PVD Method Research Articles

The influence of Kanthal wire surface defects on the formation of Si nanolayer deposited by PVD method

Abstract The subject of this research is the structure of a Si nanolayer deposited on a FeCrAl wire surface by means of magnetron sputtering method. Si layer was selected as one of possible protections of the wire surface against excessive corrosive-erosive wear. In order to increase the power necessary for the DC discharge of the magnetron with Si cathode, a second magnetron with an aluminum disc as a cathode was used. The wire was attached to a carousel holder to ensure its rotation around the magnetron. The thickness of the deposited layers was about 150 nm. A wire surface examination indicated the presence of defects such as gaps between grains, cavities as well as severely deformed grains of surface layer. The research was conducted on the sample sections which had been prepared by focused ion beam method (FIB). The technique of transmission microscopy, which was used for observation, allowed us to obtain images in bright field (BF), dark field (DF), as well as in high resolution (HREM). The studies were also performed on the wire surface after the cutting process of the expanded polystyrene blocks. A metallographic optical microscope Nikon MA200 with a large depth of field was used for the examination which showed the presence of carbon deposit products. Additionally, a composition microanalysis was carried out along the line within selected areas of samples, with the use of energy dispersive spectroscopy (EDS). A large impact of wire surface defects on Si layer forming was found as well as a high direct homogeneous growth. The examination of the sections indicated the existence of a mechanism of defects sealed by Si layer, where directionality of grains growth in these areas revealed the tendency for vertical location relative to defects surface. Consequently, closed nanopores, i.e. spaces not covered with Si layer, were created. It is a characteristic feature of areas with defects covered with an oxide film created in a natural way.

Formation of Ti/TiN Thin Films by PVD Method and Their Corrosion Resistance in Boric Acid

Formation of Ti/TiN Thin Films by PVD Method and Their Corrosion Resistance in Boric Acid

Evaluation of residual stress and adhesion of Ti and TiN PVD films by laser spallation technique

The laser spallation technique was applied for measurement of residual stress and adhesion of thin films. Two films of different properties, ductile and soft Ti, and hard and brittle TiN, were studied. The films were produced on 304 steel substrate by PVD method. The residual stress value obtained by laser spallation technique LST were compared with stress value from X-ray diffraction method. Good agreement of stress values measured by both methods was attained. Additionally, the interface strength of the films was tested by laser adhesion spallation technique LASAT with use of VISAR system. It was shown that shock wave induced by a nanosecond laser pulse adequately determines properties of PVD thin films on metal substrate.

Self-assembly of dodecaphenyl POSS thin films

The self-assembly abilities of Dodecaphenyl Polyhedral Oligomeric Silsesquioxane thin films on Si(1 0 0) surfaces were studied. Due to their thermal properties – relatively low sublimation temperature and preservation of molecular structure – cage type silsesquioxanes are ideal material for the preparation of a thin films by Physical Vapor Deposition. The Ultra-High Vacuum environment and the deposition precision of the PVD method enable the study of early stages of thin film growth and its molecular organization. X-ray Reflectivity and Atomic Force Microscopy measurements allow to pursuit size-effects in the structure of thin films with thickness ranges from less than a single molecular layer up to several tens of layers. Thermal treatment of the thin films triggered phase change: from a poorly ordered polycrystalline film into a well-ordered multilayer structure. Self-assembly of the layers is the effect of the π−stacking of phenyl rings, which force molecules to arrange in a superlattice, forming stacks of alternating organic-inorganic layers.

An efficient data hiding method based on adaptive directional pixel value differencing (ADPVD)

Steganography is an important secret information communication technology in which one may send messages without others having knowledge of their existence. This paper proposes a new adaptive steganography method for color images using adaptive directional pixel-value differencing (ADPVD). The proposed method increases the capacity of the hidden secret data and improves the security of the stego-color image as well. The hiding capacity of the original PVD method is investigated by considering three directional edges: horizontal, vertical and diagonal directions using color cover image. The cover image is partitioned into 2-pixel blocks in a non-overlapping fashion and scanned in raster-scan order in all three directions. The proposed method adaptively selects the appropriate embedding directions for each color channel according to the largest embedding capacity. The security is improved since different pixel directions are employed adaptively to embed different number of message bits in each color channel. The experimental results show that the proposed method provides both larger embedding capacity and better visual quality of the stego color image compared with other PVD-based algorithms.

The Effect of the Cutting Parameters on the Machined Surface Roughness

From the invention of turning machine or lathe, some engineers are trying to increase the turning productivity. The increase of productivity is following after the breakout in instrumental area, such as the hard alloy instrument and resistance to wear cutting surfaces. The potential of cutting speed has a certain limit. New steel marks and cutting surfaces types allow significantly increase cutting and turning speeds. For the most operation types the productivity increase begins from the feeding increase. But the increase of feeding goes together with machined surface result decreasement. Metal cutting with high feeding is one of the most actual problems in the increasing of manufacturing volume but there are some problems one of them is the cutting forces increasement and larger metal removal rate, which decrease the cutting tool life significantly. Increasing of manufacturing volume, going together with the cutting instrument technology and material evolution, such as the invention of the carbide cutting materials and wear resistant coatings such as TiC and Ti(C,N). Each of these coating have its own properties and functions in the metal cutting process. Together with this evolution the cutting tool geometry and machining parameters dependencies are researched. Traditionally for the decreasing the machining time of one part, the cutting parameters were increased, decreasing by this way the machining operation quantity. In our days the wear resistance of the cutting tools increasing and it is mostly used one or two machining operations (medium and fine finishing). The purpose of the topic is to represent the experimental results of the stainless steel turning process, using increased cutting speeds and feeding values, to develop advanced processing technology, using new modern coated cutting tools by CVD and PVD methods. After investigation of the machined surface roughness results, develop the mathematical model of the cutting process using higher values of the cutting parameters.

ADHESION OF BIOCOMPATIBLE TiNb COATING

Preparation of a coating with a high quality requires good adhesion of the film to the substrate. The paper deals with the adhesion of biocompatible TiNb coating with different base materials. Several materials such as titanium CP grade 2, titanium alloys Ti6Al4V and stainless steel AISI 316L were measured. Testing samples were made in the shape of small discs. Those samples were coated with a TiNb layer by using the PVD method (magnetron sputtering). Onto the measured layer of TiNb an assistant cylinder was stuck using a high strength epoxy adhesive E1100S. The sample with the assistant cylinder was fixed into a special fixture and the whole assembly underwent pull-off testing for adhesion. The main result of this experiment was determining the strength needed to peel the layer and morphology and size of the breakaway. As a result, we will be able to determine the best base material and conditions where the coating will be remain intact with the base material.

Cavitation erosion of CrN/CrCN multilayer coating

Results of investigations of multilayer CrN/CrCN coating – X6CrNiTi18-10 stainless steel substrate system exposed to cavitation degradation are presented. CrN/CrCN coating with six CrN + CrCN bilayers was deposited using cathodic arc evaporation PVD method. Cavitation erosion tests showed that deposition of CrN/CrCN coating increased incubation period, but cumulative mass loss of the CrN/CrCN – X6CrNiTi18-10 system was higher than that of the steel substrate one. Microscopic study revealed that the degradation process was dominated by fatigue. Austenitic steel fractured in a mixed mode with domination of a ductile mode, while the CrN/CrCN coating fractured mainly in a brittle mode. Degradation of the CrN/CrCN coating was accelerated by delamination that decreased coating toughness. A highly eroded zone of the coated specimen was of similar size to the steel specimen one, but the whole eroded area was much smaller. Performed investigation indicated that the CrN/CrCN coating is not resistant to high-velocity impacts of micro-jets. Other impacts caused coating undulation and removal of micro-droplets formed during coating deposition. The main reason of brittle fracture was high stiffness of the coating and high-velocity impacts of cavitation pulses.

Recent developments in turning hardened steels – A review

Hard materials ranging from HRC 45 – 68 such as hardened AISI H13, AISI 4340, AISI 52100, D2 STL, D3 STEEL Steel etc., need super hard tool materials to machine. Turning of these hard materials is termed as hard turning. Hard turning makes possible direct machining of the hard materials and also eliminates the lubricant requirement and thus favoring dry machining. Hard turning is a finish turning process and hence conventional grinding is not required. Development of the new advanced super hard tool materials such as ceramic inserts, Cubic Boron Nitride, Polycrystalline Cubic Boron Nitride etc. enabled the turning of these materials. PVD and CVD methods of coating have made easier the production of single and multi layered coated tool inserts. Coatings of TiN, TiAlN, TiC, Al2O3, AlCrN over cemented carbide inserts has lead to the machining of difficult to machine materials. Advancement in the process of hard machining paved way for better surface finish, long tool life, reduced tool wear, cutting force and cutting temperatures. Micro and Nano coated carbide inserts, nanocomposite coated PCBN inserts, micro and nano CBN coated carbide inserts and similar developments have made machining of hardened steels much easier and economical. In this paper, broad literature review on turning of hardened steels including optimizing process parameters, cooling requirements, different tool materials etc., are done.

Properties and Application of Protective Coatings Obtained by Plasma Spraying and PVD Methods

Properties and Application of Protective Coatings Obtained by Plasma Spraying and PVD Methods

Corrosion Studies of Nanostructured AlN Coating Deposited on 23/8N Nitronic Steel by PVD Method

The microstructure properties and degradation behavior of nanostructured Aluminium Nitride (AlN) coating deposited on 23/8N Nitronic steel by Physical Vapour Deposition Technique (PVD) subjected to oxidation in molten salt [Na2SO4-25NaCl] environment at 700 °C for 50 hours has been carried out in the present work. The morphologies and scale of the coatings were characterized by using Fe-Sem microscopy/ energy dispersive analysis. The coatings have uniform microstructure. It is evident from the microstructure that the coatings has some pores and inclusions. The coating thickness for as coated AlN coatings is 2µm±1µm. The average grain size of AlN coatings is 16 nm. The results obtained showed the better performance of AlN coated specimens as compare to bare substrate.

Methods of nanostructured coatings deposition by magnetron sputtering and cathodic arc evaporation

Nanoscale coatings improve hardness, corrosion resistance and wear resistance of the cutting tools and machine parts. The sputtering magnetrons and the cathodic arc evaporators are used in industrial and medical applications to produce functional and protective films. PVD methods of nanostructured coating deposition based on limitation of crystal growth are described in this article. Three methods are applied for this purpose. Metal cathodes containing 3%-12% additives such as Si, B, BN, Cu, Ni are used to limit the crystal growth in the nanoscale range. The substrate rotation leads to the reduction of the layer thickness to obtain the multilayer nanoscale coatings. Bias voltage applied to the substrate holder for the ion bombardment and the substrate heating can be used to reduce the crystal size in the coating. The design of the vacuum set with plasma sources and ion beam source is considered.

Methods of nanostructured coatings deposition by magnetron sputtering and cathodic arc evaporation

Nanoscale coatings improve hardness, corrosion resistance and wear resistance of the cutting tools and machine parts. The sputtering magnetrons and the cathodic arc evaporators are used in industrial and medical applications to produce functional and protective films. PVD methods of nanostructured coating deposition based on limitation of crystal growth are described in this article. Three methods are applied for this purpose. Metal cathodes containing 3%-12% additives such as Si, B, BN, Cu, Ni are used to limit the crystal growth in the nanoscale range. The substrate rotation leads to the reduction of the layer thickness to obtain the multilayer nanoscale coatings. Bias voltage applied to the substrate holder for the ion bombardment and the substrate heating can be used to reduce the crystal size in the coating. The design of the vacuum set with plasma sources and ion beam source is considered.

Morphology and Mechanical Properties of TiN Coatings Prepared with Different PVD Methods

Abstract TiN coatings were prepared on the GCr15 substrate by the cathode arc deposition, medium frequency magnetron sputtering and their composite methods. The coatings were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) spectroscopy, microscratch test, friction and wear test. Moreover, the effects of different preparation methods on the structure and mechanical properties of the coatings were compared. The results show that the coating prepared by the composite method of arc and magnetron possesses a smooth surface and better comprehensive properties such as high cohesion and hardness; thus the wear rate is lower

Fracture and deformation mechanism of Ti(C,N)/TiAlSiN multilayer coating: FE modeling and experiments

Ti(C,N)/TiAlSiN multilayer coating was deposited on GTD450 using the Cathodic Arc PVD method to protect compressor blades from erosion damage. The fracture and deformation mechanisms of coating were investigated. To better observe fracture and deformation events and thus the need to apply high loads, Vickers microhardness test was performed and imprint diagonals were measured. Then, using SEM analysis, indent surfaces were investigated to observe crack initiation and deformation patterns at different loadings. It was found that crack initiated at the coating top surface (top surface of TiAlSiN layer) at a loading range of 250–500mN. Cross-section SEM images of indent surfaces at lower loads revealed shear sliding and radial cracking below the indenter in the coating-substrate interface (bottom surface of Ti(C,N) layer). To better understand coating fracture and deformation, a 3D FE model was used to determine stress distribution in the coating. FEM results showed that maximum Von Mises stresses occur beneath the indenter and its edges, causing shear sliding to take place. Also, maximum principal stresses at lower loads take place beneath the indenter at the coating-substrate interface. As load increases, the maximum principal stress zone changes and is transferred to the coating top surface. Maximum principal stress was produced during the unloading process at the coating top surface or median plane and may cause lateral cracking. Experimental and FEM results were in good agreement.

Electrodeposition of Titanium in Water−Soluble KF−KCl Molten Salt

１． Introduction Metallic titanium has superior properties such as corrosion resistance, heat resistance, specific strength, etc. However, its high production cost and poor workability hinder the wide spread use of titanium. Coating technology is a fascinating method to utilize the characteristics of high corrosion resistance and high strength of titanium metal or compounds. Currently, PVD methods are commonly used for a coating of some titanium compounds, however, the deposition onto a substrate with complicated shape is difficult. Electroplating in molten salts has been expected as a coating method of titanium even for any shapes. Until now, there are some reports on the titanium electrodeposition from molten salts [1-7]. In previous studies, fluoride [3,6], chloride [1,2,4], and fluoride-chloride [4,5,7] molten salts have been used as electrolytes. Generally, compact and smooth Ti films were obtained from fluoride melts such as LiF–NaF–KF [3,6] or fluoride-chloride melts such as NaCl–KCl–NaF [5,7]. For the fluoride-chloride mixtures, when F/Cl atomic ratio became higher, better deposits (grain size and purity) were obtained and higher current efficiency were achieved [5,7]. However, one of the problems in the previous studies employing fluoride-based molten salts was the difficulty in removing the salt adhered to the deposited Ti, because the solubilities of LiF and NaF in water are very low. Recently, we have proposed a new electrodepositon process of Si using a KF–KCl binary system [8]. Since both KF and KCl are highly soluble in water, the adhered salt can be removed easily by washing with water. In the present study, we investigated the electrodeposition of Ti in molten KF–KCl after the addition of K2TiF6and sponge Ti. ２． Experimental The experiments were conducted in eutectic KF–KCl in a dry Ar atmosphere at 923 K. K2TiF6 (0.1-2.0 mol%) and Ti sponge (10 g) were added to the bath as Ti sources, and Ti (IV) ions were converted to Ti (III) ions by proportionation reaction. A Ni plate electrode was used as a working electrode. The counter and quasi-reference electrodes were a Ti rod and a Pt wire, respectively. The potential of the quasi-reference electrode was calibrated by the deposition potential of K metal on a Mo wire. Samples produced by the galvanostatic electrolysis were analyzed using SEM/EDX and XRD after washed with water to remove the adhered salts. ３． Result and discussion The samples preparation was carried out by galvanostatic electrolysis under the conditions of the added amount of K2TiF6 of 0.1-2.0 mol% and the cathodic current density of 25-250 mA cm-2. As a typical example, Fig. 1 shows an XRD pattern of the sample prepared at 100 mA cm-2 for 100 min in the melt after addition of K2TiF60.1 mol% and sponge Ti. Electrodeposition of crystalline Ti metal was confirmed. As shown in the surface SEM image in Fig. 2, the obtained granules have a diameter about 20 μm. No element was detected except for Ti by EDX analysis. In the presentation, the effects of concentration of Ti (IV) ions and current density on the morphology and crystalline orientation will be discussed. Acknowledgement A part of this study was conducted as a collaborative research with Sumitomo Electric Industries, Ltd. R eferences [1] J. O’M. Bockris, G.J. Hills, I.A. Menzies, L. Young, Nature, 178, 654 (1956). [2] D. Inman, S.H. White, J. Appl. Electrochem., 8, 375 (1978). [3] J. De Lepinay, J. Bouteillon, S. Traore, D. Renaud, M.J. Barbier, J. Appl. Electrochem., 17, 294 (1987). [4] D. Wei, M. Okido, T. Oki, J. Appl. Electrochem., 24, 923 (1994). [5] N. Ene, S. Zuca, J. Appl. Electrochem., 25, 671 (1995). [6] A. Robin, R.B. Ribeiro, J. Appl. Electrochem., 30, 239 (2000). [7] J. Song, Q. Wang, X. Zhu, J. Hou, S. Jiao, H. Zhu, Mater. Trans., 55, 1299 (2014). [8] K. Maeda, K. Yasuda, T. Nohira, R. Hagiwara, T. Homma, J. Electrochem. Soc., 162, D444 (2015). Figure 1

The Influence of the Type of Coating on the Cutting Tool Wear During Turning Of 316L Austenitic Stainless Steel

Abstract The paper presents the influence of coatings applied with the use of PVD method on cutting tools on the wear of the tool and compares it with an uncoated P25 cemented carbide plate. During the experiment, two types of TiAlN coatings were used, applied in various proportions, as well as TiN coating. During the tests, the average width of the wear band on the flank face in B VBBzone and the width of KBcrater were monitored. Moreover, the scanning analysis of the tool was conducted in order to determine the intensity of adhesive wear. The lowest values of selected tool wear indicators were found out with the use of TiAlN coating applied in eight layers in the proportions 33/67% -TiN/TiAlN. The scanning analysis proved the highest adhesive wear of the uncoated P25 cemented carbide plate, as well as increased abrasive wear of the flank face and the formation of a crater in comparison with coated plates.

The Ni-Al-Hf Multiphase Diffusion

Abstract The generalized Darken method was applied to simulate the diffusion between γ-Ni| γ’-Ni3Al and γ’-Ni3Al|β-NiAl interfaces. The results of calculations were compared with the experimental concentration’s profiles of nickel, aluminum and hafnium in aluminide and hafnium doped aluminide coatings deposited by the CVD and PVD methods on pure nickel. The method deals with the Wagner’s integral diffusion coefficients and thermodynamic data - activities of components. The experimental results agree with the simulated ones.

Optical Properties of TiO2Nanopowder Doped by Silver (Copper) during Synthesis or PVD Method

Titanium dioxide doped nanopowders were prepared in two ways: (i) by applying a sol–gel method and (ii) by applying the sol–gel synthesis as the first step for pure TiO2 preparation, and next, doped by using magnetron sputtering technique, that is one of a physical vapour deposition method. Silver and copper (Ag, Cu) metals were used as the dopants. Prepared samples were investigated by scanning electron microscope, X-ray diffraction and UV-Vis spectroscopy. The effect of the dopants’ nature and the applied doping method were studied. The results showed that each prepared particles are nanocrystalline materials with particles diameter range from 80 nm to 500 nm (depending on the doping method). From optical experiments, it was possible to observe changes in absorbance spectra, which are probably related to interfacial charge transfer and the localized surface plasmon resonance phenomenon.

The Methods of Surface Preparations of Titanium Alloys Applicable for Friction Pairs in Endoprostheses

The paper presents the results of tribological tests on titanium alloys subjected to modification of surface layer. The tests were conducted with metal biomaterials coated with TiN layer and anodized, applied in knee and hip joint endoprostheses. One of the ways of improving abrasion resistance of metal and polyethylene elements of endoprostheses is TiN coating by means of PVD method. It results in getting the metal of high bio-compatibility and more friction resistant. The research were carried out for various friction pairs applied in total knee and hip joint endoprostheses.