Aluminide coating on nickel by fluidized bed CVD process (2023)

Table of Contents
Surface and Coating Technology Abstract introduce partial fragment experimental thermochemical considerations Experimental results Modeling of NiAl coating growth in conclusion thank you Thermodynamic evaluation of the Al-Ni system J. Alloy Compounds. Aluminum Diffusion Coating on Inconel 738 Using Preheated AlCl3+H2 Gas Mixture alma mater. science. project. Kinetic study of Cr and Al deposition on different metal substrates using CVD-FBR surf. coat. technology. Formation of TiC coating on steel by fluidized bed CVD process surf. coat. technology. Control of surface layer formation by aluminum cladding surf. coat. technology. Microstructural evolution of aluminide coatings on nickel-based cast superalloy CM-247 during one-step highly active aluminizing Metal. alma mater. trans. A Structure-Property Correlation of Aluminum Diffusion Coated Steel J. Alma mater. science. Kinetics of Phase Layer Growth During Nickel-Aluminum Plating Metal. trans. A Low Pressure Machining and Microstructure Evaluation of Unidirectional Carbon Fiber Reinforced Al-Ni Matrix Composites Mechanism of Al and Cr Particles Forming Slurry Aluminide Coatings Powder metallurgy and molybdenum aluminizing and carburizing of wrought Ti and Ti-6Al-4V alloys Microstructure and oxidation resistance of aluminide coatings deposited on pure nickel and hafnium-doped nickel superalloys by CVD method Aluminum Diffusion in Aluminide Coatings Deposited on Pure Nickel by the CVD Method Preparation and Hot Corrosion Behavior of Two Co-modified NiAl Coatings on Nickel-based Superalloys Effect of Combustion Synthesis in Slurry Aluminizing Formation Microstructure and oxidation behavior of plasma sprayed NiCoCrAlY coatings with and without Ta on Ti44Al6Nb1Cr alloy High-temperature cyclic oxidation behavior of platinum-rich γ-γ' coatings. Part I: Oxidation kinetics of the coated AM1 system after long-term exposure at 1100°C Effect of Aluminizing Properties on Microstructure and Isothermal Oxidation Behavior of Single-Phase β-(Ni,Pt)Al Coatings Microstructure and Oxidation Resistance of Inconel 100 Nickel Alloy Prepared by CVD Anti-coking Behavior of Fumed Aluminide Coatings Applied to High Performance Microalloyed (HP-MA) Steels FAQs Videos References

Surface and Coating Technology

Volume 141, Issues 2-3,

June 18, 2001

, pp. 275-282

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Current work involves the formation and modeling of aluminide diffusion coatings on nickel, andnickel alloyBy fluidized bed chemical vapor deposition (FBCVD) process. In this process, the object to be treated is suspended in the FB reactor filled with treatment agent. The latter is a mixture of coating-forming element donor powders (FeXAlyes), and filler material (Al2Europe3). As an activator of the process,halideUse compound (NH4chlorine). bed fluidizationinert gas(Ar). Precursor vapors of the elements to be deposited are formed in situ by the reaction of the donor with the activator. The produced coatings were examined by optical microscopy, SEM andEPMA.The modeling of the growth of nickel-aluminide coatings on nickel is based on the diffusion equation of aluminum in pure nickel, consideringintermetallic compoundPredicted from Ni-AlPhase Diagrams. For the considered aluminizing conditions, the model predicts the Al composition distribution as a function of time and Al concentration in the donor. The model is in good agreement with the experimental results.


Ni-Al intermetallics are commonly used to protect turbine blades used in the hot zone of engines. These blades are made of nickel superalloys, which are mainly attacked by high temperature oxidation and hot corrosion phenomena. The application of aluminum as an alloying element in diffusion coating is an effective way to improve the oxidation/corrosion resistance of treated components. This is obtained by forming a protective surface Al2Europe3Movie. A widely used technique for producing these coatings is the cladding process. This process takes place in a bed, which is the source of the elements needed to form the protective coating [1]. However, this method has certain disadvantages, as the powders used tend to sinter at the high temperatures of the process, so the treated parts are loaded and unloaded with the furnace at room temperature, reducing the productivity of the process, and the resulting coatings are often not average.

The reported studies are mainly concerned with the aluminum plating of nickel alloys by the infiltration process. Das et al. [2] studied the microstructural evolution of aluminide coatings on nickel-based superalloys. They concluded that for high-activity packaging processes, coating growth initially occurs primarily by inward diffusion, followed by an intermediate stage in which growth involves inward Al and outward Ni diffusion. In the final stage, Ni outdiffusion dominates the coating formation. Bahadur et al. [3] studied the morphology and structure of aluminide coatings on nickel by the infiltration method. Two types of procedures have been considered. The first, high-activity process, the coating is formed by the inward diffusion of aluminum, and the main phase is nickel2Al3and nickel aluminum. In this case, further annealing of the specimen was required in order to form the desired NiAl phase throughout the coating. The second type of processes are low activity processes. In this case, the coating mainly contains the NiAl phase and is formed by simultaneous outward nickel and inward aluminum diffusion.

A mathematical model is also proposed to simulate the accumulation cementation process. Hickel et al. [4] studied the simulation of nickel aluminization, a highly active process. The aluminum distribution during the aluminum formation and homogenization phases has been determined numerically. Based on the reported experimental results, the interdiffusion coefficient in the NiAl phase was estimated by an iterative method. The thermodynamics and kinetics of pack cementation were studied by Levine and Caves [5] and Sivakumar and Seigle [6]. Both studies examine the conditions under which the rate-determining step of deposition is gaseous or solid diffusion and conclude that, in low-activity processes, solid solution is rate-determining and the sample surface is in equilibrium with the accumulation. In highly active processes, both types of diffusion are rate-determining, possibly due to the high interdiffusion coefficient in the NiAl/Ni phase3Al5.

Although the packaging wrapping process is the most widely used aluminide coating deposition technique, it is difficult for this process to apply such coatings to particles with narrow channels (less than 0.5mm in diameter) because the packaging powder is difficult to feed into evenly These narrow channels then remove the powder.

Fluidized bed CVD combines the characteristics of a fluidized bed reactor, namely uniform temperature and gas distribution, with the principles of chemical vapor deposition [7]. Through this process, wear-resistant coatings (TiC, VC, CrXCyesand TiN) have been successfully deposited onto various steel grades [8], as well as diffusion coatings (Al, Si) onto nickel, nickel alloys, and ARMCO iron. Perez et al. [9], in the low-temperature FBCVD process, aluminum powder was used instead of FeAl as the donor, and the experimental temperature was lowered below the melting point of aluminum. Araki and Motojima [10] obtained an aluminide diffusion coating on Inconel 738 from preheated AlCl3 using FB at 1000°C3+H2gas mixture. In the reported experiments, AlCl3The gas was prepared by chlorinating aluminum metal with HCl gas at 330°C, and the surface of the aluminum coating was composed of NiAl phase.

partial fragment


The fluidized bed furnace used in the experiments consisted of a quartz tube still with a diameter of 63 mm. As shown in Figure 1, a stainless steel diffuser plate was installed at the bottom of the tube. The furnace with a power of 2 kW is heated by electrical elements. For the coating process, the retort is filled with donor powder (FeAl 36 at.% or 52-at.%. Al, grain size 63–160 μm) and filler oxide (Al2Europe3, grain size ≈175 μm), mainly for uniform heating

thermochemical considerations

The Al-Ni system has been the subject of research by Du and Clavaguera [11], who compared calculated and measured phase diagrams and thermodynamic quantities, showing that most of the experimental information can be satisfactorily explained by thermodynamic calculations. The thermodynamics of the process are simulated in the model described in this paper, assuming that the chemical reactions of the system reach equilibrium rapidly and the gaseous state mixes

Experimental results

The surface of the treated sample is smooth and gray. According to the optical observation of the sample by metallographic microscope, the coating is dense and uniform throughout its cross-section. Figures 3 and 4 show typical aluminide coatings deposited on NiCr23Fe alloy and Ni, respectively. In the case of a Ni substrate, the coating consists of two phases: an outer dark gray phase and an inner yellow phase

Modeling of NiAl coating growth

The coating growth model is based on the Al diffusion equation in pure Ni, taking into account the intermetallic compounds predicted by the Ni-Al phase diagram. The model was developed based on the work of Hickl and Heckel [4]. According to the phase diagram at 1000°C, the coating consists of Al phase3exist2(c) NiAl(d) Ni3Al(ε) and solid solution of aluminum in nickel (ζ). Figure 8 shows the expected morphology of the coating based on the phase diagram. in the text

in conclusion

According to the experimental results, it is feasible to form high-quality aluminide coatings on Ni and NiCr23Fe alloys by FBCVD process. Processing time is significantly reduced compared to packed bed processes, while the coating surface is dense and uniform. With the proposed process, no further annealing of the samples is required to obtain the NiAl coating. Experimental results show that the coating thickness increases similarly to the square root of

thank you

Prof. D.C. Papamantellos and Prof. Dr.rer.nat.Dr.-Ing.e.h. of METLAB. We thank W. Dahl of IEHK RWTH Aachen for his contributions to this field. The study was carried out within the framework of the joint Greek-German research and technology project "Integrated systems for fluidized bed heat treatment processes for advanced coatings", contract number: 2302.

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    Thermodynamic evaluation of the Al-Ni system

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    Aluminum Diffusion Coating on Inconel 738 Using Preheated AlCl3+H2 Gas Mixture

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  • Acronyms.Perezwait.

    Kinetic study of Cr and Al deposition on different metal substrates using CVD-FBR

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    Formation of TiC coating on steel by fluidized bed CVD process

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    Control of surface layer formation by aluminum cladding

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    Microstructural evolution of aluminide coatings on nickel-based cast superalloy CM-247 during one-step highly active aluminizing

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    Structure-Property Correlation of Aluminum Diffusion Coated Steel

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Additional references are provided in the full-text version of this article.

  • Low Pressure Machining and Microstructure Evaluation of Unidirectional Carbon Fiber Reinforced Al-Ni Matrix Composites

    2019, Journal of Materials Processing Technology

    Citation excerpt:

    On the other hand, Rizov and Magdeski (2010) studied the dependence of the thickness of the Ni2Al3 layer on the nickel content of aluminum melts and found that the thickness of the Al layer grew parabolically with time due to the diffusion process. However, other authors such as Wierzba et al. (2012), who studied the diffusion of the chemical vapor phase of aluminum deposited on nickel, Voudouris et al. (2001) examined fluidized bed chemical vapor deposition coatings and did not observe the formation of Ni2Al3 layers under similar conditions. The crystalline phases present were identified using XRD and the results were consistent with those expected in the literature (Figure 5).

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    Continuous carbon fiber-reinforced Al-Ni matrix composites were fabricated by immersing an interlayer laminate design of aluminum foil, nickel mesh belt, and nickel-coated carbon fibers in an aluminum melt at 900°C for 15 seconds. Samples with and without fibers were compared. Scanning electron microscopy (SEM) showed a strong bond at the matrix/reinforcement interface, showing no signs of defects or debonding. Light microscopy (LM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and Vickers microhardness testing indicated the presence of Ni2Al3The hardness of the intermetallic phase and the NiAl intermetallic phase in the composites are 970 ± 27 and 450 ± 23 HV, respectively, which is consistent with the reaction diffusion values ​​reported in the literature. Microstructural analysis and image binarization of the interfacial region indicated achievable fiber contents between 15% and 40% vol, and the interface could be improved by further homogenizing the fiber distribution.

  • Mechanism of Al and Cr Particles Forming Slurry Aluminide Coatings

    2019, Surface and Coating Technology

    Citation excerpt:

    High-temperature low-reactivity coatings grow by predominant outdiffusion of nickel at high temperatures (typically between 1000 °C and 1100 °C) [4,10–13]. In this case, the thermodynamic activity of Al is kept low by alloying it with Cr [8,15,16], Fe [17] or Ni [4] to directly form the β-NiAl phase. Low-reactivity coatings exhibit higher oxidation resistance than high-reactivity coatings due to larger grain size, fewer diffusion paths, and the formation of a clean β-NiAl phase free of precipitates and carbides [10,12, 13].

    The mechanism of alternating deposition of Al and Cr particles followed by heat treatment in Ar to form NiAl2 coatings was investigated on pure Ni. To this end, custom-made quantities of Al and Cr water-based slurries were deposited sequentially on pure nickel following two different structures (Al/Cr and Cr/Al bilayer systems). Regardless of the coating structure, the addition of Cr particles was found to reduce the thermodynamic activity of Al during aluminizing by forming AlXchromiumyesstage. This greatly limits the indiffusion of Al into the substrate at low temperatures (e.g. 650°C). And the formation of δ-Ni2Al3Still observed in the Al/Cr bilayer system, its formation is completely suppressed by the Cr/Al system. By adjusting the composition of the deposited layer, that is, the thickness of the Cr and Al layers, the β-NiAl phase can be directly formed by further annealing at high temperature (e.g., 1000°C for 3h). This facilitates the outdiffusion of nickel and the dissolution of the synthesized aluminumXchromiumyesstage. An undissolved chromium-rich phase was also observed in the diffusion layer, confirming the outgrowth typical of low-reactivity aluminized coatings.

  • Powder metallurgy and molybdenum aluminizing and carburizing of wrought Ti and Ti-6Al-4V alloys

    2016, Materials Characterization

    The wear resistance and high temperature oxidation resistance of some titanium-based alloys need to be enhanced, which can be effectively achieved by surface treatment. Molybdenum is a surface treatment that introduces molybdenum into the surface of titanium alloys to form a molybdenum-containing wear-resistant surface layer, while it has been reported that aluminizing titanium-based alloys can improve their high-temperature oxidation properties. Although infiltration and other surface modification methods have been used to molybdenize or aluminize wrought and/or cast pure titanium and titanium alloys, such surface treatments have not been reported on titanium alloys produced by powder metallurgy (PM) . A critical understanding of the process parameters for simultaneous one-step molybdenum aluminizing of titanium alloys by stack carburizing and the main mechanisms of the process has not been reported. The current research work describes the surface modification of titanium and Ti-6Al-4V prepared by molybdenum aluminide PM and analyzes the thermodynamic aspects of the deposition process. Similar coatings were also deposited on wrought Ti-6Al-4V and compared. The coatings were characterized using scanning electron microscopy and X-ray diffraction. For titanium and Ti-6Al-4V, the use of powder packages containing ammonium chloride as an activator results in the deposition of molybdenum and aluminum to the surface, but also introduces nitrogen, resulting in the formation of a thin titanium nitride layer. In addition, various titanium aluminides and mixed titanium aluminum nitrides are formed. The appropriate conditions for molybdenum aluminization and the phases expected to form were successfully determined by thermodynamic equilibrium calculations.

  • Microstructure and oxidation resistance of aluminide coatings deposited on pure nickel and hafnium-doped nickel superalloys by CVD method

    2015, Civil and Mechanical Engineering Archives

    Aluminide coatings were deposited by CVD on pure nickel and hafnium-doped nickel superalloys Mar M247, Mar M200 and CMSX 4. All coatings consist of two layers: an outer layer, containing the β-NiAl phase, and an interdiffused layer. The interdiffusion layer on pure nickel consists of γ'-Ni3Al and NiAl phases on superalloys. MC and M23C6Carbides other than the NiAl phase were found in the interdiffusion region of Mar M247 and Mar M200, while topologically close-packed phases such as TCP σ phase and R phase were found in the interdiffusion region of CMSX 4. More hafnium (Mar M247 and Mar M200) are more resistant to degradation during cyclic oxidation. The amount of 1.5–1.8wt.% hafnium in the substrate makes HfO2Formation of "nails" in the scale during oxidation of the aluminized Mar M247 and Mar M200 superalloys. Improved lifetime of coated CMSX 4 superalloys obtained by platinum modification. Platinum reduces the diffusion of alloying elements such as Ti and Ta from the substrate to the coating and scale, stabilizes the NiAl phase and delays NiAl→Ni3Al phase transition.

  • Aluminum Diffusion in Aluminide Coatings Deposited on Pure Nickel by the CVD Method

    2014, Calphad: Computer Coupling of Phase Diagrams and Thermochemistry

    (Video) mod-01 Lec-09 CVD of Coatings

    Aluminum diffusion in aluminide coatings deposited on nickel by the CVD method was studied. The microstructure, chemical composition and phase composition of the coatings were examined by SEM, EDS and XRD techniques. A three-domain structure was revealed. β-NiAl phase is located on the coating surface, while γ-(Ni) and γ'-Ni3Al formed the deeper part of the coating. Diffusion coefficients were calculated from the concentration profiles in coatings deposited at 1000°C and 1050°C for different times (15 min, 1 h, 4 h, and 8 h). The program is based on the classic finite difference method (FDM). At the same time, the three-phase diffusion coefficient is calculated, and the influence of the diffusion coefficient of one phase on the diffusion coefficient of the adjacent phase is considered. The calculated results are consistent with literature data obtained separately for each analysis stage.

  • Preparation and Hot Corrosion Behavior of Two Co-modified NiAl Coatings on Nickel-based Superalloys

    2013, Corrosion Science

    Citation excerpt:

    It can be divided into four steps: (i) generation of active Co or Al atoms; (ii) active atoms migrate to the substrate surface by gas diffusion; (iii) are absorbed and deposited on the surface; (iv) by solid diffusion Diffuses inwardly into the substrate. Usually the two diffusion steps (ii) and (iv) are rate-determining steps, but in a low-pressure environment, the active atoms are rapidly transported to the substrate surface, so step (iv) is only the rate-determining step [18, 19]. Figure 11 schematically illustrates the formation mechanism of Co and Al deposited separately.

    Two kinds of cobalt-modified aluminide coatings with different cobalt content were prepared by the combination of infiltration and chemical vapor deposition. Type I hot corrosion tests of two Co-modified coatings versus a simple aluminide coating at 900 °C. The results show that the addition of cobalt can improve the corrosion resistance of the coating in sulfate, but the degradation of the coating will be aggravated when the chloride salt is added. The formation mechanism of the Co-modified aluminide coating and the corrosion mechanism during the corrosion test are also discussed.

View all citing articles on Scopus
  • research article

    Effect of Combustion Synthesis in Slurry Aluminizing Formation

    Intermetallic Compounds, Volume 44, 2014, Pages 8-17

    The slurry process has been investigated for many years as an alternative to traditional CVD-derived aluminizing to achieve similar diffusion coatings. This study investigates the mechanism of coating formation during the heat treatment of pure nickel using a slurry containing a large number of microscopic aluminum particles. In the temperature range of 550°C–1000°C, aluminum diffuses into the nickel matrix, promoting the formation of an intermetallic nickel aluminide layer. To control this process, it is important to understand the mechanisms that occur at the initial stage, when metallic aluminum powder melts and comes into contact with nickel. While the conversion of tightly compacted nickel-aluminum to aluminides by combustion synthesis is well known, DTA measurements were performed to investigate if and when this process occurs in loosely packed powders. Two compositions of nickel with aluminum or eutectic Al-Si alloy particles were used to reveal the potential influence of the melting point of the aluminum alloy particles. The effect of the atmosphere was investigated by comparing the results of exposure to argon and air. Subsequently, both powders were applied to pure nickel substrates and the formation of the coating during heat treatments at 600°C, 650°C and 700°C was investigated for comparison with the more complex mechanism of slurry aluminization. The results clearly demonstrate the importance of combustion synthesis for the formation of slurry coatings on nickel. Based on the observations, four steps leading to the formation of aluminides and the subsequent growth of the aluminide layer were identified: after the aluminum powder was melted, a molten aluminum network formed within and between the particles, followed by the dissolution of nickel in the aluminum melt. Combustion synthesis between nickel and aluminum occurs if sufficient aluminum is available. After this highly exothermic reaction, solid-state diffusion controls the further formation of a slurry coating on the nickel. Finally, the mechanism is verified by coating industrial superalloys with aluminum-based slurries in air and argon.

  • research article

    Microstructure and oxidation behavior of plasma sprayed NiCoCrAlY coatings with and without Ta on Ti44Al6Nb1Cr alloy

    Corrosion Science, Volume 136, 2018, Pages 244-254

    Ta-containing and Ta-free NiCoCrAlY coatings were plasma sprayed onto Ti44Al6Nb1Cr alloys to study their microstructure and oxidation resistance at 900°C for 100 h. The results show that the oxidation resistance of NiCoCrAlY coating is better than that of NiCoCrAlYTa coating. aluminum formation2Europe3Scaling on the NiCoCrAlYTa coating was suppressed due to the low Al concentration and the dragging effect of Ta. In addition, the loose NiO/CoO scale on the NiCoCrAlYTa coating facilitates the inward diffusion of oxygen. As a result, an aluminum2Europe3Forms a layer at the interface that inhibits interdiffusion between the coating and the substrate.

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  • research article

    High-temperature cyclic oxidation behavior of platinum-rich γ-γ' coatings. Part I: Oxidation kinetics of the coated AM1 system after long-term exposure at 1100°C

    Corrosion Science, Volume 144, 2018, Pages 127-135

    The cyclic oxidation behavior of several Pt-rich γ-γ' bonded coatings on AM1 superalloys was investigated at 1100 °C, and compared with β-(Ni,Pt)Al coated and uncoated superalloys. compared. The AM1 superalloy exhibits outstanding properties due to optimized Hf doping and low sulfur content. Compared to the reference system with β-(Ni,Pt)Al coating, the Pt-enriched γ-γ′ bond coating shows better resistance to cyclic oxidation. The addition of aluminum during fabrication was found to be beneficial in improving the oxidation behavior of Pt-rich γ-γ' bond coats. Their separation is due to insufficient aluminum content below the TGO, whereas the reference system is wrinkled.

  • research article

    Effect of Aluminizing Properties on Microstructure and Isothermal Oxidation Behavior of Single-Phase β-(Ni,Pt)Al Coatings

    Corrosion Science, Volume 106, 2016, Pages 43-54

    In this study, single-phase β-(Ni,Pt)Al coatings were fabricated in the sequence of Pt electroplating followed by “up-clad” aluminum plating. Three main process factors, initial Pt thickness, aluminizing temperature, and aluminizing time, were selected to study their effects on the microstructure of the final β-(Ni,Pt)Al coating. The isothermal oxidation behavior of coatings with different Pt thicknesses was evaluated in static air at 1100 °C. An empirical equation is proposed to show the relationship between the coating thickness and the three process parameters. The β-(Ni,Pt)Al coating with 5 μm Pt exhibited the best oxidation resistance due to the excellent adhesion of scale.

  • research article

    Microstructure and Oxidation Resistance of Inconel 100 Nickel Alloy Prepared by CVD

    Surface and Coating Technology, Volume 304, 2016, Pages 584-591

    This study concerns thermal protection by covering an IN 100 nickel superalloy with a diffused β-NiAl intermetallic layer produced by a CVD method. Oxidation resistance tests were performed in air at 950°C. Alloy samples with and without the intermetallic compound layer were subjected to 24 heating-cooling cycles, each lasting 24 hours, and their oxidation resistance was compared. During the oxidation test, the induced stress in the coating was analyzed by the finite element method, which is also used to monitor the growth of α-Al2Europe3Scale during successive thermal cycles (birth and death elemental analysis). The alumina scale appears to be continuous and dense. The stress level depends on the surface roughness of the interface between the intermetallic compound layer and the oxide scale, being highest in its surface peak area and lowest in the stressed valley area.

    The coating consists of a ~11 μm thick layer of diffuse β-NiAl intermetallic compound and α-Al2Europe3The flakes are highly resistant to thermal shock and very good corrosion resistance.

  • research article

    Anti-coking Behavior of Fumed Aluminide Coatings Applied to High Performance Microalloyed (HP-MA) Steels

    Surface and Coating Technology, Volume 389, 2020, Item 125607

    In this study, aluminide coatings were applied to high performance microalloyed (HP-MA) steels by a vapor phase aluminizing process to investigate the coking resistance of the coated steels. In this regard, a powder mixture with a 10% Al-5% NH composition4Cl-85% Aluminum2Europe3和 30% Al-15% NH4Cl- 55% Aluminum2Europe3Used in coating process, hereinafter named as Al-10 and Al-30 coating respectively. The scorch resistance of the samples was evaluated using a simulated cracking device. In this setup, samples are placed in a tube furnace and exposed to ethane (C2H6) and argon as the main feedstock, using optimized parameters. The coking test results showed that the bare steel was mostly covered by catalytic coke; while the properties of the gas-phase aluminide-coated steel were improved. The formation of catalytic coke on bare steel is due to the reaction between the feedstock and active matrix elements such as Fe and Ni. In fact, the carbon released during the cracking process diffuses into the bare steel and removes the metal crystals on the surface through their outgrowth, eventually leading to the formation of catalytic coke. Furthermore, it was observed that Al-30 coatings performed better than Al-10 coatings. In fact, for the Al-10 coating, the amount of catalytic coke is reduced compared to bare steel, while the Al-30 coating is mainly covered with spherical carbon deposits, which are released by chemical reactions in the gas phase. of. In this regard, the scorch resistance of the Al-10 and Al-30 coatings is 63% and 80%, respectively. This is mainly due to the higher content of Al and Cr in the Al-30 coating.

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What is aluminide coating? ›

Also known as aluminizing, aluminide coating is a high temperature chemical process where aluminum diffuses into the surface of the base metal to form an aluminized layer or coating. This process is commonly applied to carbon steels, low, and medium alloy steels and stainless steels and superalloys like Inconel.

How does CVD coating work? ›

Chemical vapor deposition is a process that involves the reaction of a volatile precursor which is injected into a chamber (typically under vacuum). The chamber is heated to a reaction temperature that causes the precursor gas to react or break down into the desired coating and bond to the material surface.

How thick is aluminide coating? ›

The outer zone of the aluminide coating (in Figure 2 the “A” zone) had a thickness of about 10–24 μm. In the interior zone of the aluminide coating (in Figure 2 the “B” zone) with thickness of 12–16 μm column structures were observed.

What is application of CVD coating? ›

CVD coatings are used in many manufacturing applications as a wear-resistant coating: carbide milling and turning inserts, wear components, some plastic processing tools, etc. However, the most common application for CVD coating is for metal-forming tools.

What is AlTiN coating used for? ›

Calico-AlTiN is normally applied to steels, hardened steels, and stainless steel materials where high wear resistance and lubricity are needed. AlTiN coating provides exceptional oxidation resistance and extreme hardness.

What is AlTiN coating for? ›

AlTiN is a good coating for dry machining and machining titanium alloys, Inconel, stainless alloys, and cast iron.

What is CVD coating advantages and disadvantages? ›

Some of the advantages of CVD are production of uniform film with low porosity, high purity, and stability. However, it has some disadvantages also, as it requires highly expensive instrumentation and emits toxic gaseous by-products during reaction.

What is the difference between CVD and PVD coating? ›

Conclusion – PVD vs CVD Coating

To summarise, PVD and CVD both function as methods of binding the desired layer to a substrate material. The primary difference is that PVD uses a liquid source material to create a thin film, while CVD uses a gaseous source material.

How thick is CVD coating? ›

The average thickness of our various CVD coatings is 5-10 microns (. 0002-. 0004”).

What is the hardest aluminum coating? ›

Sulfuric acid Hardcoat Anodizing is a hard, wear resistant coating for aluminum.

What are the different types of aluminum coatings? ›


The aluminum coatings available can be categorized into four types: Anodized, Fluoropolymer, Baked Enamel, and Wood Grain Powder Coating.

How thick is aluminised steel coating? ›

Typical sizes available are 1000mm or 48" (1220 mm) wide - thickness range 0.5mm - 1.2mm are standard heavy gauges up to 3mm on request.

What are the types of CVD coating? ›

Some CVD techniques are atmospheric-pressure CVD, low-pressure CVD, ultrahigh vacuum CVD, plasma-enhanced CVD, microwave plasma-assisted hot filament CVD, metal–organic CVD, photo-initiated CVD, atomic layer deposition, spray pyrolysis, liquid-phase, epitoxy, etc.

What is the hardness of CVD coating? ›

Ionbond CVD 02 TiC
Technical Data
Thickness range6 - 10 µm
Microhardness, HV 0.053200
Friction vs. Steel (dry)0.20
4 more rows

What materials are in CVD coating? ›

The materials used in CVD coating systems range from silicon compounds to carbon, to organofluorine or fluorocarbons, and nitrates like titanium nitride.

What is the toughest coating for steel? ›

Epoxy Steel Coatings:

Epoxies are known for having excellent adhesion to steel and provide good chemical resistance. They are also often sold as “surface tolerant”, which means they will adhere well to surfaces with minimal surface preparation.

What is the color of AlTiN coating? ›

Aluminum Titanium Nitride, black in color, is a harder, smoother variation of TiAlN. Created for abrasive and high temperature applications (> 800ºC). AlTiN creates an aluminum oxide layer during the cutting process. It is increasing in popularity for drilling, counterboring and milling.

Can you cut aluminum with AlTiN coating? ›

AlTiN Nano

Superior results, extended tool life, and reduced cycle times over traditional AlTiN coatings in demanding applications where setup minimizes runout and vibration. Not recommended for use in aluminum and aluminum alloys.

What is the difference between DLC coating and AlTiN coating? ›

AlTiN is used for a variety of cutting tools and moulds. AlTiN coatings have a hardness of approximately 3300 ± 300 HV and are used for universal abrasion protection. DLC C coatings have a hardness of 900 ± 50 HV, but have a very low coefficient of friction (COF) against steel (0.08).

Is AlTiN coating good for stainless steel? ›

Due to its penchant for demanding applications, AlTiN is recommended for hardened steels, hardened stainless, tool steels, titanium alloys, and aerospace materials. These applications often create high levels of heat that AlTiN Nano was designed to combat.

Which coating is best for tool steel? ›

CVD applications

CVD coatings are the first choice when it comes to wear resistance, such as for general turning operations of stainless steels and when drilling into steel, where the thick CVD coatings provide resistance to crater wear.

Which is better CVD or PVD? ›

PVD is a line-of-sight process allowing for a thinner coating and therefore a sharper edge. CVD produces a thicker coating more effective as a thermal barrier. The machining footage in this video shows the difference as we experiment with different coatings in both roughing and finishing passes in 4140 steel.

Is CVD better than PVD? ›

Although CVD coating can greatly improve cutting tool performance, but it comes with a disadvantage that CVD-coated equipments are more fragile than PVD-coated ones due to residual tensile stress during the process.

Why is CVD preferred? ›

One of the biggest advantages of using CVD is that it can be used to evenly coat irregular surfaces, including screw threads and recesses. The process is also extremely versatile; it has been used with an extremely wide range of elements and compounds. CVD also produces a thin film with very high purity and density.

What is the difference between CVD and ALD? ›

CVD is a continuous process in which all reactants are given simultaneously to build the film, whereas ALD is done in two half-reactions, one after the other.

What are the disadvantages of CVD? ›

Disadvantages of CVD
  • Chemical and safety hazards caused by the use of toxic, corrosive, flammable and/or explosive precursor gases.
  • The use of more sophisticated reactor and/or vacuum system by CVD variants are not scalable because of high cost, size limitations and narrow applications.
Jul 16, 2021

Which is better electroplating or PVD coating? ›

The film adhesion achieved in PVD process is far better than what is provided in electroplating process due to higher energy levels of the ions arriving at the surface of the product.

What is the hardest PVD coating? ›

Chromium nitride (CrN) has a lot to offer. It's exceptionally hard and tough. It reduces friction, is resistant to sliding and impact wear, has excellent corrosion and oxidation resistance, and is a non-stick option for many other materials.

How many microns is PVD coating? ›

In general, PVD coatings are thin film and are in the range of 1 to 5 microns.

What is the best aluminium coating? ›

Polyvinylidene Fluoride (PVDF) Resin

Since PVDF coatings also resist fading, corrosion, and chalking, they're good choices for aluminum components in highly noticeable areas, such as on building exteriors.

What is the highest quality aluminum? ›

Grade 7000

Known as the zinc grades – zinc being the largest alloying element, the 7000 series grades are the hardest and strongest commercial grades of aluminium. Grade 7075 is the most common of the 7000 series grades. It is an extremely high strength alloy; the strongest of all commercial grades of aluminium.

What coating stops aluminium from corroding? ›

You can choose from several protective coating options: powder coating and anodizing. Anodizing involves forming a natural oxide layer on the metal's surface. While it may help in making the metal less susceptible to corrosion, the resulting layers are oftentimes thin.

What are the advantages of aluminizing? ›

In addition to oxidation resistance, aluminizing also has sulfidation resistance and carburization resistance. It provides chemical protection against hydrogen sulfide (H2S) and sulfur oxides (SO2, SO3). Aluminized steel is more corrosion resistant than carbon steel and even aluminum on it's own.

What is aluminization? ›

Aluminizing, also known as alonizing is a high-temperature chemical process whereby aluminum vapors diffuse into the surface of the base metal forming new metallurgical aluminide alloys.

What are four types of coatings? ›

Here, we'll describe the benefits and tradeoffs of four of the most common generic coating types: Epoxies, polyurethanes, polysiloxanes and zinc-rich primers, providing examples of how each might be used in a total coating system.

Is aluminised steel better than stainless steel? ›

Aluminized steel conducts heat much more effectively compared to stainless steel. Stainless steel will distort significantly when it is heated to high temperatures. This makes aluminized steel the best choice for making vehicle exhaust systems.

What are two 2 benefits of using aluminised and stainless steel in muffler construction? ›

With mild steel pipes, the aluminium will protect the steel only until it's scratched, after which moisture and dirt will inevitably get into the metal and result in worsening corrosion. Stainless pipes simply last longer; tube-painting or re coating isn't necessary.

Is aluminised steel good? ›

Aluminised steel – a great choice for the average user

Aluminised steel starts out as mild steel. It is then coated inside and out with an aluminium coating that protects it from rust. At Manta, we also give all our aluminised steel systems a coat of heatproof paint for extra protection.

What are the 6 types of CVD? ›

A “state of the science” review details the most reported symptoms of 6 cardiovascular diseases (CVDs): heart attack, heart failure, valve disease, stroke, heart rhythm disorders, and peripheral artery and vein disease (PAD and PVD).

How do you increase coating hardness? ›

The increase in hardness is not favorable because it may affect other properties but if you want to increase the hardness of your paint you can accelerate the drying of your paint by using short alkyd resin with NC and also use dibutyl phthalate as placiticzer to maintain your balance of hardness.

How do you measure hardness of coating? ›

One of the most common methods of determining coating hardness is the pencil hardness test, also known as the Wolff-Wilborn method, where a pencil of a known hardness is pushed across the coating at a specified angle, under a constant force.

Why is hardness of coating important? ›

Why does coating hardness matter? Component durability is a key influencing factor in every manufacturing business. Elevating the damage tolerance level of components improves the item's durability and service longevity. The hardness value indirectly indicates the damage tolerance of material.

What are the disadvantages of titanium Aluminide? ›

The disadvantages of TiAl alloys are a high impurity level, primarily with interstitial impurities (oxygen, nitrogen, etc.), and difficult formation of a nonporous material, which have a negative impact on mechanical properties.

Is titanium Aluminide a ceramic? ›

Neither metal nor ceramic: Titanium aluminides, the “best of both worlds,” are produced at GfE. GfE starts commercial production of Titanium Aluminides in 1995. To produce the material efficiently, an entirely new process chain is developed from already existing technologies.

What are the three types of coating? ›

Coatings are varied, but primarily fall into three categories: Architectural, Industrial, and Special Purpose.

What is titanium Aluminide made of? ›

The alloys contain titanium, 38 to 46 atom % aluminum, 5 to 10 atom % niobium, with small amounts of Cr, Si and Ni added according to required properties. Titanium aluminide alloys are characterized by a low density, a high rigidity and good corrosion resistance.

Why don't we use titanium instead of steel? ›

The problem? “It's too expensive,” Minor says of industrial-grade titanium or titanium alloys that might otherwise replace steel when only the strongest, most durable materials will suffice. In fact, the cost of making titanium is about six times greater than that of stainless steel.

Why is aluminum better than titanium? ›

Compared to grade 2 titanium, 7075-T6 aluminum is 33% lighter and has a higher tensile strength, strength-to-weight, and stiffness-to-weight. Aluminum can also be anodized - effectively growing an ultra hard, ultra durable skin on the outside of the metal.

What are the benefits of titanium vs aluminum? ›

While both materials have excellent corrosion resistance, manufacturers figured that titanium is more corrosion-resistant than aluminum. Titanium is more inert and has more biocompatibility with good application in many industries. Aluminum forms a layer of oxide to make more non-reactive materials.

What is titanium Aluminide used for? ›

Titanium aluminide (TiAl)-based alloys are developed for high-temperature applications in aerospace and automotive industries because of their attractive properties, such as low density, high specific strength, high specific stiffness, and good high-temperature properties.

What are the 4 types of titanium? ›

The four grades, or varieties of titanium alloys are Ti 6AL-4V, Ti 6AL ELI, Ti 3Al 2.5 and Ti 5Al-2.5Sn. Ti-6AL-4V is the most commonly used of the titanium alloys. It is therefore commonly referred to as the titanium alloy “workhorse.” It is believed to be used in half of the usage of titanium around the world.

What metals are in titanium alum? ›

not to be confused with Ti-6Al-4V-ELI (Grade 23), is the most commonly used alloy. It has a chemical composition of 6% aluminum, 4% vanadium, 0.25% (maximum) iron, 0.2% (maximum) oxygen, and the remainder titanium.

What is the most widely used coating? ›

Epoxy coating is one of the most widely used protective coatings on the market due to its versatility and durability. It comes in two parts – a resin that must be mixed with a hardener before application – which makes it easy to customize for different surfaces and needs.

Which coating is the best? ›

The ceramic coating is very durable and can last 5-7 years depending on the kind of coat applied. Scratch-resistant and helps prevent swirl marks: The hard nature of ceramic coating does a good job of protecting the car's surface against scratches and swirls keeping the surface smooth and shiny.

What are two 2 types of coatings used for deep fried products? ›

The best 5 types of coating for your recipes
  • Breading. A true classic. ...
  • Tempura. You can make tempura batter by mixing flour, baking powder, salt, and very cold water. ...
  • Romana. This is a classic coating process from Spain. ...
  • Andalusian style or coating with flour.

What is the toughest titanium alloy? ›

Grade 4 is known as the strongest of the four grades of commercially pure titanium. It is also known for its excellent corrosion resistance, good formability and weldability. Though it is normally used in the following industrial applications, Grade 4 has recently found a niche as a medical grade titanium.

What is titanium nickel alloy called? ›

Nickel titanium, also known as Nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages.

What is the cost of titanium Aluminide per kg? ›

Aluminum Titanium Boron Master Alloy at Rs 250/kilogram | Aluminum Master Alloy in Pune | ID: 19555862688.


1. Mod-01 Lec-02 CVD Reaction
2. mod-01 Lec-08 CVD of Metals
3. Lecture 32 : Diffusion Coating Processes
(IIT Kharagpur July 2018)
4. Atomic Layer Deposition of copper - If you like sputtering, you'll love this!
(Applied Science)
5. Coating on Abrasive Grain
(Ch-11 Mechanical Engineering & related branches)
6. Surface Gradient Coatings for IVD
(Paul Denman)


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