Journal articles: 'Intermetallic Coatings'

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Deng, Chun Ming, Min Liu, Chang Guang Deng, Hong Liang Dai, and Ke Song Zhou. "Preparation and Characterizations of NiTi Intermetallic Coatings." Advanced Materials Research 291-294 (July 2011): 80–83. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.80.

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Much attention has been paid to NiTi intermetallic coating for enhancing cavitation erosion resistance property due to its shape memory effect. In this paper two processes were used to deposit NiTi intermetallic coatings. Process 1 was the deposition of NiTi intermetallic coating using warm spray process with NiTi intermetallic powder as feedstock, and solution treatment was subsequently performed. Process 2 was a mixture process of warm spray and laser treatment. Ni-Ti coating was first deposited via warm spray process with Ni-cladding Ti as feedstock, and laser-treatment was performed to realize the alloying of Ni-Ti. The microstructure and phase compositions for NiTi intermetallic coatings were characterized by means of SEM and XRD. The fundamental properties for NiTi intermetallic coatings were also analyzed.

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Chmielewski, Tomasz, Piotr Siwek, Marcin Chmielewski, Anna Piątkowska, Agnieszka Grabias, and Dariusz Golański. "Structure and Selected Properties of Arc Sprayed Coatings Containing In-Situ Fabricated Fe-Al Intermetallic Phases." Metals 8, no. 12 (December 13, 2018): 1059. http://dx.doi.org/10.3390/met8121059.

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The paper presents the results of research on the production by means of arc spraying of composite coatings from the Fe-Al system with participation of in-situ intermetallic phases. The arc spraying process was carried out by simultaneously melting two different electrode wires, aluminum and steel. The aim of the research is to create protective coatings with a composite structure with a significant participation of FexAly as an intermetallic phases reinforcement. The synthesis of intermetallic phases takes place during the (in-situ) spraying process. Currently most coatings involving intermetallic phases are manufactured by different thermal spraying methods using coating materials in the form of prefabricated powders containing intermetallic phases. The obtained results showed the local occurrence of intermetallic phases from the Fe-Al system, and the dominant components of the structure have two phases, aluminum solid solutions in iron and iron in aluminum. The participation of intermetallic phases in the coating is relatively low, but its effect on the properties of the coating material is significant.

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Topic, M., Richard P. Vinci, Zakhelumuzi Khumalo, and C. Mtshali. "Effect of Intermetallics on Pt-Al Surface Coatings Colour." Defect and Diffusion Forum 353 (May 2014): 259–62. http://dx.doi.org/10.4028/www.scientific.net/ddf.353.259.

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We investigated two coatings, Pt:Al and Pt3:Al, deposited onto pure Al substrates. After annealing at 500°C for 2 hours in vacuum, the Pt:Al coating became “matt silver” while the Pt3:Al colour was “old gold”. Although the deposited coatings were relatively smooth, rope-and ridge-like morphologies were observed in the annealed Pt:Al and Pt3:Al coatings, respectively. X-ray diffraction analyses revealed the presence of Al21Pt6and Al2Pt intermetallics in annealed Pt:Al while only the Al2Pt intermetallic phase was observed in the annealed Pt3:Al coatings. RBS spectra showed an increase of coating thickness by four times in the Pt:Al whilst the coating thickness was doubled in the Pt3:Al coatings. The changes to color, surface morphology, and thickness caused by thermal annealing were attributed to the structural characteristics of the most dominant phases.

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Ismailov, M., I. Ablakatov, and I. Alpysbay. "A Study on the Possibilities of Obtaining Intermetallic Coating of Al-Cu and Cu-Zn Systems Deposited on Metal Carrier." Eurasian Chemico-Technological Journal 19, no. 1 (June 19, 2017): 81. http://dx.doi.org/10.18321/ectj506.

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The research aimed at investigating the possibility of obtaining thin intermetallic films, which can be used as thermal control coatings for spacecraft. The coating films build the passive part of the overall thermal control system of a spacecraft, thus they must provide strong adhesion with the carrier material and have high functional characteristics, optical ones in particular. The study concerned issues of synthesis of stable intermetallic phase of Al4Cu9, Al2Cu, Cu5Zn8 on aluminum and copper carriers by magnetron layer-wise sputtering of reagents. They have looked into patterns of emergence of intermetallic coating applying modes of "rapid" and "slow" sputtering of reagents, applying various thicknesses of sputtered layers of reagents, temperature of the carrier, heat treatment of sprayed coatings. Incomplete and complete modes of synthesis of intermetallic coverage have been discovered. Obtained cross-sectional images of coatings, outcomes of microanalyzer scanning of reagent distribution through the thickness of sputtered coatings, microhardness values, optical absorption and emission ratios, unit of electric resistances, adhesion to the carrier. Obtained prototypes of intermetallic thermostatic coatings could be used in "solar reflectors" and "solar absorbers" classes. The results of measurements of optical and strength characteristics revealed that the intermetallic films can be used not only as thermostatic coatings for space technology, but also in general mechanical engineering, due to high-end mechanical properties.

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Ndumia, Joseph Ndiithi, Min Kang, Jinran Lin, Jitao Liu, and Hao Li. "Influence of Heat Treatment on the Microstructure and Wear Properties of Arc-Sprayed FeCrAl/Al Coating." Coatings 12, no. 3 (March 11, 2022): 374. http://dx.doi.org/10.3390/coatings12030374.

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Intermetallic compounds formed during heat treatment of alloy coatings affect the coating structure and properties. In order to determine the phase changes and coating performance, FeCrAl (Fe Bal., Cr 26 wt.%, Al 6 wt.%) and Al (99.9 wt.%) coating was sprayed onto low carbon steel substrates and subsequently heat-treated at different temperatures. The effects of heat treatment on the microstructure, phase composition, tensile bonding strength, microhardness, and wear properties of the coatings were analyzed. The as-sprayed coating had a dense, layered structure with an average porosity of 3.6%. The microhardness of the as-sprayed coating was comprised of hard FeCrAl splats and ductile Al splats with an average microhardness value of 494 HV0.1. The coating at 300 °C had the highest tensile strength of 37.5 MPa. At 500 °C, FeAl intermetallic compounds formed at the phase boundaries due to the diffusion of elements. The coating microhardness and wear resistance were affected by the uniform coating structure and the precipitation of FeAl intermetallic compounds. Compared with the annealed coatings, the as-sprayed coating had the lowest wear rate.

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Chen, Xiao, Chengdi Li, Xiaobo Bai, Hao Liu, Shunjian Xu, and Yao Hu. "Microstructure, Microhardness, Fracture Toughness, and Abrasive Wear of In-Situ Synthesized TiC/Ti-Al Composite Coatings by Cold Spraying Combined with Heat Treatment." Coatings 11, no. 9 (August 27, 2021): 1034. http://dx.doi.org/10.3390/coatings11091034.

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TiAl intermetallic compounds, as a new kind of high-performance light-weight structural material, are widely applied in many fields. Titanium carbide (TiC) as the reinforcing phase could improve the mechanical properties, wear resistance, and heat-resistance stability of TiAl intermetallic compounds. Ti(Al, C) mixture powders were deposited by cold spraying at gas temperature of 250 °C, 450 °C, and 550 °C. Then, Ti(Al, C) coatings were annealed at temperatures of 650 °C for different times and following holding at 1100 °C for 3 h. The microstructure, microhardness, fracture toughness, and abrasive wear of Ti-Al composite coatings were investigated. The research results were that the particle size of mixture powders decreased as the ball milling time prolonging. Ti(Al) solid solution appeared in the mixture powders as the milling time increased to 30 h. The average porosity of the coating sprayed at 550 °C was the lowest (0.85%). The as-sprayed coatings exhibited the same phase compositions with the mixture powders. The coating sprayed at gas temperature of 550 °C has the highest microhardness and the lowest weight loss. Ti-Al intermetallic was in-situ synthesized after annealing at 650 °C. The average porosity of the annealed coating (sprayed at 450 °C) was the lowest. The content of Ti-Al intermetallic compounds of the annealed coating sprayed at 450 °C is the highest. The X-ray diffraction (XRD) analysis results are consistent with the EDS analysis of the annealed coatings after annealing at 650 °C. Ti-Al intermetallic compounds were almost completely formed in the three kinds of the coatings after annealing at 650 °C for 20 h and following holding at 1100 °C for 3 h. TiAl and TiAl3 intermetallic phases were in-situ synthesized in the coatings based on the energy dispersive spectroscopy (EDS) and XRD analysis. TiC was also in situ synthesized in the coatings as the annealing temperature increased to 1100 °C. The annealed coating (sprayed at 450 °C) has the highest microhardness, fracture toughness, and wear resistance properties after annealing at 1100 °C for 3 h.

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Khimukhin, S. N., and Kseniia P. Eremina. "Microstructure Peculiarities of Intermetallic and Composite Coatings." Solid State Phenomena 316 (April 2021): 783–88. http://dx.doi.org/10.4028/www.scientific.net/ssp.316.783.

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Coatings were obtained by the method of electrospark deposition (ESD), using Ni-Al intermetallic alloys, steel having been used as cathodes. The structure of samples preliminarily, coated with nickel aluminides of various phase compositions (NiAl, Ni3Al), was investigated. In addition to the indicated anode materials, a complex alloyed metal matrix alloy obtained by the method of self-propagating high-temperature synthesis, was used. It was established that the coating microstructure consisted of columnar crystallites, vertically oriented to the cathode surface. X-ray microanalysis of the transverse sections showed a change in the composition of crystallites along their height. It was found that the content of the cathode components decreased from the surface of the sample to the upper part of its coating, however, the content of the anode components increased. The revealed regularities indicate the fact that the coating structure obtained at ESD, was formed through the stage of liquid-phase mixing, which explained high coating adheasion. The mechanisms of structure formation of both single-layer and two-layer coatings proved to be identical.

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Dyl, Tomasz Cyryl, Robert Starosta, and Robert Skoblik. "Effect of the Unit Pressure on the Selection Parameters of Intermetallic Coatings NiAl and Ni₃Al after Plastic Working." Solid State Phenomena 165 (June 2010): 19–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.165.19.

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Modern materials on intermetallic matrix are in the scope of research of many scientific – research centers in Poland [1]. Intermetallic systematic alloys containing aluminium have high resistance to oxidation, abrasive corrosion and fatigue as well as heat resistance. That is why they are applied in the production of machine parts used in hard service conditions (internal combustion turbine blades, exhaust valves, turbo-blower rotors) [2]. Intermetallic coatings can be obtained by means of plasma spraying. Thermal spraying technology is widely used due to the possibility of increasing the service properties in surface layers (strength property, tribological, anti-corrosive and decorative property) as well as coating application on machine parts elements, on tools for plastic working (forging moulds busters, piston rods, gear wheels teeth, crank journals, valve seats, and combustion engine cylinders) [3, 4]. NiAl and Ni3Al coatings are characterized by high fatigue resistance, heat resistance and considerable corrosion resistance [5]. Coatings obtained by thermal spraying have high surface roughness. Thus, subsequent plastic treatment is advisable for plasma-sprayed intermetallic coatings. Therefore it is vital to define to what extent the change of unit pressure will influence reduction of surface roughness of intermetallic coatings. For this purpose experimental upsetting research was carried out on C45 steel samples having NiAl and Ni3Al coatings for the following unit pressures p = 500 MPa, p = 800 MPa, p = 1100 MPa.

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Wang, Hong Tao, Guan Jun Yang, Chang Jiu Li, and Cheng Xing Li. "Effect of Annealing Treatment on the Structure and Microhardness of Cold-Sprayed Nanostructured FeAl/WC Composite Coating." Key Engineering Materials 373-374 (March 2008): 73–76. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.73.

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Nanostructured FeAl/WC intermetallic composite coatings were prepared by cold spaying of the ball-milled powders. The effect of annealing on the coating structure and microhardness was examined. It was found that the nanocrystalline structure of the milled feedstock was retained in the cold sprayed coatings. The FeAl intermetallic phases were formed from the milled Fe(Al) solid solution during the post-spraying annealing at 550oC. The microhardness of the as-sprayed coating was about 680HV0.1 and it decreased a little with increasing the annealing time at 550oC.

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Li, Sheng Shou, Tian Quan Liang, Xian Fang Yang, and Cui Hua Zhao. "Microstructures and Wear Resistance of Iron-Based Protective Coatings by Supersonic Arc Spraying." Applied Mechanics and Materials 670-671 (October 2014): 554–59. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.554.

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The characteristics in microstructure, surface morphology, chemical composition, hardness and wear resistance of the three protective iron-based compound coatings prepared by Supersonic Arc Spraying (HVAS), were investigated by X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy disperse spectroscopy (EDS) and Rockwell apparatus in this paper. It is indicated that the three coatings are typical layer and compact structures. The coatings are composed of Fe (s.s) phase and various kinds of ferric oxides, chrome carbides and/or intermetallic phase distributing along the interface of lamellar layers. More Cr and Ti, Al elements in the cored wires can degrease the diameter and alternate the morphologies of the holes in the coating, resulting from the formation of oxides, carbides and intermetallic phase during depositing the coating. The results indicate the SXTiAlC coating shows the most excellent wear performance among the three coatings. The wear behavior and mechanism are discussed.

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'Ecuyer, J. D. L., M. Gagné, C. C. Cheng, and G. L. 'Espérance. "EM of hot-dip zinc-iron (galvannealed) coatings." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 1036–37. http://dx.doi.org/10.1017/s0424820100178318.

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Galvannealed coatings have superior weldability and paintability characteristics than conventional zinc coatings. As a result, the market for galvannealed steel sheets is steadily increasing especially in the automotive industry. The formation of the brittle intermetallic Zn-Fe phases, Γ, Γ1, δ, and Z also affects the for- mability properties of the coated steel product. In order to minimize powdering and flaking, the microstructure of the coating must be closely controlled.The characterization of the galvannealed coating microstructure is essential but has proven to be quite difficult. The individual phases cannot be resolved using optical microscopy. X-ray diffraction appears promising, however some of the intermetallic phases are too thin to produce a detectable signal. Electrochemical stripping has been used, but phase identification is ambiguous. Direct observation of the phases using electron microscopy appears to be the best method for characterizing these coatings.

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Lovshenko, F. G., and A. S. Fedosenko. "Plasma coatings made of mechanically synthesized composite powders based on the «iron-aluminum» system." Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), no. 3 (October 20, 2020): 84–92. http://dx.doi.org/10.21122/1683-6065-2020-3-84-92.

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The regularities of the formation of plasma coatings obtained from powders based on the Fe-Al system synthesized by the reaction mechanical alloying method are established. The influence of the processing modes of the compositions in the mechanoreactor on the properties of coatings is revealed. An effective method for controlling the porosity of coatings from developed powders based on a change in the power consumed by the installation is proposed.Plasma coatings have a nonequilibrium phase composition, which, in contrast to the equilibrium one, contains a wide range of metal oxides of the base and alloying elements formed during the spraying. The coating retains submicra – microcrystalline type of structure of powders with a highly developed grain and subgrain boundary. The basis of the coating is intermetallic FeAl. The role of hardening phases is played by ultrafine compounds of intermetallics and oxides.Powder annealing has a significant effect on the structure and properties of coatings and, first of all, on layers from compositions with complex alloying with oxides. Heat treatment increases the density and hardness of coatings and reduces porosity. The study of coating samples after high temperature indicates high heat resistance and the preservation of the microcrystalline type of structure of their bases.

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Yao, Tianyu, Kui Wang, Haiyan Yang, Haiyan Jiang, Jie Wei, Weiping Wu, Hezhou Liu, Qudong Wang, and Wenjiang Ding. "Heat Treatment-Induced Microstructure and Property Evolution of Mg/Al Intermetallic Compound Coatings Prepared by Al Electrodeposition on Mg Alloy from Molten Salt Electrolytes." Materials 14, no. 6 (March 14, 2021): 1407. http://dx.doi.org/10.3390/ma14061407.

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A method of forming an Mg/Al intermetallic compound coating enriched with Mg17Al12 and Mg2Al3 was developed by heat treatment of electrodeposition Al coatings on Mg alloy at 350 °C. The composition of the Mg/Al intermetallic compounds could be tuned by changing the thickness of the Zn immersion layer. The morphology and composition of the Mg/Al intermetallic compound coatings were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron backscattered diffraction (EBSD). Nanomechanical properties were investigated via nano-hardness (nHV) and the elastic modulus (EIT), and the corrosion behavior was studied through hydrogen evolution and potentiodynamic (PD) polarization. The compact and uniform Al coating was electrodeposited on the Zn-immersed AZ91D substrate. After heat treatment, Mg2Al3 and Mg17Al12 phases formed, and as the thickness of the Zn layer increased from 0.2 to 1.8 μm, the ratio of Mg2Al3 and Mg17Al12 varied from 1:1 to 4:1. The nano-hardness increased to 2.4 ± 0.5 GPa and further improved to 3.5 ± 0.1 GPa. The Mg/Al intermetallic compound coating exhibited excellent corrosion resistance and had a prominent effect on the protection of the Mg alloy matrix. The control over the ratio of intermetallic compounds by varying the thickness of the Zn immersion layer can be an effective approach to achieve the optimal comprehensive performance. As the Zn immersion time was 4 min, the obtained intermetallic compounds had relatively excellent comprehensive properties.

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Rodina, A. A., K. E. Dobychina, and O. S. Bondareva. "Changing the structure and properties of hot-dip zinc coatings using diffusion annealing." Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta, no. 4 (2020): 25–33. http://dx.doi.org/10.18323/2073-5073-2020-4-25-33.

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Zinc coatings are widely used to protect steel goods from corrosion. The physics of methods of zinc applying to steel determines the coating morphology. Hot-dip zinc and thermodiffusion coatings are produced on steel by a diffusion mechanism and contain intermetallic phases according to the Fe-Zn diagram; however, they have different phase morphology, corrosion resistance, and consequently, different operating corrosive media. Thermodiffusion coatings have the highest corrosion resistance. However, their applying technique imposes a restraint on the dimensions of goods due to the small size of a chamber, and it requires much more time (several hours) compared to hot-dip zinc coatings applying for several minutes. In this respect, the authors suggest using the diffusion annealing of hot-dip galvanized goods to produce the entire intermetallic structure of the coating. The goal of the paper was to study the influence of the diffusion annealing modes on the microstructure and properties of hot-dip zinc coatings. The study showed the changes in the microstructure and elemental composition of the zinc coating phases as the result of soaking at the temperatures of 500 and 600 °С for 5 and 10 minutes. The authors researched the influence of annealing modes on the porosity of a coating and its microhardness. The coatings were quickly tested for corrosion resistance in the initial state and after thermal treatment. As a result of diffusion annealing, zinc coating becomes completely intermetallic, more homogeneous; its chemical composition becomes uniform. The study identified that to obtain the balance of physical-mechanical and technological properties, it is recommended to use the diffusion annealing mode with a temperature of 500 °С and soaking in a furnace for 5 minutes.

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Ivanaysky, Victor V., N. T. Krivochurov, and V. F. Aulov. "Improving the Characteristics of Wear-Resistant Coatings Obtained by HDTV-Boration, their Modification by Intermetallic Compounds of Fe-Al and Ni-Al Systems." Materials Science Forum 992 (May 2020): 640–46. http://dx.doi.org/10.4028/www.scientific.net/msf.992.640.

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Innovative technology of HDTV-borating, that is distinguished by high hardness, strength, wear resistance and corrosion resistance occupies a special place among the hardening processes for steels and construction materials. During the new technology process HDTV-boration of structural steel 65Mn (65Г in Russian) under a mix layer of charge mixture based on fused borate fluxing agent P-0.66, boron carbide and intermetallic compounds FexAly, NixAly. Using the methods of X-ray phase analysis, spectrography and metallography, the composition and structure of coatings were determined, the microhardness distribution over the coating thickness was studied. In the coatings, new phases of intermetallic compounds, the double superhard boride Fe2AlB2, were found; in the coatings, the base iron boride is FeB, what leads to an increase in their hardness and wear resistance. Modification of boride coatings formed by intermetallic compounds with melting temperatures close to the process temperature of HFC surfacing leads to a decrease in the cracks number and the appearance of new consumer qualities of the material.

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Liu, Zhikai, Weiqi Lian, Cansen Liu, and Xiaohua Jie. "Fabrication of In Situ rGO Reinforced Ni–Al Intermetallic Composite Coatings by Low Pressure Cold Spraying with Desired High Temperature Wear Characteristics." Materials 16, no. 9 (May 5, 2023): 3537. http://dx.doi.org/10.3390/ma16093537.

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In this study, the surface of aluminum powder was uniformly coated with in situ reduced graphene oxide (r-GO) sheets (Al/r-GO). The Ni powder, Al2O3 powder, and Al/r-GO powders were mixed uniformly in a mass ratio of 20:6:4. In situ rGO-reinforced Ni–Al intermetallic composite coatings were successfully prepared using low-pressure cold spraying and subsequent heat treatment. The microstructure and phase of the composite coatings were characterized using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The high-temperature wear test was conducted at 200 °C, 400 °C, and 600 °C to understand the mechanism. The results indicate that the in situ rGO-reinforced Ni–Al intermetallic composite coatings exhibit a 33.3% lower friction coefficient and 26% lower wear rate in comparison to pure Ni–Al intermetallic coatings, which could be attributed to the generation of an easy-shearing transferred film between the coating and grinding ball.

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Alba-Galvín, Juan, Leandro González-Rovira, Manuel Bethencourt, Francisco Botana, and José Sánchez-Amaya. "Influence of Aerospace Standard Surface Pretreatment on the Intermetallic Phases and CeCC of 2024-T3 Al-Cu Alloy." Metals 9, no. 3 (March 12, 2019): 320. http://dx.doi.org/10.3390/met9030320.

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A standard three-step surface pretreatment employed in the aerospace sector for Al alloys have been investigated prior to the generation of cerium conversion coatings (CeCC) on aluminium-copper alloy 2024. Two pretreatments were analysed, one without final acid etching (Pretreatment 1) and another with this step (Pretreatment 2). Both pretreatments affect the alloy intermetallic phases, playing a key role in the development of the CeCC, and also in the susceptibility to localised corrosion in NaCl medium. Scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX) revealed that after Pretreatment 2, Al(Cu,Mg) phases were partially or totally removed through dealloying with their subsequent copper enrichment. Conversely, none of these intermetallic phases were affected when the final acid step was not employed (Pretreatment 1). Meanwhile, Al-Cu-Fe-Mn-(Si) phases, the other major Al–Cu alloys intermetallics, suffers minor changes through the whole pretreatments chain. The protective efficiency of CeCC was evaluated using electrochemical techniques based on linear polarisation (LP) and electrochemical impedance spectroscopy (EIS). Samples with CeCC deposited after the Pretreatment 1 gave higher polarisation resistance and impedance module than CeCC deposited after Pretreatment 2. SEM-EDX and X-ray photoelectron spectroscopy analysis (XPS) indicate that the main factors explaining the corrosion resistance of the coatings is the existence of Al(Cu,Mg) intermetallics in the surface of the alloy, which promote the deposition of a cerium-based coating rich in Ce4+ compounds. These Al(Cu,Mg) intermetallics were kept in the 2024 alloy when acid etching was not employed (Pretreatment 1).

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Sainis, Salil, and Caterina Zanella. "A Study of the Localized Ceria Coating Deposition on Fe-Rich Intermetallics in an AlSiFe Cast Alloy." Materials 14, no. 11 (June 3, 2021): 3058. http://dx.doi.org/10.3390/ma14113058.

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Corrosion inhibiting conversion coating formation is triggered by the activity of micro-galvanic couples in the microstructure and subsequent local increase in pH at cathodic sites, which in the case of aluminium alloys are usually intermetallics. Ceria coatings are formed spontaneously upon immersion of aluminium alloys in a cerium conversion coating solution, the high pH gradient in the vicinity of intermetallics drives the local precipitation of ceria conversion compounds. Cu-rich intermetallics demonstrate a highly cathodic nature and have shown the local precipitation reaction to occur readily. Fe-rich intermetallics are, however, weaker cathodes and have shown varied extents of localized deposits and are in focus in the current work. Model cast Al-7wt.%Si alloys have been designed with 1 wt.% Fe, solidified at different cooling rates to achieve two different microstructures, with big and small intermetallics, respectively. Upon subjecting the two microstructures to the same conversion coating treatment (immersion in a 0.1 M CeCl3 solution) for a short period of 2 h, preferential heavy deposition on the boundaries of the big intermetallics and light deposition on the small intermetallics was observed. Based on these observations, a mechanism of localized coating initiation at these Fe-rich intermetallic particles (IM) is proposed.

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Zhu, Sheng, Guo Feng Han, Xiao Ming Wang, Yu Xiang Liu, and Chao Ji Zhou. "Tribological Properties of TiAl Coating on Aluminum Alloy Surface by Supersonic Particles Deposition." Applied Mechanics and Materials 633-634 (September 2014): 870–73. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.870.

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In this study, Gamma TiAl intermetallic alloy protective coating was deposited on the surface of 5803 aluminum alloy by supersonic particles deposition. Researchers observed the surface morphology of the coating by SEM, and researched tribological properties of the substrate material and the coating by CETR friction and wear tester and Talysurf 5P-120 surface morphology tester. The results show that,the bonding mechanism of the Gamma TiAl intermetallic alloy coating and substrate is mechanical interlocking and metallurgical bonding. The abrasion mechanism of Gamma TiAl intermetallic alloy coating is abrasive Wear. The friction coefficients of the coating are all lower than 5083 alumium alloy. The friction volume of coatings reduced 36.7% than 5083 aluminum alloy with the friction loads 50N. TiAl coating has great function to anti-attrition and wearability.

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Chen, Xiao, Chengdi Li, Shunjian Xu, Yao Hu, Gangchang Ji, and Hongtao Wang. "Microstructure and Microhardness of Ni/Al-TiB2 Composite Coatings Prepared by Cold Spraying Combined with Postannealing Treatment." Coatings 9, no. 9 (September 4, 2019): 565. http://dx.doi.org/10.3390/coatings9090565.

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Ni/Al-TiB2 composite powders were deposited on the surface of 316L stainless-steel substrates by cold spraying at gas temperatures of 250 and 450 °C, respectively. Then, the as-sprayed coatings were annealed at 650 °C for 10, 20, and 30 h. The experimental results showed that the average porosity of as-sprayed coating dropped from about 0.68% to 0.054% as the cold spraying gas temperature increased. The contents of Ni, Al, and TiB2 in the as-sprayed coatings were different from that of the Ni/Al-TiB2 composite powders. The main phase compositions of the as-sprayed Ni/Al-TiB2 coatings were the same as those of composite powder, consisting only of pure Ni, Al, and TiB2 phases. TiB2 as a reinforced particle in the as-sprayed coating could obviously increase the microhardness of the coatings. NiAl3 and Ni2Al3 intermetallic compounds were synthesized in situ in all of the annealed coatings, and the average contents of NiAl3 and Ni2Al3 intermetallic compounds increased as the cold spraying gas temperature increased. The distribution of TiB2 particle was changed as the annealing times increased, which changed from more comparative uniform distribution to accumulation. The average porosity of the annealed coatings increased as the annealing time increased. The microhardness of Ni/Al-TiB2 coatings annealed at 650 °C for 10 h was increased remarkably due to the reinforcement role of TiB2 particles and NiAl3 and Ni2Al3 intermetallic compounds.

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Sun, Chufeng, Yanbin Wang, Qiong Su, Zhiguang Guo, and Lei Shi. "The Tribological Property and Microstructure of Ni-Ti Coating Prepared by Electrodeposition and Heat Treatment." Advances in Materials Science and Engineering 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/8750657.

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Ni-Ti coatings were fabricated by the electrodeposition in a Ni plating bath containing Ti power and heat treatment in nitrogen atmosphere. The surface morphology and microstructure of the Ni-Ti coating before and after heat treatment were analyzed by means of scanning electron microscopy and X-ray diffraction. The friction and wear behaviors of two different coatings were evaluated on a ball-on-disk UMT-2MT test rig. It was found that the phase structure of Ni-Ti coating heated in nitrogen was much different from that of the as-deposited Ni-Ti coating. Namely, the new intermetallic compounds, including Ni3Ti, NiTi, and NiTi2, and TiN were detected in the coating after heat treatment by the XRD analysis and contributed to greatly increasing the hardness and tribological property of the Ni-Ti coating, owing to the strengthening effect of the hard intermetallic compounds and TiN phase. At the same time, a small amount of intermetallic compounds and TiN was transferred from the composite coating to the rubbing surface of the counterpart steel ball during the sliding, which also contributed to decreasing the friction coefficient and increasing the wear resistance.

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Doronin, O. N., D. S. Gorlov, E. N. Azarovsky, and A. S. Kochetkov. "STUDY OF THE STRUCTURE AND PROPERTIES OF A HEAT-RESISTANT COATING AT HIGH-TEMPERATURE DEFORMATION OF SAMPLES FROM TITANIUM INTERMETALLIC ALLOY." Aviation Materials and Technologies, no. 1 (2021): 61–70. http://dx.doi.org/10.18577/2713-0193-2021-0-1-61-70.

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In order to set up research works and determine the requirements for the promising options of protective coatings he paper studies an experimental version of a complex multilayer heat-resistant ion-plasma coating at high-temperature deformation of samples from an intermetallic titanium alloy. The article shows that at high values of residual deformation (up to 11%) of a base made of an intermetallic titanium alloy the multilayer coating is capable of providing sufficiently high level of protective properties.

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Chmielewski, Tomasz, Marcin Chmielewski, Anna Piątkowska, Agnieszka Grabias, Beata Skowrońska, and Piotr Siwek. "Phase Structure Evolution of the Fe-Al Arc-Sprayed Coating Stimulated by Annealing." Materials 14, no. 12 (June 10, 2021): 3210. http://dx.doi.org/10.3390/ma14123210.

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The article presents the results of research on the structural evolution of the composite Fe-Al-based coating deposited by arc spray with initial low participation of in situ intermetallic phases. The arc spraying process was carried out by simultaneously melting two different electrode wires, aluminum and low alloy steel (98.6 wt.% of Fe). The aim of the research was to reach protective coatings with a composite structure consisting of a significant participation of FexAly as intermetallic phases reinforcement. Initially, synthesis of intermetallic phases took place in situ during the spraying process. In the next step, participation of FexAly fraction was increased through the annealing process, with three temperature values, 700 °C, 800 °C, and 900 °C. Phase structure evolution of the Fe-Al arc-sprayed coating, stimulated by annealing, has been described by means of SEM images taken with a QBSD backscattered electron detector and by XRD and conversion electron Mössbauer spectroscopy (CEMS) investigations. Microhardness distribution of the investigated annealed coatings has been presented.

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KRÁL, JOZEF, MILAN FERDINANDY, DANIEL KOTTFER, ILDIKÓ MAŇKOVÁ, and LADISLAV CENIGA. "TRIBOLOGICAL AND REFRACTORY PROPERTIES OF TiAl3 INTERMETALLIC ALLOY." Surface Review and Letters 16, no. 04 (August 2009): 623–29. http://dx.doi.org/10.1142/s0218625x09013074.

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Substrates of Ti -based coatings were investigated regarding wear resistance and refractoriness. Substrates with and without the TiAl 3 coating formed by the ion plating method with evaporation of Al are considered. Additionally, the paper briefly presents principles of kinetics of the formation of the TiAl 3 coating.

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DING, YUWEN, XIAOCHUN CHEN, YA LIU, and XUPING SU. "EFFECT OF DIFFUSION PROCESS ON COATING IN HOT-DIPPED ALUMINIZED STEEL." Surface Review and Letters 26, no. 10 (November 14, 2019): 1950070. http://dx.doi.org/10.1142/s0218625x19500707.

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Aluminized steels possess excellent corrosion resistance due to the formation of Al-Fe solution phases and intermetallic compounds in coatings. Ni was added to baths to further improve the corrosion resistance of the coatings at high temperature. Here, the role of Ni in the formation of coatings and the effect of diffusion process on the developing of coatings were investigated. 45 steels were immersed in Al-Ni baths (Al-1mass% Ni, Al-3mass% Ni, and Al-5mass% Ni) and diffusion-treated at 1023 and 1123[Formula: see text]K for 20, 40 and 100[Formula: see text]min, respectively. The coatings of samples were analyzed via scanning electron microscopy (SEM) along with energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) was further used to confirm the types of phases that formed during diffusion treatment. The formations of intermetallic coating layers were also analyzed via the diffusion path. More continuous Al3Ni layer and compact coating were obtained with diffusion treatment at 1023[Formula: see text]K for 40[Formula: see text]min.

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Kovtunov, A. I., A. M. Ostryanko, О. V. Shashkin, and Т. V. Semistenova. "Investigation of diffusion annealing processes of steels with multi-layer Ni–Al coating." Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Universitiesʹ Proceedings. Powder Metallurgy аnd Functional Coatings), no. 2 (June 19, 2019): 68–74. http://dx.doi.org/10.17073/1997-308x-2019-2-68-74.

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Ni–Al intermetallics have high heat resistance and therefore they are used as coatings for steel parts running under high temperature conditions. A method for liquid-phase aluminizing of preliminary nickel-plated steel samples followed by diffusion annealing was offered to form such coatings. Liquid-phase aluminizing can form the second aluminum layer on the nickel-plated steel and diffusion annealing provides formation of a coating based on Ni–Al intermetallics. Diffusion annealing (t = 650÷850 °C, τ = 1, 2 and 5 hours) was done at samples coated with aluminum at 750 °С. It was found that the technology offered ensures forming surface intermetallic layers with a thickness depending on the temperature and time of annealing. Annealing at 650÷800 °С during 1÷5 hours provides forming mainly up to 50–140 μm thick Ni2Al3 layer, while NiAl and Ni3Al layers featuring the highest heat resistance are formed at 850 °С during 5 hours. The heat resistance of these coatings showed that due to refractory NiAl layer formation on the surface, the sample resists to failure at a testing temperature of 750 °С during 300 hours.

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Jia, Qianqian, Deyuan Li, Sheng Guan, Zhuang Zhang, Nannan Zhang, and Wenzhen Zhao. "Oxidation Resistance and Modification Reaction Mechanism of Al Coating Sprayed on Pure Ti Substrate." Advances in Materials Science and Engineering 2018 (October 15, 2018): 1–9. http://dx.doi.org/10.1155/2018/1403521.

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An Al coating was deposited on the surface of pure Ti substrate by arc spray technology. In order to enable the modification reaction between the Al coating and Ti substrate, the specimen was heated to a temperature above the melting point of Al. Oxidation testing of the uncoated Ti and coated specimen was conducted at 1073 K under an air atmosphere. The microstructure, chemical composition, and phase determination of the coatings and interfaces, before and after modification treatment, were done using SEM, EDS, and XRD methods. The relationships between the modification results and time and temperature were discussed. The results showed that, after heating at 973 K for 5 hours, there was still sufficient Al on the surface of the specimen. Only intermetallic TiAl3 was formed in the diffusion region. After heating at 1073 K for 5 hours, all the Al elements diffused into the Ti substrate. Intermetallics TiAl2 and Ti3Al were also formed in the diffusion front of Al, in addition to TiAl3. After heating at 1173 K for 5 hours, a new intermetallic TiAl phase was formed at the interface of TiAl2 and Ti3Al. As the modification reaction time was prolonged at 1173 K, the formation of intermetallics TiAl2, TiAl, and Ti3Al were all increased. Among them, the formation amount of TiAl2 > Ti3Al > TiAl. The specimen after modification treatment had better high temperature oxidation resistance than the pure Ti substrate without coating.

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Kania, Henryk, Anżelina Marek, Michał Zoran, Marcin Spławski, Przemysław Kupczyk, Mateusz Wiewióra, and Aleksandra Kupczyk. "Microstructure and Corrosion Behavior of ZnAl12Mg3Si0.3 Double-Batch Hot-Dip Coatings." Materials 16, no. 6 (March 8, 2023): 2162. http://dx.doi.org/10.3390/ma16062162.

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This article presents the microstructure (SEM) and corrosion behavior of ZnAl12Mg3Si0.3 (ZAMS) coatings obtained by the double hot-dip method on Sebisty steel with increased strength. On the basis of chemical composition studies in micro-areas (EDS) and phase composition studies (XRD), structural components of the coating and corrosion products formed on the coating surface after exposure to the neutral salt spray (NSS) test (EN ISO 9227) were identified. The presence of the Fe(Al,Si,Zn)3 intermetallic phase was found in the Fe-Al intermetallic layer, while in the outer layer, dendrites rich in Al and Zn were identified. In these dendrites, the eutectics of Zn/MgZn2 and precipitates of the MgZn2 phase and Si were located. The NSS test showed better corrosion resistance of ZAMS coatings compared to conventional zinc hot-dip coatings. The increase in corrosion resistance is due to the formation of favorable corrosion products: simonkolleite—Zn5(OH)8Cl2·H2O and hydrozincite—Zn5(OH)6(CO3)2, and the presence of the MgZn2 phase in the coating, which is more anodic than other structural components.

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Góral, M., P. C. Monteiro, P. Sosnowy, M. Woźniak, T. Kubaszek, and B. Kościelniak. "The formation of Si-aluminide coating formed by plasma spraying and subsequent diffusion annealing on Ti-Al-7Nb intermetallic alloy." Archives of Materials Science and Engineering 117, no. 2 (October 1, 2022): 49–56. http://dx.doi.org/10.5604/01.3001.0016.1775.

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In the article, the kinetic growth phenomena of aluminide coating formed by plasma spraying pure Al-Si powder and subsequent diffusion annealing on TiAl intermetallic alloy in inert atmosphere were investigated. The Al-Si powder was thermal sprayed (APS) on TiAl7Nb intermetallic alloy and annealed in Ar atmosphere during 5, 15, 30, 60, 240 and 480 min. The kinetic growth of the coating was observed using the scanning electron microscopy method (SEM), and chemical composition was analysed using the EDS method. The Kirkendall Effects pores formation, as well as titanium silicides on the grain boundary of TiAl3, was found. The oxidation resistance of the developed coating might be analysed in further work. The developed coating might be used for the production of protective aluminide coatings on TiAl intermetallic alloys. The description of aluminide coating formation in a new technological process.

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García, Felipe, Armando Salinas-Rodríguez, and Enrique Nava-Vázquez. "The Role of Ti Inoculation of Al-Zn-Si Coating Alloys on the Formation of Intermetallic Compounds by Interaction with Solid Steel." Materials Science Forum 560 (November 2007): 97–102. http://dx.doi.org/10.4028/www.scientific.net/msf.560.97.

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The reaction between solid steel and liquid Al-Zn-Si alloy leads to the formation of a solid intermetallic interfacial layer. In the case of industrial Al-43.5Zn-1.5Si coated steel strips, the thickness of the intermetallic layer is on average 1.35 μm and the kinetics of the reaction is controlled by the effect of Si on Al and Fe diffusivities through the solid intermetallic layer. In this paper it is shown that the thickness of the intermetallic interfacial layer decreases as the Si content in the liquid alloy increases. EDXS microanalysis at the interface of industrial coated steel strips shows that the interfacial intermetallic compounds are chemically similar to those formed in the bulk of Al-43.5Zn-1.5Si liquid baths in continuous coating lines. Differential acid dissolution of the coatings reveals that the intermetallic layer is not planar at the interface with the coating overlay and is formed by grains of different size and chemical composition. Addition of minute quantities of Ti to the Al-Zn-Si liquid alloy causes changes in the morphology of the intermetallic layer and an overall refining of the microstructure.

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31

Sweet, J. D., and D. J. Casadonte. "Sonochemical Formation of Intermetallic Coatings." Chemistry of Materials 6, no. 11 (November 1994): 2113–17. http://dx.doi.org/10.1021/cm00047a035.

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Vojtěch, Dalibor, Tomáš Kubatík, Markéta Pavlíčková, and Jaroslav Maixner. "Intermetallic protective coatings on titanium." Intermetallics 14, no. 10-11 (October 2006): 1181–86. http://dx.doi.org/10.1016/j.intermet.2005.11.035.

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33

Sienkiewicz, Judyta, Seiji Kuroda, Hideyuki Murakami, Hiroshi Araki, Maciej Giżyński, and Krzysztof J. Kurzydłowski. "Fabrication and Oxidation Resistance of TiAl Matrix Coatings Reinforced with Silicide Precipitates Produced by Heat Treatment of Warm Sprayed Coatings." Journal of Thermal Spray Technology 27, no. 7 (September 5, 2018): 1165–76. http://dx.doi.org/10.1007/s11666-018-0751-x.

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Abstract Ti-Al-based intermetallics are promising candidates as coating materials for thermal protection systems in aerospace vehicles; they can operate just below the temperatures where ceramics are commonly used, and their main advantage is the fact that they are lighter than most other alloys, such as MCrAlY. Therefore, Ti-Al-Si alloy coatings with five compositions were manufactured by spraying pure Ti and Al-12 wt.% Si powders using warm spray process. Two-stage hot pressing at 600 and 1000 °C was applied to the deposits in order to obtain titanium aluminide intermetallic phases. The microstructure, chemical composition, and phase composition of the as-deposited and hot-pressed coatings were investigated using SEM, EDS, and XRD. Applying of hot pressing enabled the formation of dense coatings with porosity around 0.5% and hard Ti5(Si,Al)3 silicide precipitates. It was found that the Ti5(Si,Al)3 silicides existed in two types of morphologies, i.e., as large particles connected together and as small isolated particles dispersed in the matrix. Furthermore, the produced coatings exhibited good isothermal and cyclic oxidation resistance at a temperature of 750 °C for 100 h.

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Jin, Kwang-Hyeok, and Min-Suk Oh. "Effects of the Mg Content on Microstructural and Corrosion Characteristics of Hot-Dip Al–Si–Mg Alloy-Coated Steel Sheets." Materials 16, no. 17 (August 25, 2023): 5827. http://dx.doi.org/10.3390/ma16175827.

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Hot-dip Al–Si alloy coatings with excellent resistance to corrosion and high-temperature oxidation have emerged as promising lightweight substitutes for conventional corrosion-resistant coatings. The introduction of Mg can be an effective strategy for enhancing the sacrificial protection capability of Al–Si coatings. In this study, the effects of Mg addition on the morphology, electrochemical behavior, and mechanical properties of Al–Si coatings were investigated, along with the Mg-content optimization of the coating layer. Adding Mg promoted the formation of finely distributed eutectic intermetallic phases, such as Al/Mg2Si and the primary Mg2Si phase. Notably, the Mg2Si phase coarsened significantly when ≥15 wt.% of Mg was added. In addition, an Al3Mg2 intermetallic compound was observed in coating layers containing >20 wt.% of Mg, reducing the adhesion of the coating layers. Samples containing 5–10 wt.% of Mg exhibited excellent corrosion resistance (owing to a uniform distribution of the fine eutectic Al/Mg2Si phase and the formation of stable corrosion products), whereas those containing 20 wt.% of Mg exhibited unremarkable corrosion resistance (owing to the formation of an Al3Mg2 phase that is susceptible to intergranular corrosion).

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Kochmańska, Agnieszka, and Paweł Kochmański. "Structure of Intermetallic Al–Si Coating on Inconel 617." Materials Science Forum 782 (April 2014): 594–97. http://dx.doi.org/10.4028/www.scientific.net/msf.782.594.

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Nickel superalloy was coated by aluminide coatings by the slurry method. The slurry as active mixture containing aluminium and silicon powders, an activator and a binder. The coating were obtained by annealed in argon atmosphere. The structure of these coatings is two zonal and depends on time and temperature of producing. The phase composition was determined using following techniques: scanning electron microscopy (SEM) equipped with Xray microanalysis (EDS) combined with electron backscatter diffraction (EBSD) and Xray diffraction (XRD).

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Long, Haiyang, Wei Hao, Rucheng Ma, Yongliang Gui, Chunyan Song, Tieyu Qin, and Xuefeng Zhang. "Effect of Temperature and Load on Tribological Behavior in Laser-Cladded FeCrSiNiCoC Coatings." Materials 16, no. 8 (April 21, 2023): 3263. http://dx.doi.org/10.3390/ma16083263.

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The FeCrSiNiCoC coatings with fine macroscopic morphology and uniform microstructure were made on 1Cr11Ni heat resistant steel substrate by a laser-based cladding technique. The coating consists of dendritic γ-Fe and eutectic Fe-Cr intermetallic with an average microhardness of 467 HV0.5 ± 22.6 HV0.5. At the load of 200 N, the average friction coefficient of the coating dropped as temperature increased, while the wear rate decreased and then increased. The wear mechanism of the coating changed from abrasive wear, adhesive wear and oxidative wear to oxidative wear and three-body wear. Apart from an elevation in wear rate with increasing load, the mean friction coefficient of the coating hardly changed at 500 °C. Due to the coating’s transition from adhesive wear and oxidative wear to three-body wear and abrasive wear, the underlying wear mechanism also shifted.

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Liang, Tian Quan, Xian Fang Yang, Yi Li Wang, and Cui Hua Zhao. "Characterization and Oxidation Behavior of Iron-Based Coatings Prepared by Supersonic Arc Spraying at 800°C." Applied Mechanics and Materials 697 (November 2014): 90–94. http://dx.doi.org/10.4028/www.scientific.net/amm.697.90.

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The characterization in microstructure, morphology and oxidation behavior of three iron-based coatings by Supersonic Arc Spraying (HVAS), were investigated by XRD, FESEM, EDS and thermal exposure in furnace in this paper. It is indicated that the three coatings are typical layer and compact structure. The coatings are composed of Fe (s.s) phase and kinds of ferric oxides, chrome carbides and/ or intermetallic phase distributing along the interface of lamellar layers. More Cr and Ti, Al elements can alternate the diameter and morphologies of the holes, resulting from the formation of oxides, carbides and intermetallic phase. The results indicate that SXTiAlC coating shows the most excellent oxidation resistance with 2.70 mg·cm-2 in mass gain, while that are 88.08 mg·cm-2 and 16.64 mg·cm-2 after 100 h thermal exposure at 800°C for LX88A and SXHCrA coatings, respectively. The oxidation behavior is discussed.

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Zagula-Yavorska, Maryana. "Oxidation Behavior of Non-Modified and Rhodium- or Palladium-Modified Aluminide Coatings Deposited on CMSX-4 Superalloy." Metals 8, no. 8 (August 6, 2018): 613. http://dx.doi.org/10.3390/met8080613.

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Rhodium-modified as well as palladium-modified and non-modified aluminide coatings on CMSX-4 Ni-based superalloy were oxidized in air atmosphere at 1100 °C. Uncoated substrate of CMSX-4 superalloy was also oxidized. The microstructure of coatings before oxidation consists of two layers: an additive and an interdiffusion one. The NiAl intermetallic phase was found in the microstructure of non-modified coatings, while the (Ni,Rh)Al intermetallic phase was observed in the microstructure of rhodium-modified aluminide coatings before oxidation. The (Ni,Pd)Al phase of palladium-modified aluminide coatings in the additive layer was observed before oxidation. The microstructure of the oxidized non-modified coatings consists of the γ’-Ni3Al phase. The oxide layer (10 μm thick) consists of the NiAl2O4 phase and porous Ni-rich oxide. The oxide layers (5 μm thick) formed on the surface of rhodium or palladium-modified coatings consist of the α-Al2O3 phase and the top layer of the NiAl2O4 phase. Al-depleted (30 at. %) β-NiAl grains besides the γ’-Ni3Al phase were found in the rhodium-modified coating, while only the γ’-Ni3Al phase region was revealed in the palladium-modified coating, Rhodium-modified coatings with small rhodium content (0.5 μm rhodium layer thick) can be an alternative for palladium-modified ones with bigger palladium content (3 μm thick palladium layer).

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Vardanyan, E. L., V. V. Budilov, I. I. Yagafarov, and K. N. Ramazanov. "Producing of Ti_x-Al_y Intermetallic Coatings on the Surface of Pre-Nitriding Punching Tools." Applied Mechanics and Materials 799-800 (October 2015): 418–22. http://dx.doi.org/10.4028/www.scientific.net/amm.799-800.418.

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The problem of punching tools resistance increasing is investigated. Methods for intermetallic coatings synthesis are investigated. Mathematical model of vacuum ion-plasma deposition process allowing predicting coatings composition basing on intermetallic system Ti-Al was developed. Experimental verification confirmed the adequacy of the computer model. The technology hardening punching tools with wear-resistant coatings deposition based on intermetallic Ti-Al system on pre-nitriding surface in vacuum was developed. Production tests of the hardened punching tools were carried out.

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Zhao, Zhi Long, Jian Long Wang, and Yan Liu. "The Investigation of Hot-Dip Aluminum and Micro-Arc Oxidation Multilayer Coating on 080A15 Steel." Advanced Materials Research 139-141 (October 2010): 406–9. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.406.

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By the combined process of hot-dip aluminum and micro-arc oxidation, multilayer ceramic coatings were obtained on the surface of commercial 080A15 steel plates. The microstructures and chemical elements of the coatings were investigated by means of scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS), respectively. The results show that the conversion coating on the surface of 080A15 steel plate is mainly composed of three layers, they are the outer layer of alumina ceramic coating, the middle layer of pure aluminum, and the inner layer of FeAl intermetallic compound. The FeAl intermetallic compound layer appears as branch-like to grow into the steel substrate. The alumina ceramic layer is a porous structure attached on the pure aluminum layer. The distribution of composition elements on the interface between the each layer is gradient transition, which is one of metallurgical adhesive characteristics.

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Jin, Guo, Qing Fen Li, Bin Shi Xu, Hai Dou Wang, and Shi Cheng Wei. "Research on the Microstructure and Micro-Mechanics Properties of NiAl Intermetallic Coatings." Key Engineering Materials 324-325 (November 2006): 675–78. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.675.

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A new thermal spraying technique, electro-thermal explosion directional spraying (EEDS), was used to prepare NiAl intermetallic coatings. The microstructure, elements distribution and phase structures were determined by means of SEM, EDAX and X-Ray diffraction, respectively. Micro-mechanics properties were tested by using nano-indentation tester. The wear resistance of the coating was also investigated. Results showed that NiAl coating was characterized by compact construction. The main phase of the coating was Ni-Al and the content of oxide was little. The obvious elements diffusion showed that the bond between the coating and the substrate was metallurgical one. The nano-hardness and the modulus were 7.6 GPa and 218.8 GPa, respectively. The coatings processed good wear resistance and the main wear failure mechanism was the micro-plowing.

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Maev, Roman Gr, Jimi Tjong, Eugene Leshchinsky, Mircea Pantea, and Volf Leshchynsky. "Cold-Sprayed Multilayer Thermal Barrier–Catalytic Coatings for Engine Pistons: Coatings Design and Properties." Coatings 12, no. 9 (September 13, 2022): 1332. http://dx.doi.org/10.3390/coatings12091332.

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Yttrium-stabilized zirconia thermal barrier coatings (TBCs) of combustion chambers and piston crowns are used most frequently to increase the chamber temperature and the internal combustion engine efficiency. The development of multilayer metal matrix composite coating is of great importance to diminish the ceramic thermal barrier coating’s brittleness and susceptibility to degradation providing the similar thermal insulation. Our group is developing multilayer TBCs based on intermetallic (Fe-Al) compounds combined with alternating zirconia-based layers made by low-pressure cold spraying (LPCS) and sintering. The Fe-Al intermetallic phase was synthesized during reaction sintering of stainless steel and Al particles in the powder layer previously obtained by cold spraying. A double-nozzle low-pressure cold-spraying gun was used to deposit two layers (stainless steel and Al-YSZ) per one track. The effect of the breaking of the brittle ZrO2 particles due to impingement with the substrate results in the formation of a relatively homogeneous structure with ZrO2 particle size of 3–10 μm. Cold-spray deposition of additional Cu-Ni-Graphene catalytic layers on the TBCs is developed to improve performance and emissions of engines. The microstructure, thermal conductivity, thermal shock behavior and microhardness of TBCs were examined and discussed.

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Mokgalaka, Mokgadi Nomsa, Sisa Lesley Pityana, Patricia Abimbola Idowu Popoola, and Tebogo Mathebula. "NiTi Intermetallic Surface Coatings by Laser Metal Deposition for Improving Wear Properties of Ti-6Al-4V Substrates." Advances in Materials Science and Engineering 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/363917.

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The NiTi intermetallic possesses a number of good properties, such as high wear, oxidation, and corrosion resistance. This paper focuses on the deposition of NiTi intermetallic coatings on Ti6Al4V substrate by laser melting of Ti and Ni elemental powder mixtures. The effect of varying the Ti content in the NiTi composition on the microstructure and wear properties of the coatings was investigated. The microstructure of the NiTi intermetallic coatings were characterized by the scanning electron microscope (SEM) equipped with Energy Dispersive Spectroscope (EDS). The wear properties of the coatings were performed under accelerated dry sliding wear tests. The results obtained from the SEM/EDS analysis; show that the coatings consist of Ni and Ti elements from the feedstock, and the NiTi, NiTi2and NiTi3, intermetallic phases. Dry sliding wear analysis revealed that there is correlation between the hardness and the wear rate. The coatings displayed significant improvement in wear resistance up to 80% compared to the substrate.

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Savkovs, Konstantins, Margarita Urbaha, and Viktors Feofanovs. "Determining High-Temperature Oxidation Resistance of (TI-Al-X-N) Based Coatings for Titanium Alloys." Solid State Phenomena 320 (June 30, 2021): 66–71. http://dx.doi.org/10.4028/www.scientific.net/ssp.320.66.

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Basic titanium alloys are successfully used in modern aviation GTE (gas turbine engine). They are used for parts of a compressor and partly in low pressure part of turbine (intermetallic Ti-Al alloys) due to their high specific strength and at the same time low density, high corrosion resistance but can be used only up to 700 °C. The paper deals with the results of heat resistance testing at 750 °C of Ti-Al-(X)+N based thin ion-plasm multilayers coatings, with different priority of monolayers- intermetallic, conglomerate or nitride for gas turbine engine (GTE) blades from titanium alloys. All coatings showed high resistance during the test, with a maximum efficiency 42.8 of coating with a priority of conglomerate after 30 hours of testing.

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Ambriško, Ľubomír, and Ladislav Pešek. "Local Mechanical Properties of Zinc-Iron Coated Steel Sheets by Depth-Sensing Indentation." Key Engineering Materials 784 (October 2018): 153–58. http://dx.doi.org/10.4028/www.scientific.net/kem.784.153.

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Depth-sensing indentation (DSI) is used in this work to determine the change of local mechanical properties by annealing of hot-dip galvanized IF steel sheets. The influence of annealing conditions (temperature and time) on: (i) coating composition; (ii) local mechanical properties and (iii) roughness of the coating surface was quantified. Annealing of steel samples (Ti-IF steel and Ti-Nb-P-IF steel alloyed with phosphorus) was performed with different holding times (10, 60, and 300 s) by both temperatures 450 and 550 °C. The zinc in coating transformed during annealing to the intermetallic phases ZnxFey. Annealed Zn-Fe coatings, wherein the iron concentration falls towards the surface, consist of different intermetallic phases.

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Hou, Shi Xiang, Zong De Liu, Dong Yu Liu, and Li Ping Zhao. "Spraying Distance and Oxidation Resistance of Electrothermal Explosion Sprayed MoSi₂-Based Coatings." Advanced Materials Research 105-106 (April 2010): 409–12. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.409.

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Intermetallic compound MoSi2 is useful for protective coatings against high-temperature oxidation. In this study, MoSi2-based coatings were prepared using electrothermal explosion ultra-high speed spraying methods. The spraying distance from electric exploding chamber to substrate are 5mm, 10mm, 15mm and 20mm, respectively. The microstructures, phase structures and hardness of the coatings were investigated by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Vickers hardness tester, respectively. The result indicates that MoSi2 primary phase is synthesized. When spraying distance is 10mm, the coatings have density microstructure, submicron grains and high microhardness. The bonding of coating-substrate is metallurgical. The oxidation resistance of Mo-Si-Al coating is higher than that of Mo-Si coating.

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Чесноков, А. Е., А. В. Смирнов, В. О. Дроздов, and К. А. Скороход. "Формирование интерметаллического покрытия Ni-=SUB=-3-=/SUB=-Al холодным газодинамическим напылением механически обработанной в планетарной мельнице порошковой смеси Ni-Al." Письма в журнал технической физики 49, no. 6 (2023): 7. http://dx.doi.org/10.21883/pjtf.2023.06.54808.19421.

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The features of the formation of an intermetallic Ni3Al coating by cold spraying of a Ni–Al powder mixture mechanically treatment in a planetary mill and prepared in a V-shaped mixer are presented. It is shown that the powder deposition efficiency is 1.5 times higher when coatings are obtained from a mechanically treated powder mixture of Ni and Al components. Subsequent high-temperature treatment in the furnace chamber creates a condition for the formation of an intermetallic compound of the Ni-Al system of various stoichiometric proportions.

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Химухин, Сергей, Sergey Himuhin, Виктор Гостищев, Viktor Gostischev, Анастасия Меднева, Anastasiya Medneva, Хосен Ри, Hosen Ri, Эрнст Ри, and Ernst Ri. "INTERMETALLIC COATINGS AFTER HEAT RESISTANCE TEST." Bulletin of Bryansk state technical university 2017, no. 2 (June 30, 2017): 125–33. http://dx.doi.org/10.12737/article_59353e29bc12a3.69771142.

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49

Dziková, Juliána, Stanislava Fintová, Daniel Kajánek, Zuzana Florková, Jaromír Wasserbauer, and Pavel Doležal. "Characterization and Corrosion Properties of Fluoride Conversion Coating Prepared on AZ31 Magnesium Alloy." Coatings 11, no. 6 (June 2, 2021): 675. http://dx.doi.org/10.3390/coatings11060675.

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Abstract:

Wrought AZ31 magnesium alloy was used as the experimental material for fluoride conversion coating preparation in Na[BF4] molten salt. Two coating temperatures, 430 °C and 450 °C, and three coating times, 0.5, 2, and 8 h, were used for the coating preparation. A scanning electron microscope and energy-dispersive X-ray spectroscopy were used for an investigation of the surface morphology and the cross-sections of the prepared coatings including chemical composition determination. The corrosion resistance of the prepared specimens was investigated in terms of the potentiodynamic tests, electrochemical impedance spectroscopy and immersion tests in the environment of simulated body fluids at 37 ± 2 °C. The increase in the coating temperature and coating time resulted in higher coatings thicknesses and better corrosion resistance. Higher coating temperature was accompanied by smaller defects uniformly distributed on the coating surface. The defects were most probably created due to the reaction of the AlxMny intermetallic phase with Na[BF4] molten salt and/or with the product of its decomposition, BF3 compound, resulting in the creation of soluble Na3[AlF6] and AlF3 compounds, which were removed from the coating during the removal of the secondary Na[MgF3] layer. The negative influence of the AlxMny intermetallic phase was correlated to the particle size and thus the size of created defects.

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Lu, Dongzhu, Yanliang Huang, Jizhou Duan, and Baorong Hou. "A Zinc-Rich Coating Fabricated on a Magnesium Alloy by Oxide Reduction." Coatings 9, no. 4 (April 25, 2019): 278. http://dx.doi.org/10.3390/coatings9040278.

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The corrosion resistance of magnesium alloys could be enhanced by covering metallic coatings on the surface. The zinc-rich coating is one of these metallic coatings. To fabricate a zinc-rich coating on magnesium alloys, the substrate should be pretreated carefully, and a protective atmosphere is usually required. In this research, a zinc-rich coating was successfully fabricated on the AZ91D magnesium alloy in air by a diffusion alloying method, with zinc oxide as the zinc source. At the same time, the pretreatment of the magnesium alloy matrix was greatly simplified. The as-diffusion-alloyed zinc-rich intermetallic layer was investigated, utilizing SEM, EDS, and XRD, respectively. It is inferred that zinc oxide was reduced into Zn atoms by the active Mg atoms, and the Mg atoms were coming from the magnesium alloy matrix. Then the Zn atoms passed through the oxide film and formed an intermetallic layer on the magnesium alloy surface. Thus, taking advantage of the activity of Mg atoms, magnesium alloys could be surface alloyed with oxides.

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Journal articles on the topic 'Intermetallic Coatings'

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