Hot Corrosion Behavior of Double-ceramic-layer LaTi2Al9O19/YSZ Thermal Barrier Coatings

Xie, Xiaoyun; Guo, Hongbo; Gong, Shengkai; Xu, Huibi

doi:10.1016/s1000-9361(11)60372-5

Cited by 42 publications

(9 citation statements)

References 22 publications

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“…These thick [Ni, Co, Cr] x O y mixed oxides layer spalled off due to thermal stress induced by large CTE (coefficient of thermal expansion) mismatch between oxide and IN792 during cyclic cooling, as illustrated in Figure C. Due to a high affinity of Al and Cr, the basic fluxing removes both Al and Cr from the corrosion front of the metal surface. As a result, an Al‐ and Cr‐depletion zone formed at the edge of the coating (marked in green in Figure D) near the corrosion front.…”

Section: Resultsmentioning

confidence: 99%

Failure mechanism of MCrAlY coating at the coating‐substrate interface under type I hot corrosion

Zhang

Peng

2019

Materials & Corrosion

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MCrAlY coatings are widely used to provide protection of hot component in modern gas turbine engines against high‐temperature oxidation and hot corrosion. Coating‐substrate interface, where the substrate is only partially covered by the coatings, is vulnerable to the hot corrosion attack. The accelerated degradation at the coating‐substrate interface can cause fast spallation of the coating, leading to the early failure of the gas turbine components. In this paper, MCrAlY powder was deposited on IN792 disks by high‐velocity oxygen‐fuel spraying. The hot corrosion behavior of the coated sample was investigated using (0.8Na, 0.2K)2SO 4 salt deposition at 900°C in lab air. Results showed a minor attack in the coating center, however, an accelerated corrosion attack at the coating‐substrate interface. The fast growth of corrosion products from substrate caused large local volume expansions at the coating‐substrate interface, resulting in an early coating spallation.

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Section: Resultsmentioning

confidence: 99%

Failure mechanism of MCrAlY coating at the coating‐substrate interface under type I hot corrosion

Zhang

Peng

2019

Materials & Corrosion

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“…8 Deposition of sodium chlorides onto the turbine blades from air or sea water contamination, combined with the gaseous sulphur oxides during service, can cause hot corrosion attack of TBCs. 9 At high temperatures, Al in the bond coat can be oxidised preferentially and forms a thin and dense Al 2 O 3 layer (TGO). This TGO layer acts as a diffusion barrier and substantially reduces the degradation rate of the substrate.…”

Section: Introductionmentioning

confidence: 99%

Comparison of hot corrosion behaviour of FGM and usual TBCs

Rahnavard

Ghorabi

Rafiee

2017

Surface Engineering

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In the present paper, hot corrosion behaviour of functionally graded material (FGM) and usual ceria-yttria stabilised zirconia (CYSZ) TBCs, prepared by atmospheric plasma spraying method was evaluated. In addition, coating microstructures were investigated using scanning electron microscope; EDS and X-ray diffraction techniques before and after hot corrosion test. The results showed, due to different corrosion mechanisms, the life of FGM TBC was higher than the usual one. The degradation mechanism of usual TBC was formation of TGO at the bond coat/ CYSZ layer interface resulted in delamination, while in FGM coating was the stress induced by phase transformation volume increment occurred in the coating and the thermal stress accompanied by thermal expansion mismatch.

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“…Thus, to evaluate the same, the porosity level in YSZ top coat is varied, ~22% for high porosity and ~3% for low porosity samples. Although hot corrosion behavior of YSZ-based TBCs has been widely investigated at higher temperatures of 800°C-1100°C, 9,[31][32][33] only few studies are available in literature performed at lower temperatures (<800°C). The understanding of hot corrosion behavior of TBCs at lower temperatures is crucial for diesel engine applications.…”

Section: Introductionmentioning

confidence: 99%

Hot Corrosion of Stabilized Zirconia Thermal Barrier Coatings and the Role of Mg Inhibitor

et al. 2015

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The 3-4 mol% yttria-stabilized zirconia (YSZ) is widely used as a material for thermal barrier coating; however, the corrosive constituents present in fuel typically result in mechanical disintegration of YSZ coatings. The 3-4 mol% YSZ coatings with respective porosity of~3% and~22% have been undertaken with the objective to compare the hot corrosion behavior in air and sulfur-rich atmospheres. The coatings are kept in contact with V 2 O 5 + MgO powder mixture at 750°C for different dwell times of 24 and 76 h. The samples kept in air have shown intact YSZ layer for both the coatings, whereas a delamination of YSZ layer is observed for high porosity sample kept in sulfur-rich atmosphere. XRD patterns of all the samples treated in sulfur-rich atmosphere have indicated a phase transformation in YSZ from tetragonal to monoclinic. However, no such phase transformation has been found for samples treated in air. The V 2 O 5 -induced hot corrosion attack on YSZ coating in air has been successfully inhibited by MgO, which forms a thermally stable Mg 3 V 2 O 8 compound. However, in sulfur-rich atmosphere, MgO is partially consumed to form sulfates, which allows certain fraction of V 2 O 5 to react with Y 2 O 3 causing the degradation of top coat.

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Hot Corrosion Behavior of Double-ceramic-layer LaTi2Al9O19/YSZ Thermal Barrier Coatings

Cited by 42 publications

References 22 publications

Failure mechanism of MCrAlY coating at the coating‐substrate interface under type I hot corrosion

Failure mechanism of MCrAlY coating at the coating‐substrate interface under type I hot corrosion

Comparison of hot corrosion behaviour of FGM and usual TBCs

Hot Corrosion of Stabilized Zirconia Thermal Barrier Coatings and the Role of Mg Inhibitor

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