Journal articles: 'Aluminide Coating'

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Hua, Yin Qun, Zhen Rong, Kang Min Chen, Yun Xia Ye, Wen Hui Wu, and Rui Fang Chen. "Effect of Y₂O₃ on Microstructure and Oxidation Behavior of Aluminide Coating on Ni-Based Superalloy." Advanced Materials Research 1095 (March 2015): 603–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1095.603.

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The oxidation behavior of Ni-based superalloy GH586 which is treated by pack-cementation aluminizing was investigated. Scanning electron microscope and X-ray diffraction were used to analyze the microstructure of aluminide coatings and the surface morphologies of the oxide scales. Results show that the main phase of the aluminide coatings was NiAl. The aluminide coating can be formed at lower temperature due to the addition of rare earth oxide in the mixture powders. The thickness of aluminide coating at 900°C was about 110μm, and another aluminide coating with rare earth oxide Y2O3 at 800°C was about 38μm. The oxidation kinetics of aluminized specimens approximately followed a parabolic oxidation law at 1000°C. The morphology of the oxidation scales was primarily θ-Al2O3 with minor α-Al2O3. The scales of the coatings with rare earth oxide Y2O3 after oxidation was more dense.

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Góral, Marek, Andrzej Nowotnik, and Jan Sieniawski. "The CVD Aluminizing of TiAl Intermetallics." Solid State Phenomena 203-204 (June 2013): 327–30. http://dx.doi.org/10.4028/www.scientific.net/ssp.203-204.327.

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The article presents the first attempt to CVD-aluminise alloys based on an intermetallic phase Ti48Al2Cr2Nb. Moreover, it includes initial results of producing VPA-deposited aluminide coating in industrial environment. Microstructure and phase analyses of the obtained coatings have been conducted. The chemical and phase composition analyses have revealed that the CVD-deposited coating was roughly 8 m thick, and composed of aluminium-rich TiAl phase, whereas the application of VPA method results in a coating which is approximately 18 m thick and consists of three layers made up of TiAl3, TiAl2 i TiAl phases. Both deposition processes were conducted with industrial equipment.

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Hong, Seok Jun, Jae Woong Choi, Gil Ho Hwang, Won Kyu Han, Joon Shik Park, and Sung Goon Kang. "Effect of the Palladium Mid-Layer on the Cyclic Oxidation of Platinum Aluminide Bond Coating." Materials Science Forum 510-511 (March 2006): 1058–61. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.1058.

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Platinum/Palladium modified aluminide coatings prepared by aluminide pack cementation on the nickel base superalloy Inconnel 738. The platinum/palladium modified aluminide coating of cyclic oxidation behavior at 1200°C was investigated by TGA, XRD and SEM/EDS. Platinum/Palladium modified aluminide coatings showed better cyclic oxidation resistance than Platinum modified aluminide coating and palladium modified aluminide coating compared. Pt and Pd alloy played an enough role in alumina stabilization and in delaying the degradation of β-phase.

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McMinn, A., R. Viswanathan, and C. L. Knauf. "Field Evaluation of Gas Turbine Protective Coatings." Journal of Engineering for Gas Turbines and Power 110, no. 1 (January 1, 1988): 142–49. http://dx.doi.org/10.1115/1.3240077.

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The hot corrosion resistance of several protective coatings that had been applied to MAR-M-509 nozzle guide vanes and exposed in a utility gas turbine has been evaluated. The coatings included basic aluminide, rhodium-aluminide, platinum-rhodium-aluminide, and palladium-aluminide diffusion coatings, and cobalt-chromium-aluminum-yttrium (CoCrAlY) and ceramic overlay coatings. A combination of metallographic examination of vane cross sections and energy dispersive X-ray analysis (EDS) was employed in the evaluation. The results showed that none of the coatings was totally resistant to corrosive attack. The CoCrAlY and platinum-rhodium-aluminide coatings exhibited the greatest resistance to hot corrosion. The CoCrAlY coated vanes were, however, susceptible to thermal fatigue cracking. Except for the poor performance of the palladium-aluminide coating, the precious metal aluminides offered the best protection against corrosion. Hot isostatically pressing coatings was not found to be beneficial, and in one case appeared detrimental.

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Kovrov, Vadim, Yuriy Zaikov, Vladimir Tsvetov, Yuriy Shtefanyuk, Vitaliy Pingin, and Matvey Golubev. "Aluminide Coating Application for Protection of Anodic Current-Supplying Pins in Soderberg Electrolytic Сell for Aluminium Production." Materials Science Forum 900 (July 2017): 141–45. http://dx.doi.org/10.4028/www.scientific.net/msf.900.141.

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Anodic current-supplying pins (ACP) made of low-carbon steel corrode intensively due to the sulfur contamination of the carbon-based Soderberg anode and iron sulfides formation in the present aluminium production technology. The aluminide coatings produced by the liquid-phase method followed by the fluoride flux treatment of the steel samples were applied for the ACP protection. The protective layer based on α-Al2O3 and FeAl2O4 was formed on the steel surface in the course of the test run in the industrial Soderberg anode during the aluminium electrolysis. The aluminized ACP wear rates calculated by the linear extrapolation of data obtained during 150 days workout were 4.0 and 5.4 cm/year for the ACP with the aluminide coating and without it, respectively. The current load on the ACP remained almost the same for the aluminized and original uncoated samples with the exception of the initial “heating” period (400-600°C).

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Cheruvu, N. S., K. S. Chan, and G. R. Leverant. "Cyclic Oxidation Behavior of Aluminide, Platinum Modified Aluminide, and MCrAlY Coatings on GTD-111." Journal of Engineering for Gas Turbines and Power 122, no. 1 (October 20, 1999): 50–54. http://dx.doi.org/10.1115/1.483174.

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Cyclic oxidation behavior of aluminide, platinum modified aluminide, and MCrAlY coatings has been investigated at three temperatures. Aluminide and platinum modified coatings were deposited on GTD 111 material using an outward diffusion process. CoCrAlY coating was applied on GTD-111 by Electron Beam Physical Vapor Deposition (EB-PVD). The oxidation behavior of these coatings is characterized by weight change measurements and by the variation of β phase present in the coating. The platinum modified aluminide coating exhibited the highest resistance to oxide scale spallation (weight loss) during cyclic oxidation testing. Metallographic techniques were used to determine the amount of β phase and the aluminum content in a coating as a function of cycles. Cyclic oxidation life of these coatings is discussed in terms of the residual β and aluminum content present in the coating after exposure. These results have been used to calibrate and validate a coating life model (COATLIFE) developed at the Material Center for Combustion Turbines (MCCT). [S0742-4795(00)00801-2]

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Filip, Ryszard, Marek Góral, Marcin Zawadzki, Andrzej Nowotnik, and Maciej Pytel. "The Influence of Long-Term Heat Treatment on Microstructure of Zr-Modified Aluminide Coating Deposited by CVD Method on MAR M200+Hf Nickel Superalloy." Key Engineering Materials 592-593 (November 2013): 469–72. http://dx.doi.org/10.4028/www.scientific.net/kem.592-593.469.

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The article presents the investigation of influence of long-term annealing of Zr modified aluminide coatings on its microstructure. The coatings were deposited by Chemical Vapour Deposition on MAR M200+Hf nickel superalloy. Annealing was carried out in a vacuum furnace at the temperature 1020°C within the period of 12, 16 and 20 hours respectively. The microstructral analysis was carried out using Hitachi S-3400 scanning electron microscope. Phase changes in the aluminide layer were observed, particularly the NiAl phase into Ni3Al. Changes in thickness of individual layers in the coating were observed. Conducted research showed that there is no influence of Zr on structure of the aluminide coating during annealing. The structure changes are similar to observed in simple aluminide coating. The maximum time of heat treatment without significant influence on structure of aluminide coating is 16 hours. After that time the main component of coating is NiAl phase.

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Du, Hailiang, Ning Tan, Li Fan, Jiajie Zhuang, Zhichao Qiu, and Yanhua Lei. "Formation Mechanism of Aluminide Diffusion Coatings on Ti and Ti-6Al-4V Alloy at the Early Stages of Deposition by Pack Cementation." Materials 12, no. 19 (September 23, 2019): 3097. http://dx.doi.org/10.3390/ma12193097.

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The diffusion coatings were deposited on commercially pure Ti and Ti-6Al-4V alloy at up to 1000 °C for up to 10 h using the pack cementation method. The pack powders consisted of 4 wt% Al (Al reservoir) and 4 wt% NH4Cl (activator) which were balanced with Al2O3 (inert filler). The growth kinetics of coatings were gravimetrically measured by a high precision balance. The aluminised specimens were characterised by means of scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). At the early stages of deposition, a TiO2 (rutile) scale, other than aluminide coating, was developed on both materials at <900 °C. As the experimental temperature arose above 900 °C, the rutile layer became unstable and reduced to the low oxidation state of Ti oxides. When the temperature increased to 1000 °C, the TiO2 scale dissociated almost completely and the aluminide coating began to develop. After a triple-layered coating was generated, the coating growth was governed by the outward migration of Ti species from the substrates and obeyed the parabolic law. The coating formed consisted of an outer layer of Al3Ti, a mid-layer of Al2Ti and an inner layer of AlTi. The outer layer of Al3Ti dominated the thickness of the aluminide coating.

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Góral, Marek, Maciej Pytel, Ryszard Filip, and Jan Sieniawski. "The Influence of Turbine Blade Geometry and Process Parameters on the Structure of Zr Modified Aluminide Coatings Deposited by CVD Method on the ZS6K Nickel Superalloy." Solid State Phenomena 197 (February 2013): 58–63. http://dx.doi.org/10.4028/www.scientific.net/ssp.197.58.

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The Zr modified aluminide coatings is an alternative concept for replacing Pt-modified aluminide bondcoat for thermal barrier coatings. In the paper the influence of process parameters on the chemical composition and the thickness of aluminide coatings will be presented. The zirconia-doped aluminide coating was deposited on turbine blades made from ZS6K nickel superalloy during the low-activity CVD process. In recent work the influence of turbine blade geometry on thickness of coating was observed. The thickest coating was observed on the trailing and leading edge on the blade cross-section. In the conducted research, the light and scanning electron microscopy were used as well as the EDS chemical composition microanalysis.

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Zagula-Yavorska, M., and J. Romanowska. "The effect of precious metals in the NiAl coating on the oxidation resistance of the Inconel 713 superalloy." Journal of Mining and Metallurgy, Section B: Metallurgy, no. 00 (2022): 11. http://dx.doi.org/10.2298/jmmb220427011z.

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The rhodium incorporated aluminide coating was produced by the rhodium electroplating (0.5 ?m thick layer) followed by the chemical vapor deposition process on the Inconel 713 superalloy. This coating is composed of the ?-NiAl phase. A part of nickel atoms is replaced by rhodium atoms in the ?-NiAl phase. The plain, rhodium and platinum incorporated aluminide coatings were oxidized at 1100?C under the atmospheric pressure. The oxidation kinetics of the rhodium and platinum incorporated aluminide coatings are similar, but different than oxidation kinetic of the plain coating. The ?-Al2O3 is the main product both in rhodium and platinum modified coatings after 360 h of oxidation. Moreover, the ?-Ni3Al phase, besides the ?-NiAl phase, was identified. The presence of 4 at. % rhodium in the coating provides similar oxidation resistance as the presence of 10-20 at. % platinum. Both rhodium and platinum incorporated aluminide coatings produced by the chemical vapor deposition process offer good oxidation protection of the Inconel 713 superalloy.

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Fan, Dong Wei, Han Soo Kim, Rho Bum Park, and Bruno C. De Cooman. "Aluminide Coating Formation on Hot Press Forming Steels." Materials Science Forum 654-656 (June 2010): 326–29. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.326.

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In the present work, the formation of an aluminide coating prior to Hot Press Forming (HPF) was investigated. It was found that the formation of Fe3Al phases could suppress coating degradation during the HPF process. This new method was studied as a way to simultaneously improve the coating ductility and achieve a good hot corrosion resistance. In this new method, the conventional type1 aluminized coating was transformed into an aluminide coating. This aluminide coating protects the steel from high temperature oxidation and enables its plastic deformation at high temperature. The effect of this new solution on the mechanical properties of HPF steel is reviewed in detail.

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Filip, Ryszard, Maryana Zagula-Yavorska, Maciej Pytel, Jolanta Romanowska, Mateusz Maliniak, and Jan Sieniawski. "The Oxidation Resistance of Nonmodified and Zr-Modified Aluminide Coatings Deposited by the CVD Method." Solid State Phenomena 227 (January 2015): 361–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.361.

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The aim of the present work was to determine the influence of chemical composition of the protective coating on the oxidation resistance of the protected alloy. Zirconium modified and nonmodified aluminide coatings were deposited on the MAR M200 nickel superalloy by the CVD method. The oxidation tests were conducted at 1100°C into 23 hour in the air. The chemical composition (EDS) analysis was performed. The kinetic of oxidation of zirconium modified and nonmodified aluminide coatings was similar. Oxides inclusions called pegs were observed on the surface of oxidized aluminide coating. HfO2 oxide is more stable than Al2O3 oxide, hafnium atoms can replace aluminum atoms in Al2O3 oxides. This phenomena let to stabilize NiAl phase and increase of oxidation resistance of aluminide coating.

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Kochmańska, Agnieszka, and Paweł Kochmański. "Aluminide Protective Coatings Obtained by Slurry Method." Materials Science Forum 782 (April 2014): 590–93. http://dx.doi.org/10.4028/www.scientific.net/msf.782.590.

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The slurry aluminide coatings are produced on the three kind of substrates: hightemperature creep resistant cast steel, titanium alloy and nickel alloy. The slurry as active mixture containing aluminium and silicon powders, an activator and an inorganic binder. The coating were obtained by annealed in air atmosphere. The structure of these coatings is two zonal and depend on the type of substrate and technological parameters of producing.

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Lee, Byeong Woo. "Effect of diffusion coatings on the high temperature properties of nickel-chromium-superalloys." International Journal of Modern Physics B 32, no. 19 (July 18, 2018): 1840056. http://dx.doi.org/10.1142/s0217979218400568.

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The halide-activated pack cementation method was utilized to deposit aluminide or silicide coatings on Inconel 617 and Hastelloy X superalloys. Aluminide and silicide diffusion coatings were formed at 850[Formula: see text]C for 2 h in nitrogen atmosphere, using a pack mixture containing pure aluminum (Al) or silicon (Si) and aluminum oxide (Al2O3) powders with activators of NH4Cl and AlF3. Aluminide-coated alloys showed homogeneous and uniform microstructures. Al diffused into the alloy inwards and aluminide diffusion coatings of [Formula: see text]17 [Formula: see text]m thick were formed inside the alloy. It was shown that the Al coatings played a key role in blocking off the excessive corrosion products at a high temperature for the alloys. The enhanced thermal stability and improved wear resistance were achieved in the aluminide coatings. In contrast to the aluminide coating, the silicide coating played a negative role, unable to provide the protective layer. The microstructural evolution and thermal stability of the aluminide- and silicide-coated alloys have been elucidated.

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Shirvani, K., and S. V. Miraboutalebi. "Cyclic Oxidation Performance of Si-Aluminide/MCrAlY Coating on Ni-Base GTD-111 Superalloy." Materials Science Forum 889 (March 2017): 159–64. http://dx.doi.org/10.4028/www.scientific.net/msf.889.159.

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A slurry aluminising process was utilised to produce duplex Si-modified aluminide MCrAlY coatings for superalloy GTD-111. MCrAlY coating was applied by means of high velocity oxy-fuel (HVOF) metal spray technique. Cyclic oxidation behaviour of the aluminide/MCrAlY coating were compared with plain MCrAlY coating. Oxidation performance of the coated samples was investigated by exposing samples to 1 h cyclic oxidation at 1100 °C. Oxidation test results demonstrate the Si-aluminide/MCrAlY coating exhibited much better oxidation resistance than the the uncoated superalloy due to the superior oxidation resistance of the alumina-silica scale at 1100 °C.

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Li, Chao, Peng Song, Kunlun Chen, Xuan He, Xiao Yu, and Jiansheng Lu. "Destructive Effect of Water Vapour on an In Situ Diffusion Barrier Layer within an Aluminide Coating on IN738 Alloy." Coatings 8, no. 10 (September 21, 2018): 332. http://dx.doi.org/10.3390/coatings8100332.

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High-temperature interdiffusion within a hot-dipped aluminide (Al-10 wt.% Si) coating on an IN738 superalloy was investigated at 1050 °C in air and in air plus water vapour. The resulting morphology of in situ diffusion barrier layer (DBL) within the aluminide coating is affected by oxidizing atmospheres; DBL can effectively retard the interdiffusion of aluminium within the coating. The location of the in situ DBL is governed by the partial pressure of oxygen at different depths from the oxide scales in both atmospheres. Meanwhile, the diffusion fluxes of different elements led to DBLs with different morphologies in the aluminide coating on the Ni-based alloy.

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Xie, Dong Bai, Sheng Long Zhu, Wen Jun Dai, and Fu Hui Wang. "Influence of NiCoCrAlY and Diffusion Aluminide Coating on Oxidation and Hot Corrosion of a Ni-Based Superalloy." Materials Science Forum 546-549 (May 2007): 1739–46. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1739.

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The most common metallic coatings used in today’s gas turbine engines are MCrAlX (where M is Ni and/or Co and X is one or more reactive elements such as Y, Hf, etc.) type overlay coatings. However, overlay coating techniques (plasma and flame spraying or physical vapor deposition) are line-of-site processes, and so, it is possible not to deposit coating on some surface of the complex turbine components. The diffusion aluminide coatings can solve this problem. A NiCoCrAlY and diffusion aluminide coating were prepared on K38G cast alloy by multi-arc ion plating and low pressure chemical vapor deposition (LP-CVD) techniques, respectively. The isothermal oxidation behavior of K38G and the coatings was studied in air at 900 and 1000 oC. Their hot corrosion behaviors in the presence of 75 wt.% Na2SO4+K2SO4 and 75wt.%Na2SO4+NaCl film at 900oC were studied. The results showed that the two kinds coatings exhibited low oxidation rate at 900 and 1000oC and the presence of salt accelerated the oxidation rate. The NiCoCrAlY coating showed the better hot corrosion resistance than the aluminide coating.

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Chan, K. S., N. S. Cheruvu, and G. R. Leverant. "Coating Life Prediction Under Cyclic Oxidation Conditions." Journal of Engineering for Gas Turbines and Power 120, no. 3 (July 1, 1998): 609–14. http://dx.doi.org/10.1115/1.2818189.

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The hot gas path section components of land based turbines require materials with superior mechanical properties and good hot corrosion and oxidation resistance. These components are generally coated with either a diffusion coating (aluminide or platinum aluminide) or with an overlay coating (MCrAlY) to provide additional hot corrosion and/or oxidation protection. These coatings degrade due to inward and outward diffusion of elements during service. Outward diffusion of aluminum results in formation of a protective oxide layer on the surface. When the protective oxide spalls, Aluminum in the coating diffuses out to reform the oxide layer. Accelerated oxidation and failure of coating occur when the Al content in the coating is insufficient to reform a continuous alumina film. This paper describes development of a coating life predictions model that accounts for both oxidation and oxide spallation under thermal mechanical loading as well as diffusion of elements that dictate the end of useful life. Cyclic oxidation data for aluminide and platinum aluminide coatings were generated to determine model constants. Applications of this model for predicting cyclic oxidation life of coated materials are demonstrated. Work is underway to develop additional material data and to qualify the model for determining actual blade and vane coating refurbishment intervals.

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Čelko, Ladislav, Simona Hutařová, Martin Petrenec, Karel Obrtlík, Martina Hrčková, and Tomáš Podrábský. "Microstructural Characterization of Slurry Aluminide Diffusion Coatings." Materials Science Forum 782 (April 2014): 584–89. http://dx.doi.org/10.4028/www.scientific.net/msf.782.584.

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Commercially pure aluminium powder and a mixture of aluminium and silicon powders, both in a liquid amyl acetate-based organic binder, were sprayed onto the surface of Inconel 713LC nickel base superalloy. A two-stage heat treatment process in an argon atmosphere flow was designed and applied to produce nickel aluminide diffusion coatings. Two coating systems composed of different layers with gradual changes in chemical composition and phase quantities were formed. Scanning electron microscope, scanning electron microscope/focused ion beam, both equipped with energy dispersive microanalyzers, were utilized to characterize the microstructure and chemical composition of the coatings.

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Song, Peng, and Jian Sheng Lu. "Effect of Polishing Treatment on Rumpling of Oxide Scales on NiPtAl Coatings with Different Pt-Content." Advanced Materials Research 662 (February 2013): 383–86. http://dx.doi.org/10.4028/www.scientific.net/amr.662.383.

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Pt-modified nickel aluminide coatings have been more widely used for protection of jet-engine components against high-temperature oxidation. The coating rumpling of two Pt-content NiPtAl coatings was studied in this paper during high temperature exposure. The results indicated that the NiPtAl coating grains size made a great contribution to the oxide surface morphologies, especially rumpling. Smaller grain size within high-Pt coating indicated a denser rumpling compared to low-Pt coating due to PtAl2 formation in the earlier coating. The failed local alumina at the ridges was also found on the low-Pt coating after cyclic oxidatioin. It was found that polished treatment resulted a comparatively flat and homogeneous oxide layer compared to as-received coatings. The temperature cycling could promote the aluminide coating rumpling, however, the polished treatment could not completely eliminate the roughening.

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Zagula-Yavorska, Maryana, Jan Sieniawski, and Ryszard Filip. "The Influence of the Chemical Composition of Superalloys on the Oxidation Resistance of Aluminide Coating." Solid State Phenomena 227 (January 2015): 365–68. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.365.

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The aim of the present work was to determine the influence of chemical composition of the coating protected nickel based superalloys Inconel 713 LC, Inconel 625 and CMSX 4 on the oxidation resistance of aluminide coating. Protective aluminide coatings were deposited in the CVD process. The low activity aluminizing at the presence of AlCl3 and H2 was carried out. Cyclic oxidation test for both coated and uncoated superalloys was performed at 1100°C for 1000 h in the air atmosphere. Microstructure of aluminide coatings after oxidation test was investigated by a scanning electron microscopy (SEM) and an energy dispersive spectroscopy (EDS). The best oxidation resistance shows uncoated Inconel 713 LC superalloy. That is due to a relatively high aluminum content in this alloy. The aluminide coating deposited on the surface of Inconel 625 shows the largest oxidation resistance (insignificnt changes of mass for the whole test duration). Excellent oxidation resistance is a result of Al2O3 scale formation.

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HUANG, MIN, YU WANG, MENG-XIAN ZHANG, YAN-QIU HUO, and PENG-JIN GAO. "EFFECT OF MAGNETRON-SPUTTERED Al FILM ON LOW-TEMPERATURE PACK-ALUMINIZING COATING FOR OIL CASING STEEL N80." Surface Review and Letters 21, no. 04 (August 2014): 1450053. http://dx.doi.org/10.1142/s0218625x1450053x.

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Low-temperature aluminizing coating was prepared onto the surface of oil casing steel N 80 with a magnetron-sputtered Al film to improve its corrosion resistance. Results show that magnetron-sputtered Al film is able to form gradient aluminide coating, composed of iron aluminide FeAl 3, Fe 2 Al 5 and Fe 3 Al with different contents of aluminum. Both the density and continuity of iron aluminide layer for oil casing steel N 80 with magnetron-sputtered Al film can be improved. Under the same corrosion condition, aluminized oil casing steel N 80 with a magnetron-sputtered Al film shows an outstanding corrosion resistance than those of original and aluminized ones without magnetron-sputtered Al film. The positive effect of Al film is considered as the concentration change of active Al atom for diffusion to form the aluminizing coating during the pack processing.

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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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Anwer, Zubia, Muhammad Tufail, and Ali Dad Chandio. "Deposition of Aluminide Coatings onto AISI 304L Steel for High Temperature Applications." Materials 15, no. 12 (June 13, 2022): 4184. http://dx.doi.org/10.3390/ma15124184.

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The nickel aluminides are commonly employed as a bond coat material in thermal barrier coating systems for the components of aeroengines operated at very high temperatures. However, their lifetime is limited due to several factors, such as outward diffusion of substrate elements, surface roughness at high temperatures, morphological changes of the oxide layer, etc. For this reason, inter-diffusion migrations were studied in the presence and absence of nickel coating. In addition, a hot corrosion study was also carried out. Thus, on one set of substrates, nickel electrodeposition was carried out, followed by a high activity pack aluminizing process, while another set of substrates were directly aluminized. The microstructural, mechanical, and oxidation properties were examined using different characterization techniques, such as SEM-EDS, optical microscopy, XRD, optical emission spectroscopy, surface roughness (Ra), and adhesion tests. In addition, the variable oxidation temperatures were employed to better understand their influence on the roughness, degree of spallation (DoS), and morphology. The results show that AISI 304L substrates do not respond to aluminizing treatment, i.e., no aluminide coating was formed; rather, a nearly pure aluminum (or alloy) was observed on the substrate. On the contrary, successful formation of an aluminide coating was observed on the nickel-electrodeposited substrates. In particular, a minimum amount of migrations were noted, which is attributed to nickel coating. Moreover, the scratch test at 10 N load revealed neither cracking nor peeling off, thereby indicating good adhesion of the aluminide coating before oxidation. The as-aluminized samples were oxidized between 700 °C to 1100 °C in air for 8 h each. The degree of spallation showed an incremental trend as temperatures increased. Likewise, oxide morphologies showed temperature dependence. On the other hand, average surface roughness (from Ra = 2.3 µm to 5.8 µm) was also increased as temperatures rose. Likewise, the mass gain showed linearity as temperatures increased during oxidation. The hot corrosion responses of electrodeposited-aluminized samples were superior among all specimens. An extensive discussion is presented based on the observations noted above.

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Nicholls, J. R. "Advances in Coating Design for High-Performance Gas Turbines." MRS Bulletin 28, no. 9 (September 2003): 659–70. http://dx.doi.org/10.1557/mrs2003.194.

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AbstractSurface engineering is now a key materials technology in the design of future advanced gas-turbine engines. This article focuses on coating systems for hot-gas-path components, which can vary from low-cost aluminide diffusion coatings to the more exotic, and therefore expensive, thermal-barrier coatings. Available coating systems and their relative benefits are reviewed in terms of performance against manufacturing complexity and cost. Future trends in the design of environmental- and thermal-protection coatings are discussed, including the addition of multiple reactive elements, modified aluminide coatings, diffusion-barrier concepts, the design of “smart” corrosion-resistant coatings, and the development of structurally modified, low-thermal-conductivity thermal-barrier coatings.

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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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Kochmańska, Agnieszka Elżbieta, Aneta Jarlaczyńska, and Jolanta Baranowska. "Formation of Silicide and Silicide-Aluminide Coatings on Molybdenum Alloy during Slurry Cementation Process: Influence of Slurry Volume." Materials 14, no. 22 (November 17, 2021): 6940. http://dx.doi.org/10.3390/ma14226940.

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New slurry cementation method was used to produce silicide and silicide-aluminide protective coatings on molybdenum alloy (TZM). The slurry cementation processes were carried out at a temperature of 1000 °C in different time intervals with the use of varied slurry mass values. The microstructure and thickness of the coatings were studied by means of scanning microscopy. Chemical composition using X-ray microanalysis and phase composition using X-ray diffraction were also investigated. Coating microhardness was determined. The obtained coatings had a multilayer structure. Phases from the Al-Si-Mo system were observed in silicide-aluminide coatings and phases from the Si-Mo system were observed in silicide coatings. The microhardness strongly depended on the phase composition of the coating. It was demonstrated that slurry mass values had an important influence on the morphology and growth kinetics of silicide-aluminide coatings. In the case of a small amount of the slurry, the deficiency of alloying elements occurring during long processes reduces growth kinetics and can lead to void formation in the structure of silicide-aluminide coatings.

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28

Wang, Yu, and Min Huang. "Aluminizing Coating Prepared on Oil Casing Steel N80 by Low-Temperature Pack Cementation." Advanced Materials Research 368-373 (October 2011): 2180–84. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2180.

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Aluminizing has been verified to be an effective way to improve the corrosion resistance of steel due to the formation of continuous Al2O3layer, but traditional aluminizing processing carried out at high temperature can not be used to prepare aluminide layer on the surface of oil casing steel. In this paper, an aluminide coating was prepared on oil casing steel N80 by a low-temperature pack cementation only at 803 K for 2 hours by adding zinc in the pack powder and pre-treatment of N80 substrate by surface mechanical attrition. The phase compostion, microstructure, element distribution and properties of as-aluminized oil casing steel N80 were characterized by means of XRD, SEM, EDS, micro-hardness test and electrochemical corrosion measurements. The results indicate that aluminide coating mainly consists of FeAl3, Fe2Al5 and FeAl. The continuous aluminide coating with an average thickness around 50 μm could be successfully formed on the surface of oil casing steel N80 which shows a good coherence with as-packed substrate. After preparation of aluminide coating, oil casing steel N80 shows a higher microhardness in the range of aluminizing coating than that of the virgin material because of the formation of iron aluminide. The exception noted is that the proposed low-temperature aluminizing processing does not have any damaging impact on the mechanical properties of steel substrates. Moreover, it is concluded that oil casing steel N80 with aluminizing coating shows a better corrosion resistance than that of original N80 by analyzing of electrochemical test results.

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29

Nowotnik, Andrzej, Jan Sieniawski, Marcin Zawadzki, and Marek Góral. "The Effect of Long-Term Annealing on Microstructure of Aluminide Coatings Deposited on MAR M200 Superalloy by CVD Method." Key Engineering Materials 592-593 (November 2013): 477–80. http://dx.doi.org/10.4028/www.scientific.net/kem.592-593.477.

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The paper presents the influence of long-term heat treatment on aluminide coating. The MAR M-200 nickel superalloy was use as base material. The aluminide coating was deposited in low-activity chemical vapour deposition process using Ion Bond BPX Pro 325s device with following parameters: temperature 1040°C, time 12 hours, pressure 150 mbar. The samples (14 mm diameter) were annealed at 1020°C in vacuum for 12, 16 and 20 hours respectively. The XRD phase analysis and SEM microstructural observation with EDS analysis were conducted. The phase composition analysis showed that after deposition the NiAl phase is a main component of the coating. After the 20-hour-long annealing presence of Ni3Al phase in the coating was observed. Changes in structure of coatings and Al content during heat treatment were detected as well. The maximum duration of heat treatment performed for Ni superalloy with aluminide coating without significant changes in coating phase composition and microstructure is 16 hours.

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30

Günen, Ali, and Ömer Ergin. "A Comparative Study on Characterization and High-Temperature Wear Behaviors of Thermochemical Coatings Applied to Cobalt-Based Haynes 25 Superalloys." Coatings 13, no. 7 (July 20, 2023): 1272. http://dx.doi.org/10.3390/coatings13071272.

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This study investigated the characteristic properties of aluminizing, boronizing, and boro-aluminizing coatings grown on Haynes 25 superalloys and their effects on the high-temperature wear behavior. The coating processes were conducted in a controlled atmosphere at 950 °C for 3 h. Characterization studies were performed using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction analysis, nanoindentation testing, and high-temperature wear tests. It was determined that the thickness values of aluminide, boride, and boride–aluminide coatings were 140 ± 1.50 µm, 37.58 ± 2.85 µm, and 14.73 ± 1.71 µm, and their hardness values were 12.23 ± 0.9 GPa, 26.34 ± 2.33 GPa, and 23.46 ± 1.29 GPa, respectively. The hardness of the coatings resulted in reduced wear volume losses both at room temperature and at 500 °C. While the best wear resistance was obtained in the boronized sample at room temperature due to its high hardness, the best wear resistance at 500 °C was obtained in the boro-aluminized sample with the oxidation–reduction effect of Al content and the lubricating effect of B content in the boro-aluminide coating. This indicates that the presence of aluminum in boride layers improves the high-temperature wear resistance of boride coatings. The coated samples underwent abrasive wear at room temperature, whereas at 500 °C, the wear mechanism shifted to an oxidative-assisted adhesive wear mechanism.

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31

Pugacheva, N. B., and P. A. Polyakov. "The effect of boron on the protective properties of aluminide coatings." Diagnostics, Resource and Mechanics of materials and structures, no. 6 (December 2022): 25–34. http://dx.doi.org/10.17804/2410-9908.2022.6.025-034.

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The effect of the formation, microstructure, phase composition, and protective properties of diffusion aluminide coatings alloyed with boron on the EI69 heat-resistant steel and the EI929 nickel alloy is studied. In the course of saturation, boron easily diffuses over the interstices of the B2 crystal lattice of aluminides, thus forming interstitial solid solutions. In this case, the Al content in the coating decreases, thereby implementing the possibility of increasing the plasticity of the coating while maintaining high protective properties. By binding refractory corrosive elements (Mo, W, Nb, etc.) into corrosion-resistant borides, boron increases the overall resistance of the coating in molten Na2SO4 and NaCl salts at 700 °C by an order of magnitude and improves the resistance of the surface to erosion wear. This makes it possible to recommend Al-Si-B coatings to be used for protecting the surface of the turbine blades of supercharging turbochargers and diesel exhaust valves.

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32

HUANG, MIN, YU WANG, and XIAO YONG ZHANG. "ALUMINIZING OIL CASING STEEL N80 BY A LOW-TEMPERATURE PACK PROCESSING MODIFIED WITH ZINC ADDITION." Surface Review and Letters 18, no. 03n04 (June 2011): 141–46. http://dx.doi.org/10.1142/s0218625x11014588.

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Different aluminide coatings were prepared on oil casing steel N80 at a relatively lower temperature of 530°C for 2 h by pack powder modified with different content of zinc (Zn). The cross-sectional microstructure, element distribution and properties of as-aluminized oil casing steel N80 were investigated by SEM, EDS, micro-hardness test and electrochemical corrosion measurement. Results show that aluminide coating with around 50 μm in thickness can be successfully achieved by a low-temperature pack aluminizing processing with the addition of Zn . Zn in the pack powder can enhance the uniformity and continuity of the coating layer, while it has little effect on the thickness of as-packed coating with the increasing content of Zn from 38.8 wt.% to 84.4 wt.%. As the content of Zn is over 58.8 wt.%, two layer coating consisting of pure Zn layer and Fe–Al aluminide layer can be formed on oil casing steel N80 substrate. Furthermore, oil casing steel N80 with aluminizing coating shows a higher microhardness than that of original one except in the depth range of pure Zn layer, but the microhardness of oil casing steel substrate does not decrease after aluminizing which can be inferred that low-temperature aluminizing processing reported here will not bring any damages on the mechanical properties of oil casing steel N80 . Additionally, a lower self-corrosion current density of oil casing steel N80 with aluminizing coating also indicates that low-temperature aluminizing processing is helpful to the corrosion resistance of oil casing steel N80 .

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33

Chan, K. S., N. S. Cheruvu, and G. R. Leverant. "Coating Life Prediction for Combustion Turbine Blades." Journal of Engineering for Gas Turbines and Power 121, no. 3 (July 1, 1999): 484–88. http://dx.doi.org/10.1115/1.2818498.

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A life prediction method for combustion turbine blade coatings has been developed by modeling coating degradation mechanisms including oxidation, spallation, and aluminum loss due to inward diffusion. Using this model, the influence of cycle time on coating life is predicted for GTD-111 coated with an MCrAlY, PtAl, or aluminide coating. The results are used to construct a coating life diagram that depicts failure and safe regions for the coating in a log-log Plot of number of startup cycles versus cycle time. The regime where failure by oxidation, spallation, and inward diffusion dominates is identified and delineated from that dominated by oxidation and inward diffusion only. A procedure for predicting the remaining life of a coating is developed. The utility of the coating life diagram for predicting the failure and useful life of MCrAlY, aluminide, or PtAl coatings on the GTD-111 substrate is illustrated and compared against experimental data.

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34

Romanowska, J., and M. Zagula-Yavorska. "Microstructure and oxidation resistance of Pd+Zr and Pd+Hf co-doped aluminide coatings deposited on Mar-M247 nickel superalloy." Journal of Mining and Metallurgy, Section B: Metallurgy, no. 00 (2023): 21. http://dx.doi.org/10.2298/jmmb221205021r.

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Pd+Zr and Pd+Hf co-doped aluminide coatings were deposited on the Mar-M247 nickel superalloy by the palladium electroplating followed by zirconizing-aluminizing or hafnizing-aluminizing processes. Both coatings consisted of two zones, the outer and the interdiffusion one build of the ?-(Ni,Pd)Al phase. Hafnium and zirconium formed inclusions that precipitated at the border of the zones and close to the surface (only in the Zr+Pd modified coating). Oxidation resistance of the Pd+Zr co-doped aluminide coating was significantly better than the Pd+Hf co-doped one. Hafnium content in the Pd+Hf co-doped coating could exceed the border value.

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35

Agüero, Alina, Vanessa González, and Marcos Gutiérrez. "Long Term Diffusion Studies in Fe Aluminide Coatings Deposited by Slurry Application on Ferritic Steel." Defect and Diffusion Forum 289-292 (April 2009): 243–51. http://dx.doi.org/10.4028/www.scientific.net/ddf.289-292.243.

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Diffusion iron aluminide coatings have shown excellent resistance to high temperature oxidation in air, corrosive atmospheres and steam. A study of the diffusion behaviour of slurry applied diffusion aluminide coatings deposited on ferritic steel have been carried out under a 100% flowing steam atmosphere for up to 50,000 h at 650 °C. The results have shown that initially, the coating forms by outward growth possibly including the dissolution of the steel in molten aluminium. At later stages, during exposure to steam at 650 °C, aluminium diffuses inward and moreover, Fe also diffuses outward resulting in the progressive development of Kirkendall porosity. Results have also indicated that in order to form a pure protective Al2O3 scale the Al wt.% has to be > 4. Below this content Al-Fe mixed oxides develop exhibiting a less protective behaviour.

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36

Bonetti, Ennio, Enrico Gianfranco Campari, Angelo Casagrande, Giuseppe Catania, and Andrea Garzoni. "Damping Behavior of Layered Aluminium and Aluminide Coatings on AISI 316 Austenitic Steel." Coatings 10, no. 9 (September 17, 2020): 888. http://dx.doi.org/10.3390/coatings10090888.

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Several coating configurations on AISI 316 steel were obtained by a hot dipping process followed by isothermal interdiffusion. Six different kind of multilayered specimens were produced and characterized. These coatings, typically employed as bond coat in thermal barrier coating (TBC), can also be effective as vibration reduction elements at intermediate and high temperatures. This preliminary work was focused on the microstructural design and processing effects of the coatings. The damping of the produced specimens was measured up to 450 °C and compared with that of the steel substrate. The most performing coatings contain an Al-Si layer and exhibit a steep damping increase above 200 °C, reasonably due to dislocation movements by plastic straining of soft alloy layer and to the interface sliding between layers with different elastic moduli.

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37

Swadźba, Lucjan, Ginter Nawrat, Boguslaw Mendala, and Marek Goral. "The Influence of Deposition Process on Structure of Platinum-Modifed Aluminide Coatings O Ni-Base Superalloy." Key Engineering Materials 465 (January 2011): 247–50. http://dx.doi.org/10.4028/www.scientific.net/kem.465.247.

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The modern jet engines used in commercial and military aircrafts are characterized by operating temperature in turbine section above 1000oC. The Ni-base superalloy turbine blades and vanes working in high temperature in very aggressive environment require using of protective coatings. The aluminide coatings are widely used to protect this engine parts. The pack cementation, out of pack and chemical vapour deposition (CVD) technologies are usually used to produce this type of coating. The aluminide coatings can be modified by platinum or other elements. The Pt-modified aluminide coatings are characterized by better oxidation and corrosion resistance in comparison with conventional aluminide coatings and can be used as a bond coat for Thermal Barrier Coatings deposited by EB-PVD technology. In present study the influence of deposition technology and their’s parameters on structure and chemical composition of Pt-aluminide coatings are presented. The base material for coatings was a Inconel 738 Ni-base superalloy. The first step of coatings production were Pt electroplating with different thickness of platinum layer. The second step of coating production was aluminising process. The aluminide coatings were produced by pack cementation and out of pack technologies. Additional the influence of heat treatment of base alloy with coatings was investigated. The structure of all deposited coatings was observed by scanning electron microscopy and the chemical and phase composition of coatings were investigated by EDS and XRD methods. The observed coatings were characterized by two types of structure: first based on NiAlPt phase obtained on thin Pt layer and the second with additional presence of PtAl2 phase on the thick Pt layer.

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38

Erturk, Umutcan, and Bilge Imer. "A Comparative Analysis of Ternary Element Addition on Corrosion Behavior of Aluminide Coatings in Harsh Environmental Conditions." Corrosion 77, no. 12 (November 3, 2021): 1365–73. http://dx.doi.org/10.5006/3855.

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Increasing hot corrosion durability of aluminide coatings is important to extend the lifetime of turbine blades. The addition of hafnium, yttrium, zirconium, chromium, platinum, and cobalt improves the performance of aluminide coating by increasing oxide adherence and selective oxide formation rate. In this research, the effect of adding ternary elements (Y, Cr, Y/Cr, Zr, and Hf) on type-1 hot corrosion behavior of aluminide coatings was investigated by an accelerated isothermal corrosion test at 900°C for up to 400 h. To simulate harsh environmental conditions, Na2SO4- and V2O5-containing solutions were applied to the substrate surface. Subsequently, for 1 h, 50 h, 100 h, 200 h, and 400 h exposure times, the oxide layer thicknesses, spallation time, coating layer depletion time, and elemental analysis of each set were analyzed and their performances compared.

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39

Zagula-Yavorska, Maryana, Jolanta Romanowska, Jan Sieniawski, and Małgorzata Wierzbińska. "Hafnium Modified Aluminide Coatings Obtained by the CVD and PVD Methods." Solid State Phenomena 227 (January 2015): 353–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.353.

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Zirconium, hafnium or platinum modification of NiAl phase increases the oxidation resistance of diffusion aluminide coatings. Small hafnium addition to aluminide coatings decreases the oxidation rate of nickel superalloys at 1100 °C.The paper presents comparison of structures of hafnium modified aluminide coatings deposited in two different ways on pure nickel. In the first way double layers of hafnium 3 μm thick and aluminum 3 μm thick were deposited by the EB-PVD on the nickel substrate. The double layers were subjected to diffusion treatment at 1050 °C for 6 h and 20 h. In the second method, a hafnium layer was deposited by the EB-PVD method, whereas aluminum was deposited by the CVD method. The obtained coatings were examined by the use of an optical microscope (microstructure and coating thickness) and a scanning electron microscope (chemical composition on the cross-section of the modified aluminide coating). Microstructures and phase compositions of coatings obtained by different methods differ significantly. Diffusion treatment for 6 h leads into formation of the Ni5Hf phase. The elongation of the diffusion time from 6 to 20 h decrease the volume fraction of the Ni5Hf phase. An aluminide coating deposited by the CVD method at 1050 °C at the nickel substrate with prior hafnium layer (3 μm thick) has a triple zone structure. An outer zone consists of the NiAl phase, a middle zone consists of the Ni3Al phase, and the Ni(Al) phase forms an inner zone, close to the substrate. An NiHf intermetallic phase is between the outer and the middle zone, whereas Ni3Hf is between the inner zone and the substrate.

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40

Kukla, Dominik, Mateusz Kopec, Zbigniew L. Kowalewski, Denis J. Politis, Stanisław Jóźwiak, and Cezary Senderowski. "Thermal Barrier Stability and Wear Behavior of CVD Deposited Aluminide Coatings for MAR 247 Nickel Superalloy." Materials 13, no. 17 (September 1, 2020): 3863. http://dx.doi.org/10.3390/ma13173863.

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In this paper, aluminide coatings of various thicknesses and microstructural uniformity obtained using chemical vapor deposition (CVD) were studied in detail. The optimized CVD process parameters of 1040 °C for 12 h in a protective hydrogen atmosphere enabled the production of high density and porosity-free aluminide coatings. These coatings were characterized by beneficial mechanical features including thermal stability, wear resistance and good adhesion strength to MAR 247 nickel superalloy substrate. The microstructure of the coating was characterized through scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Mechanical properties and wear resistance of aluminide coatings were examined using microhardness, scratch test and standardized wear tests, respectively. Intermetallic phases from the Ni-Al system at specific thicknesses (20–30 µm), and the chemical and phase composition were successfully evaluated at optimized CVD process parameters. The optimization of the CVD process was verified to offer high performance coating properties including improved heat, adhesion and abrasion resistance.

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41

Romanowska, Jolanta, Maryana Zagula-Yavorska, and Łukasz Kolek. "Oxidation Resistance of Modified Aluminide Coatings." MATEC Web of Conferences 253 (2019): 03006. http://dx.doi.org/10.1051/matecconf/201925303006.

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The application of protective aluminide coatings is an effective way to increase the oxidation resistance of the treated parts and prolongs their lifetime. The addition of small amount of noble metals (platinum or palladium) or reactive elements such as: hafnium, zirconium, yttrium and cerium has a beneficial effect on oxidation behavior. This beneficial effect includes an improvement of adhesion of alumina scales and reduction of oxide scale growth rate. Platinum and hafnium or zirconium modified aluminide coating were deposited on pure nickel using the electroplating and CVD methods. The coatings consisted of two layers: an outer, β-NiAl phase and the interdiffusion γ’-Ni3Al phase. Palladium dissolved in the whole coating, whereas hafnium and zirconium formed inclusions on the border of the layers. Samples were subjected to cyclic oxidation test at 1100 °C for 200h. Oxidation resistance of the palladium, Hf+Pd and Zr+Pd modified coatings deposited on pure nickel does not differ significantly, but is better than the oxidation resistance of the non-modified one.

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42

Kochmańska, Agnieszka E. "Microstructure of Al-Si Slurry Coatings on Austenitic High-Temperature Creep Resisting Cast Steel." Advances in Materials Science and Engineering 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/5473079.

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This paper presents the results of microstructural examinations on slurry aluminide coatings using scanning electron microscopy, X-ray microanalysis, and X-ray diffraction. Aluminide coatings were produced in air atmosphere on austenitic high-temperature creep resisting cast steel. The function of aluminide coatings is the protection of the equipment components against the high-temperature corrosion in a carburising atmosphere under thermal shock conditions. The obtained coatings had a multilayered structure composed of intermetallic compounds. The composition of newly developed slurry was powders of aluminium and silicon; NaCl, KCl, and NaF halide salts; and a water solution of a soluble glass as an inorganic binder. The application of the inorganic binder in the slurry allowed to produce the coatings in one single step without additional annealing at an intermediate temperature as it is when applied organic binder. The coatings were formed on both: the ground surface and on the raw cast surface. The main technological parameters were temperature (732–1068°C) and time of annealing (3.3–11.7 h) and the Al/Si ratio (4–14) in the slurry. The rotatable design was used to evaluate the effect of the production parameters on the coatings thickness. The correlation between the technological parameters and the coating structure was determined.

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43

Shirvani, K., and Amir Firouzi. "Aluminide Coating Formation on Internal Passages of GTD-111 Superalloy by Slurry Technique." Materials Science Forum 595-598 (September 2008): 185–90. http://dx.doi.org/10.4028/www.scientific.net/msf.595-598.185.

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The diffusion aluminide coatings are widely used in the air-cooling passages to protect their surfaces against high temperature corrosion. In this study plain and Si-modified aluminide coatings were applied by slurry technique on internal surfaces of Ni-base GTD-111 superalloy cylindrical specimens derived from a gas turbine air-cooled blade. The slurries containing Al or Al plus Si powders were applied on internal surfaces by injection method. Then, the samples were heated to high temperature (800-1000°C) to form the coatings. Optical, SEM-EDS, and XRD were utilized for characterizing microstructures and phase compositions of the coatings. The thicknesses of applied coatings on internal surfaces were in the range of 30-50 μm that meets specifications for diffusion coatings in such application (i.e. 25-756m). The examinations demonstrated that both coating types were contained β-NiAl phase as the matrix. The uniformities of coatings applied on different surface positions of passageway were determined. In addition, the effects of time and temperature of coating process as well as mass of dried slurry on the coating thickness were also discussed.

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44

Fan, Qixiang, Haojun Yu, Tiegang Wang, and Yanmei Liu. "Microstructure and Oxidation Resistance of a Si Doped Platinum Modified Aluminide Coating Deposited on a Single Crystal Superalloy." Coatings 8, no. 8 (July 27, 2018): 264. http://dx.doi.org/10.3390/coatings8080264.

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A Si doped Pt modified aluminide coating was prepared by electroplating and the chemical vapour deposition method. The microstructure and oxidation resistance of the coating were studied, with a single Pt modified aluminide coating as a reference. The results showed that the Si doped Pt modified aluminide coating consisted of singular β-(Ni, Pt)Al phase, and no PtAl2 phase was detected, which might be due to the fact that the addition of Si retarded the formation of PtAl2 phase in the outer layer. Si was dissolved in the β-(Ni, Pt)Al phase in the outer layer and might form silicide with refractory elements in the inter-diffusion zone. The Si doped Pt modified aluminide coating possesses a better oxidation resistance than the Pt modified aluminide coating since Si could promote the formation of α-Al2O3 and inhibit the diffusion of the refractory elements, reducing the formation of detrimental volatile phase.

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45

Choudhary, R. K., V. Kain, and R. C. Hubli. "Formation of alumina-aluminide coatings on ferritic-martensitic T91 steel." Journal of Mining and Metallurgy, Section B: Metallurgy 50, no. 2 (2014): 165–70. http://dx.doi.org/10.2298/jmmb140724022c.

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In this work, alumina-aluminide coatings were formed on ferritic-martensitic T91 steel substrate. First, coatings of aluminum were deposited electrochemically on T91 steel in a room temperature AlCl3-1-ethyl-3-methyl imidazolium chloride ionic liquid, then the obtained coating was subjected to a two stage heat treatment procedure consisting of prolonged heat treatment of the sample in vacuum at 300 ?C followed by oxidative heat treatment in air at 650 ?C for 16 hours. X-ray diffraction measurement of the oxidatively heat treated samples indicated formation of Fe-Al and Cr-Al intermetallics and presence of amorphous alumina. Energy dispersive X-ray spectroscopy measurement confirmed 50 wt- % O in the oxidized coating. Microscratch adhesion test conducted on alumina-aluminide coating formed on T91 steel substrate showed no major adhesive detachment up to 20 N loads. However, adhesive failure was observed at a few discrete points on the coating along the scratch track.

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46

Góral, Marek, Maciej Pytel, Ryszard Filip, and Andrzej Nowotnik. "The Microstructure of Hafnium Modified Aluminide Coatings Deposited by CVD Method." Materials Science Forum 844 (March 2016): 172–76. http://dx.doi.org/10.4028/www.scientific.net/msf.844.172.

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The paper presents results of microstructural analysis of Hf-modified aluminide coatings. The coating was obtained using chemical vapour deposition (CVD) method at 1040°C using BPX-Pro 325 S equipment (Iond Bond). The deposition process time was 960 mintutes. The IN-718, IN-100 as well as CMSX-4 single-crystal nickel superalloys were the substrate material. The observation of coating was carried out using scanning electron microscopy. Chemical composition was analyzed using EDS method. The results showed that hafnium accumulates mainly on diffusion/additive layer interface and forms a „chain” of small precipitations. Hafnium was found in the additive NiAl layer of aluminide coating deposited on IN-100 superalloy. Its amount did not exceed 0.3 at %.

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47

Kochmańska, A. E. "Aluminide coatings on Inconel 617 obtained by slurry method with inorganic binder." Journal of Achievements in Materials and Manufacturing Engineering 2, no. 85 (December 1, 2017): 49–55. http://dx.doi.org/10.5604/01.3001.0010.8034.

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Purpose: The aim of this study was to manufacture and examine the structure of aluminide coatings formed on Ni-based super alloy Inconel 617 in an argon atmosphere. Design/methodology/approach: The coatings were produced by the slurry method at temperatures from 900 to 1100°C and times from 2 to 6 hours. The newly-developed slurry composition was: powders of aluminium and silicon; NaCl, KCl, NaF halide salts as an activator and a water solution of a soluble glass as an inorganic binder. The microstructure (SEM), chemical composition (EDS) and phase composition (XRD) of the coatings were determined. Additionally the correlation between the technological parameters and the coating thickness was analysed. Findings: Slurry aluminide coatings with newly-developed composition have been successfully produced. The obtained coatings had a multi-zone structure depending on manufacturing parameters. Research limitations/implications: The next stage of this research will be to determine the performance of the coatings under high temperature cyclic oxidation. Optimization of the production parameters will therefore be possible after oxidation and cyclic oxidation tests. Practical implications: The slurry method is economical due to low consumption of powder material. Another advantage of the applied slurry composition is the possibility of forming protective coatings on other substrates. Originality/value: The use of the inorganic binder in the slurry allowed to produce the coatings in one single step without additional annealing at an intermediate temperature as it is when applied organic binder. The grain size of aluminium and silicon powders was less than usually used. The applied activator dissolved the passive layers present on the surface both of the aluminum powder and of the nickel alloy and accelerated the reactions that occur during coating formation.

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48

Moosa, Ahmed, Jalil Karim Ahmed, and Ali Hoobi. "Corrosion Properties of Inconel Alloy 600 Coated by Simultaneous Aluminizing-Chromizing Process." Materials Science Forum 546-549 (May 2007): 1763–68. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1763.

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In this work Inconel 600 alloy was coated with two different types of coatings, Crmodified aluminide coating and Y- doped chromium modified aluminide coating . Diffusion coating was carried at 1050 oC for 8 hrs under Ar atmosphere by single step aluminizing- chromizing process and by single step aluminizing- chromizing- yttriumizing process. The cyclic hot corrosion tests of IN 600 and its coated systems deposited with 2 mg / cm2 NaCl / Na2SO4 (100/0, 50/50, and 0/100 wt. %) deposits were conducted at 900 oC in air for 105 hrs at 15 hrs cycle. The hot corrosion kinetic of uncoated Inconel 600 alloy follows parabolic rate law when oxidized with 100% Na2SO4 deposits, whereas it follows a linear rate law when oxidized with 100% NaCl deposits and with (50% NaCl + 50% Na2SO4) deposits. In cyclic hot corrosion tests, the parabolic rate constant (kP) values for Cr- modified aluminide coating when oxidized with NaCl / Na2SO4 concentrations (100/0, 50/50, and 0/100 wt. %) deposits are: 2.67x10-6, 2.73x10-6, and 8.34x10-7 (mg2/cm4)/s. respectively. But for Y- doped chromium modified aluminide coating are: 2.10x10-6, 1.51x10-6, and 6.66x10-7 (mg2/cm4)/s. respectively, under the same test conditions. The kP values for both coated systems oxidized with 100% Na2SO4 deposits are one order of magnitude lower than that for 100% NaCl, and for (50% NaCl + 50% Na2SO4) deposits under the same test conditions.

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Romanowska, Jolanta, Maryana Zagula-Yavorska, Marek Góral, and Jan Sieniawski. "Zirconium Modified Aluminide Coatings Obtained by the CVD Method." Solid State Phenomena 227 (January 2015): 174–77. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.174.

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The paper presents the comparison of the structures of the zirconium modified aluminide coatings deposited on pure nickel by the CVD and method for different conditions, that is the gas flow and the time of deposition. The time of the aluminizing processes varied from 1.5 to 10 hours and the gas (HCl) flow varied from 0.4 to 1.4 l/min. Aluminum was deposited from the AlCl3 and zirconium from the ZrCl3 gas phases at 1040 oC. The obtained coatings were examined using an optical microscope (microstructure and coating thickness) a scanning electron microscope (chemical composition on the cross-section of the modified aluminide coating) and an XRD phase analyzer. Microstructures and phase compositions of coatings obtained at different process parameters do not differ significantly. In all cases, it is a triple zone structure. Chemical compositions of zones correspond to β-NiAl, γ’-Ni3Al and γ-Ni (Al) phases. The elongation of the time of zirconium-aluminizing process from 1.5 to 10 hours leads to the increase of the coating thickness from 30 to about 60 μm. The EDS analysis and concentration profiles of the cross-section of the coating showed the nickel outward diffusion from the substrate and the aluminum inward diffusion from the surface to the nickel substrate. In coatings deposited at a slow gas flow porosity was observed on the border between β-NiAl and γ’-Ni3Al layers. In coatings deposited at fast gas flow, zirconium does not form any inclusions but dissolves in the matrix. The Kirkendall porosity was not observed.

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Bogdanov, Artem I., Vitaliy P. Kulevich, and Victor Georgievich Shmorgun. "FEM Simulation of Sclerometric Test of Nickel Aluminide Layered Coatings." Materials Science Forum 1052 (February 3, 2022): 154–59. http://dx.doi.org/10.4028/p-i671cv.

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3D simulation by the finite element method (FEM) using MSC.Marc of sclerometric test with a conical indenter of a nickel aluminide intermetallic coating has been determined. The effect of the coating thickness and composition on the strain distribution has been determined. It is shown that an increase in the thickness of the coating makes it possible to reduce the magnitude of the maximum plastic strain. NiAl and Ni3Al coatings reduce maximum value of plastic strain and the penetration depth of indenter by 40% compared to a coating made of Ni2Al3.

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Journal articles on the topic 'Aluminide Coating'

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