Microstructures of thin and thick slurry aluminide coatings on Inconel 690

Rasmussen, Anders Juul; Agüero, Alina; Gutiérrez, M.T.; Østergård, M.J.L.

doi:10.1016/j.surfcoat.2007.06.056

Cited by 37 publications

(15 citation statements)

References 15 publications

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“…Slurry aluminisation can provide advantages in the process, that is, simplicity and economical efficiency. Typical slurries manufactured on the base of aluminium powder (as an active component) and of the solution of an organic binder are widely used [9][10][11][12]. When the polyvinyl alcohol is used as the organic binder in the slurry, slurrycoated specimens have to be held at a temperature of 300°C for 4 h [12] or 400°C for 3 h [10] to expel the binder and only after that heat treated.…”

Section: Introductionmentioning

confidence: 99%

Microstructure of Al‐Si Slurry Coatings on Austenitic High‐Temperature Creep Resisting Cast Steel

Kochmańska

2018

Advances in Materials Science and Engineering

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is 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. e function of aluminide coatings is the protection of the equipment components against the high-temperature corrosion in a carburising atmosphere under thermal shock conditions. e obtained coatings had a multilayered structure composed of intermetallic compounds. e 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. e 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. e coatings were formed on both: the ground surface and on the raw cast surface. e 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. e rotatable design was used to evaluate the effect of the production parameters on the coatings thickness. e correlation between the technological parameters and the coating structure was determined.

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Section: Introductionmentioning

confidence: 99%

Microstructure of Al‐Si Slurry Coatings on Austenitic High‐Temperature Creep Resisting Cast Steel

Kochmańska

2018

Advances in Materials Science and Engineering

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“…Metallic alloys or steels with high percentages of Al and Cr are selected for steam oxidation at high temperature, because of the susceptibility of Al and Cr to form alumina (Al 2 O 3 ) and chromia (Cr 2 O 3 ) when exposed to oxygen. These layers are effective because of their thermodynamic stability and relatively high melting points; moreover the mass transportation through these layers is usually very slow [6,7].…”

Section: Introductionmentioning

confidence: 99%

Improvement in Resistance to Steam Oxidation of Aluminide-Coated AISI 304 and AISI 316 Steel Produced by Chemical Vapor Deposition in a Fluidized Bed Reactor

2015

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Various techniques have been used to deposit aluminium on ferritic and austenitic steels to increase their oxidation resistance. An aluminide coating was deposited on AISI 304 and AISI 316 stainless steels by chemical vapor deposition at 580°C for 1.5 h in a fluidized bed reactor. The as-deposited samples were treated at 750°C in Ar atmosphere for 2 h. Scanning electron microscopy/energy-dispersive X-ray spectroscopy and X-ray diffractometry were used to study morphology and composition. Deposition results indicated that FeAl, Fe 2 Al 5 , Al 0.99 Fe 0.99 Ni 0.02 , AlNi, and Fe 2 AlCr had formed. Specimens were oxidized in a steam loop at 750°C for 1000 h to evaluate the steam oxidation resistance of the coating. The thermodynamic software package Thermo-Calc was used for simulations under similar experimental oxidation conditions. Gravimetric measurements verified that the mass change of the coated samples decreased up to 100 times with respect to uncoated steels.

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“…A disadvantage of gas additives in steam reforming plants is the need for continuous feed and subsequent cleaning of the process gas. A different strategy is to alloy Ni with metals that may form protective oxide coatings, for instance Ti or Al [19,20,21,22,23,24].…”

Section: Introductionmentioning

confidence: 99%

“…This will result in the existence of various Ni-aluminide phases in the coating [24]. In this work, we focus on the case of oxide failure on the -Ni 3 Al and -NiAl surfaces and investigate, which adsorbates are present on the metallic surfaces under metal dusting conditions.…”

Section: Introductionmentioning

confidence: 99%

First-principles investigations of Ni3Al(111) and NiAl(110) surfaces at metal dusting conditions

et al. 2011

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We investigate the structure and surface composition of the -Ni 3 Al(111) and -NiAl(110) alloy surfaces at conditions relevant for metal dusting corrosion related to catalytic steam reforming of natural gas. In regular service as protective coatings, nickel-aluminum alloys are protected by an oxide scale, but in case of oxide scale spallation, the alloy surface may be directly exposed to the reactive gas environment and vulnerable to metal dusting. By means of density functional theory and thermochemical calculations for both the Ni 3 Al and NiAl surfaces, the conditions under which C O and O H adsorption is to be expected and under which it is inhibited, are mapped out. Because C O and O H are regarded as precursors for nucleating graphite or oxide on the surfaces, phase diagrams for the surfaces provide a simple description of their stability. Specifically, this study shows how the C O and O H coverages depend on the steam to carbon ratio (S/C) in the gas and thereby provide a ranking of the carbon limits on the different surface phases.

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Microstructures of thin and thick slurry aluminide coatings on Inconel 690

Cited by 37 publications

References 15 publications

Microstructure of Al‐Si Slurry Coatings on Austenitic High‐Temperature Creep Resisting Cast Steel

Microstructure of Al‐Si Slurry Coatings on Austenitic High‐Temperature Creep Resisting Cast Steel

Improvement in Resistance to Steam Oxidation of Aluminide-Coated AISI 304 and AISI 316 Steel Produced by Chemical Vapor Deposition in a Fluidized Bed Reactor

First-principles investigations of Ni3Al(111) and NiAl(110) surfaces at metal dusting conditions

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