Isothermal oxidation of air plasma spray NiCrAlY bond coatings

Choi, Hanshin; Yoon, Byoung-Hyun; Kim, Hyungjun; Lee, Changhee

doi:10.1016/s0257-8972(01)01557-2

Cited by 121 publications

(46 citation statements)

References 13 publications

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“…10. From the cross-sectional morphology of the interfaces between CoNiCrAlY coatings and substrates after 1000 h exposure, the intergranular voids present in the scale which may be formed, as described by Choi (Choi et al, 2002). In the absence of the effective sinks for vacancies, vacancies generated by outward diffusion of alloying elements such as Ni or Co condense to form cavities.…”

Section: Effect Of Particle Distribution On the Porosity Of Coatingsmentioning

confidence: 99%

“…The square value of TGO thickness was proportional to the square root of exposure time, and the square value of weight gain was proportional to the heat exposure time. The oxidation can be divided into two stages (Choi et al, 2002). One is the transient oxidation stage which shows initial relatively rapid oxidation rate and the other is the steady-state oxidation stage which shows a relatively slow oxidation rate.…”

Section: Effect Of Particle Distribution On the Porosity Of Coatingsmentioning

confidence: 99%

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Isothermal Oxidation Behavior of Plasma Sprayed MCrAlY Coatings

Seo¹,

Ogawa²

2012

Advanced Plasma Spray Applications

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Section: Effect Of Particle Distribution On the Porosity Of Coatingsmentioning

confidence: 99%

Section: Effect Of Particle Distribution On the Porosity Of Coatingsmentioning

confidence: 99%

Isothermal Oxidation Behavior of Plasma Sprayed MCrAlY Coatings

Seo¹,

Ogawa²

2012

Advanced Plasma Spray Applications

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“…Premature failure of TBCs during thermal cycling is still a critical problem, which limits the lifetime of the coated components ( Ref 7). This failure mainly occurs by delamination of the top coat ( Ref 8,9). The cracks leading to delamination nucleate and propagate at the topbond coat interface.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Heat Treatment on the Oxidation Behavior of HVOF and VPS CoNiCrAlY Coatings

2009

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Free-standing VPS and HVOF CoNiCrAlY coatings were produced. The as-sprayed HVOF coating retained the c/b microstructure of the feedstock powder, and the VPS coating consisted of a single (c) phase. A 3-h, 1100°C heat treatment in vacuum converted the single-phase VPS coating to a two-phase c/b microstructure and coarsened the c/b microstructure of the HVOF coating. Oxidation of freestanding as-sprayed and heat-treated coatings of each type was carried out in air at 1100°C for a duration of 100 h. Parabolic rate constant(s), K p , were determined for free-standing, as-sprayed VPS and HVOF coatings as well as for free-standing coatings that were heat treated prior to oxidation. The observed increase in K p following heat treatment is attributed to a sintering effect eliminating porosity from the coating during heat treatment. The lower K p values determined for both HVOF coatings compared to the VPS coatings is attributed to the presence of oxides in the HVOF coatings, which act as the barrier to diffusion. Oxidation of the as-sprayed coatings produced a dual-layer oxide consisting of an inner a-Al 2 O 3 layer and outer spinel layer. Oxidation of the heat-treated samples resulted in a singlelayer oxide, a-Al 2 O 3 . The formation of a thin a-Al 2 O 3 layer during heat treatment appeared to prevent nucleation and growth of spinel oxides during subsequent oxidation.

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“…la capa de enganche durante la oxidación del recubrimiento (17). De forma general, en el análisis de esta muestra se puede observar que las sales y los productos generados en las distintas reacciones, penetraron en la capa cerámica e incluso llegaron hasta la capa de anclaje metálico, propiciando nuevas reacciones de desestabilización.…”

Section: Degradación De Barreras Térmicas Por Sales Fundidasunclassified

Degradación de barreras térmicas por sales fundidas

Utrilla¹,

Poza²,

Gómez-García³

et al. 2008

Bol. Soc. Esp. Ceram. Vidr.

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Las barreras térmicas son sistemas multicapa que se aplican a sustratos metálicos para mejorar su resistencia a la temperatura. El material utilizado en el trabajo es un sustrato base níquel (Inconel 600) con recubrimiento multicapa de NiCrAlY y ZrO 2 parcialmente estabilizada con Y 2 O 3 (Y-PSZ) depositado por plasma atmosférico. La presencia de contaminantes, como S, V o Na presentes en combustibles de baja calidad, puede dar lugar a reacciones con este óxido estabilizador de la circona (Y 2 O 3 ), originando una desestabilización estructural de la circona por disminución del contenido en itria. En esta comunicación se ha realizado un estudio sistemático de la degradación del material frente a determinados agentes corrosivos a elevada temperatura. Sobre la superficie de las muestras se añadieron mezclas de 40% Na 2 SO 4 -60% V 2 O 5 y se trataron isotérmicamente a 800 ºC durante 48 y 144 horas. Finalmente, se evaluó la modificación de las propiedades por efecto de los agentes agresivos. Mediante la técnica de espectroscopía de impedancia electroquímica (EIS) se estimó la degradación de la barrera térmica. El estudio de la evolución microestructural se realizó mediante técnicas de microscopía óptica (MO), electrónica de barrido ambiental (ESEM) y difracción de rayos X (DRX). Palabras clave: Barreras térmicas, sales fundidas, proyección por plasma atmosférico, microscopía electrónica de barrido, espectroscopia de impedancia electroquímica. Corrosion of thermal barrier coating by molten salts.Thermal barrier coatings (TBC) are frequently used to provide thermal insulation to metallic components. The material used in this investigation comprises a ceramic top layer, ZrO 2 8Y 2 O 3 (Y-PSZ), and an overlay coating, Ni22Cr10Al1Y, air plasma sprayed on to a nickel base alloy Inconel 600 substrate. Yttria stabilizes the cubic phase zirconia, but it can react with S, V and Na contaminants contained in many low-quality industrial fuels. A decrease in the yttria content promotes the transformation to monoclinic ZrO 2 . The materials were subjected to an isothermal air furnace test under 40% Na 2 SO 4 -60% V 2 O 5 mixtures at 800 ºC for 48 and 144h. The degradation of the coating was analyzed by electrochemical impedance spectroscopy (EIS). The microstructure was characterized by enviromental scanning electron microscopy (ESEM), X-ray microanalysis (EDX) and x ray diffracction (XRD).

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Isothermal oxidation of air plasma spray NiCrAlY bond coatings

Cited by 121 publications

References 13 publications

Isothermal Oxidation Behavior of Plasma Sprayed MCrAlY Coatings

Isothermal Oxidation Behavior of Plasma Sprayed MCrAlY Coatings

The Effect of Heat Treatment on the Oxidation Behavior of HVOF and VPS CoNiCrAlY Coatings

Degradación de barreras térmicas por sales fundidas

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