Corrosion resistance of multilayer coatings deposited by PVD techniques onto the brass substrate (original) (raw)
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Corrosion-wear behaviour of PVD Cr/CrN multilayer coatings for gear applications
Tribology International, 2009
At present, one of the most important problems in automobile engines and transmission components is due to tribological processes (friction and wear) that in many cases come accompanied by corrosion processes due to the environmental conditions to which these materials are exposed during their lifetime. Both mechanisms can be minimized by means of the development and the application of adequate coatings that combine low friction with a high corrosion and wear resistance.The new tendencies in industrial PVD coatings to improve their properties are focused in the development of new multilayer and nanostructured coatings. These structures allow in a relatively simple way enhancing their tribological properties and the corrosion resistance that can not be reached by means of the traditional monolayer coatings. The background of this type of coatings consists of the stacking up of several layers with good individual tribological and mechanical properties, but every individual layer has a thickness that can be from hundreds of nanometres down to only 5–10 nm. The properties of these nanostructured coatings depend strongly on the thickness modulation of every individual layer.Concerning PVD coatings, the chrome nitride coatings have demonstrated to possess excellent wear resistance properties. In this work, multilayer Cr/CrN coatings with different individual layer thickness have been deposited on substrates of steel F1272 and silicon. The deposition has been carried out by means of the cathodic arc method alternating an atmosphere of pure Ar with a reactive mixture of N2/Ar. The multilayers obtained have been analyzed by means of Glow Discharge Optical Emission Spectroscopy (GD-OES) and in some cases by means of FE-SEM obtaining bilayer (Cr/CrN) periods of the order of 220 and 45 nm. The coating characterization has been complemented with hardness and composition measurements as well as by the performance of several wear and corrosion-wear tests.
Structure of monolayer coatings deposited by PVD techniques
2006
The aim of the research is the investigation of the structure of coatings deposited by PVD technique (reactive magnetron sputtering method) onto the substrate from the CuZn40Pb2 brass. Design/methodology/approach: Microstructure was characterised using optical metallography, scanning and transmission electron microscopy. Findings: The hard PVD coatings deposited by reactive magnetron sputtering method demonstrate structure composed of fine crystallites. In case of the monolayer coatings the columnar structure occurs. Examinations of the PVD coating textures reveal that in most cases they have the binary textures {111} and {100} or {110} and {311}. Research limitations/implications: In order to evaluate with more detail the possibility of applying these coatings in tools, further investigations should be concentrated on the determination of the mechanical and tribological properties of the coatings. Originality/value: The paper contributes to better understanding and recognition the structure of thin coatings deposited by PVD techniques.
Comparison of the PVD coatings deposited onto hot work tool steel and brass substrates
2007
The aim of the research is the investigation of the structure and mechanical properties of monolayers CrN, TiN and multilayers TiN/TiAlN and Ti/TiAlN coatings deposited by PVD techniques onto the substrate from the X37CrMoV5-1 steel and CuZn40Pb2 brass. Design/methodology/approach: The microhardness tests were made on the dynamic ultra-microhardness tester. Tests of the coatings' adhesion to the substrate material were made using the scratch test. The wear and friction tests were performed on a standard pin-on-disc device. Findings: The monolayer PVD coatings deposited onto hot work steel and brass substrate demonstrate the high hardness, adhesion and wear resistance. The critical load L C2 , which is in the range 32-60 N, depends on the coating and substrate type. The friction coefficient for the investigated coatings is within the range of 0.33-0.75. Practical implications: The investigation results will provide useful information to applying the PVD coating for the improvement of mechanical properties of the hot work tool steels and brass substrates. Originality/value: It should be stressed that the mechanical properties of the PVD coatings obtained in this work are very encouraging and therefore their application for products manufactured at mass scale is possible in all cases where reliable, very hard and abrasion resistant coatings, deposited onto tools steel and brass substrate are needed.
Materials
This work is devoted to the study of the formation of nanostructured multilayer coatings (TiZr/Nb)N on the surface of an AISI 321 steel substrate depending on the deposition parameters of the Arc-PVD method. The results of the X-ray diffraction analysis showed the formation of solid solution (TiNb)N and ZrN in the multilayer coatings with an FCC structure, ε-NbN with a hexagonal structure, as well as with a small volume fraction of the ε-Ti2N and β-Nb2N phase. On the basis of phase composition data, it is possible to assume that an increase in the number of bilayers leads to a decrease in the nitrogen concentration in the bilayers and, consequently, to a decrease in the volume fraction of ε-NbN and β-Nb2N nitrides. In all investigated systems obtained at −100 V and −200 V bias potentials, ε-NbN is the main phase. The study of the element distribution over the thickness of the (TiZr/Nb)N coating confirms the results of the X-ray diffraction analysis. The use of the structure model in...
(Ti,Cr)N and Ti/TiN PVD coatings on 304 stainless steel substrates: wear-corrosion behaviour
Thin Solid Films, 1999
When hard nitrides coatings work in aggressive environments, wear phenomena occur in conjunction with corrosion processes; hence the characterisation of wear and corrosion resistance, considered as two distinct aspects, cannot be regarded as representative of the real degradation process, where the interactions between the two phenomena become extremely important. In this work wear-corrosion tests were performed by means of a laboratory-made apparatus, where the electrochemical characterization can be easily carried out. TiN coatings (with and without the presence of a Ti underlayer) and (Ti,Cr)N coatings were tested under different wear conditions in a sodium chloride solution. The results were compared and the different behaviour was interpreted in terms of film texture and residual stresses due to the PVD process. The (Ti,Cr)N deposits, which have the best intrinsic corrosion resistance, turned out to be the less resistant coatings to the wear-corrosion process, probably because residual stress was much higher than in TiN, making the coating more brittle and poorly adherent to the substrate. The TiN/Ti samples showed the best behaviour under wear-corrosion, which can be explained by a better adhesion of the coating, enhanced by the titanium underlayer. Moreover, the presence of the Ti underlayer proved to be effective in reducing the residual stresses in the TiN layer.
COMPARATIVE STUDY OF PROPERTIES OF Ti BASED COATINGS DEPOSITED BY SELECTED PVD TECHNIQUES
2012
Mechanical and tribological properties of thin TiN, TiAlN and KTRN coatings applied by two PVD techniques were investigated. PVD techniques of ARC and SARC were used for the deposition of thin coatings onto HSS Co5 steel substrates. Conventional types of coatings (TiN and TiAlN monolayers) and an advanced type of coating (Ti and Al based KTRN monolayer deposited using SARC) with smaller microdrops on the surface were analyzed by standard techniques in order to asses the surface status and quality – coating thickness, chemical composition, nano-hardness, Young ́s modulus, and tribological properties at room temperature. Nanohardness values of TiN, TiAlN and KTRN coatings were 31.33GPa, 26.05GPa and 30.42 GPa, respectively. Coefficient of friction (COF) values of TiN, TiAlN and KTRN coatings were 0.86, 0.49 and 0.63, respectively. The roughness Ra of TiN, TiAlN, and KTRN coatings was 0.71μm, 0.33 μm, and 0.66 μm, respectively. High roughness and larger contact surface area of the syst...
Corrosion Performance of Titanium-Based Composite Coatings Deposited by Physical Vapour Deposition
Proceedings of the Estonian Academy of Sciences. Engineering
Titanium-based coatings deposited by physical vapour deposition (PVD) techniques are used routinely to improve the wear and corrosion resistance of a surface. TiN-coated stainless steel shows good corrosion resistance. Further improvement of the corrosion behaviour can be achieved by the deposition of multilayer coatings, including an intermediate layer with isolator properties or another type of conductivity. The investigated single-and multilayer coatings show high values of polarisation resistance. The coatings deposited within the TiN , Ti-Cr-ON and Ti-ON systems onto austenitic stainless steel substrates (AISI 321) significantly decrease the density of the corrosion current and move the corrosion potential of coated specimens to the passivity zone of the substrate. At the same time, there is no significant difference in the corrosion behaviour of singlelayer and multilayer coatings. The factors of structure perfection predominate over those of the electron properties of the coating materials.
Surface and Coatings Technology, 2006
The structure and the corrosion performance of Zn coatings formed by pack cementation and fluidized bed reactor at 250, 350, 380 and 400°C have been studied. From this investigation, it turned out that these coatings are composed of two layers referring to γ-Fe 11 Zn 40 and δ-FeZn 10 phases of the Fe-Zn phase diagram. Furthermore, in the pack coatings, inclusions were detected, which are composed of Fe and Zn at almost equal concentrations. Concerning the corrosion, a mechanism of stress corrosion has been identified. The corrosion performance of the studied coatings is similar to that of the hot-dip galvanized coatings, although the deposition method is different.
Journal of Alloys and Compounds, 2009
The aim of the work is to study the effects of different plating modes on the microstructure and corrosion resistance of Zn–Ni alloy coatings. Zn–Ni alloy coatings were deposited by direct current (DC), pulse current (PC) and pulse reverse current (PRC) methods, respectively. The surface morphology and the grain size were investigated by SEM and XRD. The corrosion resistance of the alloy coatings was evaluated in 3.5% NaCl solution by electrochemical impedance spectroscopy (EIS) technique and polarizing curves method. The results showed that the crystal grains of the alloy coatings prepared by DC, PC and PRC, respectively, became smaller and smaller in order, and the coating surface became compacter and smoother correspondingly. The alloy coatings were composed of a large number of γ-Zn–Ni alloy and a small quantity of η-Zn–Ni. The relative intensities corresponding to crystal face γ (4 1 1, 3 3 0) and η (1 1 2) of alloy coatings deposited by DC, PC and PRC, respectively, were decreased gradually, while the half width of peaks were increased, which illustrated that the crystal grains of the alloy coatings were fine. This was consistent with the surface morphology of the alloy coatings. The results of EIS and polarizing curve tests showed that the corrosion resistance of Zn–Ni alloy coatings deposited by PRC method was the best, and then by PC and DC in sequence. The corrosion resistance of the alloy coatings depended on the alloy structure and composition, the best corrosion resistance of the Zn–Ni alloy coatings deposited by PRC was attributed to its fining of the crystal grains and the dense structure.