. The optimum coating parameters that affected the corrosion resistance were determined by using Taguchi method. The results showed that which parametre was the most significant factor affecting on the coatings’s corossion resistance.

10:20 AM B2-8 Phase Formation of Alumina Thin Films Deposited by Ionized PVD
Kostas Sarakinos, Denis Music (RWTH Aachen University, Germany); Farwah Nahif (University of Cyprus); Kaiyun Jiang, Alexander Braun, Conrad Zilkens, Jochen M. Schneider (RWTH Aachen University, Germany)

Al2O3 films are deposited employing a monoenergetic Al+ beam generated by a flitered cathodic arc [1]. A critical Al+ ion energy of 40 eV for the formation of the α-Al2O3 phase at a substrate temperature of 720°C is determined. This energy is used as input for classical molecular dynamics and Monte-Carlo based simulations of the growth process, as well as ab initio calculations. The combination of theory and experiment indicates that in addition to surface diffusion the previously not considered diffusion in sub-surface regions appears to be an important atomistic mechanism for the phase formation of α-Al2O3.

[1] A. Atiser, S. Mraz, and J. M. Schneider, J. Phys. D: Appl. Phys. 42, 015202 (2009).

10:40 AM B2-9 Processing With Pulsed Plasmas: A Comparison of Cathodic Arcs and High Power Impulse Magnetron Sputtering
Andre Anders (Lawrence Berkeley National Laboratory)

Deposition by high power impulse magnetron sputtering (HIPIMS) is emerging as the new paradigm for metal ion etching and self-ion-assisted deposition. While HIPIMS has indeed many advantages, some features are re-invented in light of the already forgotten accomplishments with arcs, and especially filtered arcs and pulsed arcs. Therefore, it seems appropriate to present a comparative study highlighting the common features and as well as the distinct differences, both in terms of plasma parameters and film properties.

This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

11:20 AM B2-11 Evaluation of Residual Stress and Coating Composition on Rounded Surfaces and Edges by Measurements and Cutting Tests
Johan Bohlmark, Helen Blomqvist, Mats Ahlgren (Sandvik Tooling Sverige AB, Sweden)
Throughout the last decades various PVD technologies have grown to become large volume production methods for tool coaters. Today, the two most common PVD techniques are arc evaporation and magnetron sputtering. Both techniques are plasma based, and with that follow some typical features that in the end affect the coating performance. One typical feature of a plasma is the formation of a sheath region around the object to be coated. The formation of the sheath has some implications on the coating of three dimensional objects, since rounded surfaces and edges are subjected to different ion flux density. For example, it is well known that the coating often grows thicker on an edge than on a flat surface. Other differences may be observed in the coating composition and residual stress. Many publications reports data recorded on flat surfaces, but in real cutting applications the critical point is often close to an edge or curved surface. This paper presents measurements of the coating composition by EDS and residual stress with X-ray diffraction in coatings produced by arc evaporation on rounded surfaces and edges. It is observed that the coating composition changes with curvature. The concentration of materials that are more likely to be ionized in the plasma, such as Ti, is higher on objects with a high curvature. For example, the Ti content is about 10 % higher on a 1 mm diameter drill compared to an 18 mm drill. The residual stress in the coating is measured, and shows higher residual stress on and near the cutting edge as compared to a flat surface. The measurements also show that the residual stress in the coating is more dependent on the measurement location than the bias voltage. In addition, the observations are also correlated to metal cutting tests.
11:40 AM B2-12 Highly Transparent and Conductive ZnO:Al Thin Films Prepared by Laser Induced High Current Pulsed Arc at Low Deposition Temperature
Jin-Bao Wu, Chao-Ying Chen, Jia-Jen Chang, Chin-Te Shih, Ming-Sheng Leu (Industrial Technology Research Institute, Taiwan)

Highly transparent conductive Al-doped ZnO (AZO) thin film were deposited at 100℃ by laser induced high current pulsed arc (LIHCPA) from a Al-Zn alloy target. A pulsed current more than 1 kA was generated on the Al-Zn target in order to make highly ion energy and fully ionization plasma. The films properties were correlated with the growth conditions, including O2 flow rate, pulsed arc current apply to the target and Al doping content. The microstructure properties of the films such as surface morphology, crystallinity and chemical composition were studies using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrical and transmittance of the AZO films were investigated by the Hall measurement and UV/VIS spectrometer. The experimental XRD results show that the AZO films has preferred c-axis orientation along the (002) plane. The minimum resistivity is as low as 4.2×10-4 Ω-cm with the carrier concentration of 7.3× 1020 cm-3 and Hall mobility of 20 cm2V-1s-1 and the average transmittance of films in the visible range (400-700 nm) is above 84 %. It was found that the O2 flow rate affected not only the electrical properties of the films but also the band gap. The results clearly showed that when the O2 flow rate increased from 30 sccm to 150 sccm, the resistivity increased from 4.2×10-4 to 3.7 ×10-3 Ω-cm, and also the band gap of the AZO films calculated by UV/VIS spectrometer measurement would decrease from 3.76 eV to 3.58 eV.

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