The effect of silicon on thermal shock performance of aluminide-thermal barrier coatings

Shirvani, Kourosh; Mastali, Sadegh; Rashidghamat, A.; Abdollah-Pour, Hassan

doi:10.1016/j.corsci.2013.05.025

Cited by 35 publications

(14 citation statements)

References 26 publications

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“…The TGO layer rich in Al 2 O 3 with small amounts of NiO and Cr 2 O 3 with a thickness of about 3 to 3.5 μm was formed during the thermal spray process on the surface of the Pt-Al layer. Formation of this layer was also observed by Shirvani et al in thermal spray of YSZ [24].…”

Section: Microstructure Of Tbcsupporting

confidence: 77%

Microstructural evolution and cyclic oxidation of Pt-Al-YSZ coating under thermal shock

Rabieifar¹,

Nategh²,

Afshar³

et al. 2020

Mater. Res. Express

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In this research, the effect of thermal shock has been investigated on the microstructure and cyclic oxidation of Pt-Al-7%YSZ coating applied on Rene-80 superalloy. The microstructural evaluation and phase identification were performed by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD). The thermal shock test consisted of repeated cycles of rapid cooling between 900°C and 400°C. Prior to the thermal shock test, the specimen coated by Pt-electroplating, high-activity low-temperature (HALT) aluminizing and the thermal spray of YSZ ceramic layer. From surface towards the substrate; the coating consisted of 5 layers including: 7% YSZ, PtAl 2 +β-(Ni,Pt)Al, β-(Ni,Pt)Al with fine precipitates rich in α-(Cr) and α-(W), precipitate-free β-NiAl, and inter-diffusion zone next to the specimen surface. After the thermal shock test, spallation and delamination have been observed in the YSZ layer. The Pt-Al layer was found in upper and lower parts of the coating with different Pt concentration. Also, the chemical composition of the Pt-Al layer demonstrated the removal of PtAl 2 particles and β transformation to both γ and γ′ phases. Degradation of Pt-Al layer occurred by ratcheting the thermally grown oxide (TGO), rumpling, and cavitation. Comparison of weight changes showed that the thermal shock resistance is improved by Pt-Al-7% YSZ coating.

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Section: Microstructure Of Tbcsupporting

confidence: 77%

Microstructural evolution and cyclic oxidation of Pt-Al-YSZ coating under thermal shock

Rabieifar¹,

Nategh²,

Afshar³

et al. 2020

Mater. Res. Express

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“…Oxides of group-IIIB elements have a variety of important applications. Corundum structure Al 2 O 3 , or α-Al 2 O 3 , is used as substrates for GaN-based light-emitting diodes [1], optical waveguides [2], gate insulators [3], oxidation and corrosion protective scales [4], thermal barrier coatings [5], tritium permeation barriers in future fusion reactors [6], and so forth. The θ -Al 2 O 3 phase is isostructural with the monoclinic β-gallia structure and is used as the Pt atom support in CO [7] and NO [8] oxidation catalysts.…”

Section: Introductionmentioning

confidence: 99%

Band alignment at surfaces and heterointerfaces ofAl2O3,Ga2O3,
Hinuma
¹
,
Gake
²
,
Oba
³

2019
Phys. Rev. Materials
38
4
21
0
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The band alignments at nonpolar surfaces and heterointerfaces of Al 2 O 3 , Ga 2 O 3 , and In 2 O 3 polymorphs, and three related group-III oxides, namely, Sc 2 O 3 , Y 2 O 3 , and La 2 O 3 , are investigated by using first-principles calculations. A non-self-consistent dielectric-dependent hybrid functional approach is adopted on top of semilocal density-functional calculations by using the Perdew-Burke-Ernzerhof functional tuned for solids (PBEsol) to accelerate the band alignment evaluation that involves surface and interface calculations. Among the five crystal structures considered, namely, corundum, β-gallia, κ-alumina, bixbyite (C-type rare earth), and A-type rare earth, the lowest energy phases are corundum, β-gallia, A-type rare earth, and bixbyite for Al 2 O 3 , Ga 2 O 3 , La 2 O 3 , and the others, respectively, within PBEsol calculations. The ionization potential typically decreases in the order Al 2 O 3 , Ga 2 O 3 , In 2 O 3 , Sc 2 O 3 , Y 2 O 3 , and La 2 O 3 within the same crystal structure and surface termination. This tendency is enhanced by the atomic relaxation-induced surface dipoles, where smaller cations tend to relax toward the bulk side compared to O ions, while larger cations tend to relax toward the vacuum side. The ionization potential and electron affinity differences at unrelaxed surfaces are good indicators of the interfacial valence-and conduction-band offsets, respectively, for Al 2 O 3 /Ga 2 O 3 with a relatively small mismatch in the lattice parameters of the two phases.

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“…Furthermore, the precipitation strengthening of alloy induced by precipitates and carbides is accompanied by sacrificing the corrosion resistance at high temperature in stainless steels and superalloys [15,16]. In order to enhance their resistance to oxidation and vulcanization at high temperature, a thermal barrier coating muse be added in the superalloys [17]. In the present work, electropulsing promoted the formation of 3 grain boundary that compensated the losses of corrosion resistance due to the formation of  particles.…”

Section: Resultsmentioning

confidence: 97%

Electropulsing-induced strengthening of steel at high temperature

Zhang

Qin

2014

Philosophical Magazine Letters

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Electropulsing usually reduces the stability of metastable phases in materials. This work reports the opposite effect, where electropulsing drives the stable -phase at high temperature to be decomposed. This enables both γ-phase and σ-phase in duplex stainless steel to survive and hence to strengthen the steel at high temperature. The hardness of the quenched sample after electropulsing is 49.4% higher than that without electropulsing treatment. The scientific understanding to the observation has been developed.

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The effect of silicon on thermal shock performance of aluminide-thermal barrier coatings

Cited by 35 publications

References 26 publications

Microstructural evolution and cyclic oxidation of Pt-Al-YSZ coating under thermal shock

Microstructural evolution and cyclic oxidation of Pt-Al-YSZ coating under thermal shock

Band alignment at surfaces and heterointerfaces ofAl2O3,Ga2O3,
Hinuma
¹
,
Gake
²
,
Oba
³

2019
Phys. Rev. Materials
38
4
21
0
View full text Add to dashboard Cite

Electropulsing-induced strengthening of steel at high temperature

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The effect of silicon on thermal shock performance of aluminide-thermal barrier coatings

Cited by 35 publications

References 26 publications

Microstructural evolution and cyclic oxidation of Pt-Al-YSZ coating under thermal shock

Microstructural evolution and cyclic oxidation of Pt-Al-YSZ coating under thermal shock

Band alignment at surfaces and heterointerfaces ofAl2O3,Ga2O3,Hinuma1, Gake2, Oba3 2019Phys. Rev. Materials384210View full textAdd to dashboardCite

Electropulsing-induced strengthening of steel at high temperature

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Product

Resources

About

Band alignment at surfaces and heterointerfaces ofAl2O3,Ga2O3,
Hinuma
¹
,
Gake
²
,
Oba
³

2019
Phys. Rev. Materials
38
4
21
0
View full text Add to dashboard Cite