Oxidation Behavior of Hf-Modified Aluminide Coatings on Inconel-718 at 1050°C

Wang, Yongqing; Smialek, James L.; Suneson, Marc

doi:10.6000/2369-3355.2014.01.01.4

Cited by 15 publications

(5 citation statements)

References 67 publications

(90 reference statements)

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“…However, experiment performed by [45] shows that only Dy doping can give reduction in the scale growth rate enhanced the oxide scale adhesion mainly due to the formation of oxide pegs at the scale/alloy interface while Hf doping had no significant effect on scale adhesion. In addition, this is closely related with authors in [48] in which they had stated that over doping with Hf may result in excess of HfO 2 formation into the coating. This is because, low hafnium solubility also contributes to Hf-rich particle precipitation during oxidation [49].…”

Section: Effect Of Re On Bond Coat Oxidation Performancesupporting

confidence: 76%

Review on Nickel Aluminide based Bond Coat Properties and Oxidation Performance for Thermal Barrier Coating (TBC) Application

Kadir

Manap²,

Satgunam³

et al. 2018

IJET

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Thermal Barrier Coating (TBC) as protective coatings are applied to maintain efficiency and prevent structural failures mainly in gas turbine system. This paper reviews on recent bond coating from Nickel aluminide bond coat with addition of Reactive Elements (RE). This paper also reviews the major concern in TBC with presence of different Reactive Element (RE) added in term of RE composition, properties and oxidation test performance. Recent studies are more focusing on few REs including Ce, Hf, La, Y and Zr based on oxidation property test results. The comparisons clearly show that ceramics addition are superior for bond coat mechanical and thermal properties improvement while RE addition such as Ce and Zr present excellent oxidation performance at 900°C and above.

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Section: Effect Of Re On Bond Coat Oxidation Performancesupporting

confidence: 76%

Review on Nickel Aluminide based Bond Coat Properties and Oxidation Performance for Thermal Barrier Coating (TBC) Application

Kadir

Manap²,

Satgunam³

et al. 2018

IJET

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“…Hf additions have been shown to enhance the scale adhesion in alumina forming alloys, for example see [44,47,78,83,84,85,86]. In the alloy OHC3 there was no oxide buckling.…”

Section: Discussionmentioning

confidence: 99%

On the Microstructure and Isothermal Oxidation at 800, 1200, and 1300 °C of the Al-25.5Nb-6Cr-0.5Hf (at %) Alloy

Hernández-Negrete

Tsakiropoulos

2019

Materials

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Nb-silicide-based alloys have the potential to replace Ni-based superalloys in future aero engines to enable the latter to meet environmental and performance targets. These new alloys, like the Ni-based superalloys that are currently used, will require environmental protection with a coating system that should be chemically compatible with the substrate. A challenge for alloy development is to discover αAl2O3 scale forming coating alloys and in particular to find out whether such alloys could be “compatible” with other coating alloys for environmental coating systems for the Nb-silicide-based alloys. This paper focuses on these challenges. The alloy Al-25.5Nb-6Cr-0.5Hf (at %) was studied in the cast and heat-treated (1400 °C) conditions and after isothermal oxidation for 100 h in air at 800, 1200 and 1300 °C. The microstructure consisted of the alloyed NbAl3 and C14-NbCr2 compounds, both of which were stable at least up to 1400 °C, a eutectic of the two compounds and very small volume fractions of (Cr,Al,Nb)ss and HfO2. The prior eutectic microstructure was stable at T ≤ 1200 °C and the solid solution was not stable at T < 1200 °C. At 800 °C the alloy did not pest, but exhibited external and internal oxidation, with AlNbO4, CrNbAlO4, and αAl2O3 in the former and deeper oxidation along the NbAl3/Laves phase boundaries in the latter At 1200 and 1300 °C there was only external oxidation and the scale consisted of two layers, the outer was (Al,Cr)NbO4 intermixed with αAl2O3 and the inner was continuous αAl2O3. At all three oxidation temperatures, no Nb2Al was observed below the alloy/scale interface and Hf acted as a reactive element forming HfO2 that enhanced the adhesion of the scale. The alloy exhibited good correlations with αAl2O3 scale forming silicide and silicide + aluminide intermetallic alloys in maps of the parameters (related to atomic size), (related to electronegativity), and VEC (number of valence electrons per atom filled into the valence band) that should assist the design of bond coats that do not pest and form αAl2O3 in their scales.

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“…3. The time constant of growth rate or n value, determined as the exponent in the following equation [21], may be used to characterize oxidation kinetics. 3.…”

Section: Oxidation Of Uncoated In600 In Airmentioning

confidence: 99%

Enhancing the Oxidation Behavior of Zr-Modified Aluminide Coatings on Inconel 600 at Different Temperatures

Dawood

Salim

2022

KEM

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In the recent search nickel superalloy Inconel 600 was coated with Zr-modified aluminide diffusion coating using pack cementation technique. Diffusion coating was done in a single step utilizing a conversion reaction of 10% Al, 2% ZrO2, 4% NaCl, and 84 percent Al2O3 (wt. percent ) and a simultaneous aluminizing-zirconizing process. The diffusion coating operations were performed in an argon environment at 1050 °C for 10 hours. The test of the isothermal oxidation in dry air was performed on the Inconel Alloy 600 (IA600) without and with Zr-modified aluminide coating for 800-1000 °C. The oxidation kinetic of IA600 and its coated system was found to follow the parabolic law. The activation energy is 243 kJ/mol. for the coated system and 457 kJ/mol. for the uncoated system. XRD analysis show that oxide phases are formed on an uncoated IA600 surface during most of the oxidation exposure conditions are NiO, Cr2O3, Fe2O3, NiCr2O4 and NiFe2O4, , whereas alumina scale is the major oxide that is obtained on the surface of coated samples.

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Oxidation Behavior of Hf-Modified Aluminide Coatings on Inconel-718 at 1050°C

Cited by 15 publications

References 67 publications

Review on Nickel Aluminide based Bond Coat Properties and Oxidation Performance for Thermal Barrier Coating (TBC) Application

Review on Nickel Aluminide based Bond Coat Properties and Oxidation Performance for Thermal Barrier Coating (TBC) Application

On the Microstructure and Isothermal Oxidation at 800, 1200, and 1300 °C of the Al-25.5Nb-6Cr-0.5Hf (at %) Alloy

Enhancing the Oxidation Behavior of Zr-Modified Aluminide Coatings on Inconel 600 at Different Temperatures

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