Self-diffusion in α-Al2O3 and growth rate of alumina scales formed by oxidation: effect of Y2O3 doping

Gall, Marián; Huntz, A.M.; Lesage, B.; Monty, C.; Bernardini, J.

doi:10.1007/bf00352151

Cited by 83 publications

(45 citation statements)

References 30 publications

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“…According to some published work, if large Y-oxides form in the alumina scale, the growth rate of the alumina scale will increase due to an increase of the inward diffusion of oxygen along grain boundaries [67][68][69]. However, if no large Y-oxides form, doping some yttrium in the alumina scale can decrease the grain-boundary diffusion of cations, resulting in a slower oxidation rate [70,71].…”

Section: Surface Oxidationmentioning

confidence: 99%

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

Yuan

Peng

et al. 2015

Surface and Coatings Technology

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Abstract. MCrAlY coatings are widely used to protect superalloys against oxidation and corrosion at high temperature in gas turbine engines. To design a durable MCrAlY coating, the behaviour of alloying elements in coating-superalloy system needs to be better understood. After oxidation tests in temperature range between 900 °C to 1100 °C, the development of the microstructures in the samples was analysed at the coating surface or in areas near the coatingsuperalloy interface. Some interdiffusion simulations were also done to model the diffusion behaviour of alloying elements in different coating-superalloy couples. The results show that both oxidation at the coatings' surface and the elements' diffusion inside of the materials were temperature-and chemical-composition dependent. The behaviour of some minor elements like Y, Hf, Ru and Ir in the oxidation processes was particularly studied by tracking their position and composition in the materials.

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Section: Surface Oxidationmentioning

confidence: 99%

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

Yuan

Peng

et al. 2015

Surface and Coatings Technology

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“…Small amounts of so-called reactive elements (RE) such as Y, Zr, Hf, Ce, and La are usually added to the alloys to improve the oxidation properties. It has been reported that the RÉ s decrease the oxide growth rate, enhance selective oxidation and, especially, improve scale adherence [1][2][3][4][5][6][7][8][9]. Most of the research on the oxidation properties of FeCrAl alloys concerns temperatures [1,000°C.…”

Section: Introductionmentioning

confidence: 99%

The Oxide Scales Formed on a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy at 900 °C in O2 and in O2 + H2O

et al. 2015

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Early oxide scale growth on an oxide dispersion strengthened rapidly solidified powder FeCrAl material, Kanthal Ò APMT, was investigated at 900°C in an O 2 ? N 2 and an O 2 ? H 2 O ? N 2 environment for up to 168 h. Gravimetry was used to follow oxide growth and the oxide scale was examined with XRD. Scale morphology was investigated in detail with SEM/EDX, TEM/EDX/CBED. The alloy rapidly formed a protective two-layered a-alumina scale containing oxide nodules. Between the top and bottom alumina layers there was a zone containing chromia-rich particles 5-20 nm in diameter, corresponding to the original sample surface. The alumina scale mainly grew inward after 1 h of oxidation. Alumina scale growth at 900°C was initially somewhat faster in an O 2 ? H 2 O ? N 2 environment than in an O 2 ? N 2 environment.

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“…The grain boundary diffusivity in reference [16] was observed to be as much as three orders of magnitude lower for an alpha alumina doped with 300 ppm Y as compared with the undoped alumina. The Y 3+ ions at the grain boundary were believed to have caused this reduced diffusivity.…”

Section: (Ii)mentioning

confidence: 92%

“…Some diffusion data for Al and O ions in alpha alumina are relevant here. Studies using radio-active tracers [16] indicate that the lattice diffusion in undoped alpha alumina is about 6 orders of magnitude smaller than grain boundary diffusion. Therefore, one anticipates that grain boundaries would be the primary path by which oxygen is carried through the alumina to the bond-coat.…”

Section: The Alumina Sublayer Architecturementioning

confidence: 99%

Advanced Thermal Barrier Coating

Bhattacharya¹

2000

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Self-diffusion in α-Al2O3 and growth rate of alumina scales formed by oxidation: effect of Y2O3 doping

Cited by 83 publications

References 30 publications

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

Some aspects of elemental behaviour in HVOF MCrAlY coatings in high-temperature oxidation

The Oxide Scales Formed on a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy at 900 °C in O2 and in O2 + H2O

Advanced Thermal Barrier Coating

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