A high performance NiCoCrAlY bond coat manufactured using laser powder deposition

Luo, Lirong; Shan, Xiao; Zou, Zhi; Zhao, Xiaofeng; Wang, Xin M.; Zhang, Aiping; Guo, Fangwei; Xiao, Ping

doi:10.1016/j.corsci.2017.07.018

Cited by 52 publications

(32 citation statements)

References 42 publications

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“…Upon cooling, high levels of residual stress develop in the thermally grown oxide (TGO), primarily because of its thermal expansion misfit with the metal substrate. The large stress and the associated strain energy in the TGO could motivate spallation once a certain thickness is reached (the elastic strain energy scales with the TGO thickness) [3]. Meanwhile, the MCrAlY/TGO interfacial toughness decreases with thermal exposure, mainly induced by detrimental sulfur segregation to the interface and the growth of imperfections (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…In the areas where Y-Al inclusions are absent, the TGO consists of an equiaxed outer layer and a columnar inner layer. The duplex structure of the TGO results from the concurrent inward oxygen diffusion and outward aluminum diffusion[3,12]. In the areas where relatively large Y-Al inclusions are present, a thicker TGO and a mixed structure of equiaxed and columnar grains are identified.…”

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confidence: 99%

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Significantly improving the oxidation and spallation resistance of a MCrAlY alloy by controlling the distribution of yttrium

et al. 2019

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The NiCoCrAlY alloy with uniform yttrium distribution was fabricated via powder milling and spark plasma sintering. After powder milling, yttrium was uniformly distributed in the alloy in the form of Ni-Y precipitates (50 to 150 nm) and nano-sized Y 2 O 3 particles (5 to 30 nm). It was found that the uniform yttrium distribution could: 1) lower thermally grown oxides (TGO) growth rate; 2) reduce the growth stress in the TGO; 3) suppress S segregation to the interface and the formation of interfacial imperfections (e.g. oxide intrusions, pores). Consequently, the oxidation and spallation resistance of the TGO was significantly improved.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Significantly improving the oxidation and spallation resistance of a MCrAlY alloy by controlling the distribution of yttrium

et al. 2019

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“…Indeed, during prolonged oxidation testing, a significant reduction of the average weight gain was attained for the oxidized nanocrystalline MCrAlY coatings. Deviation from parabolic behavior may be related to the control or inhibition of the diffusion process by the formation of slow-growing and dense α-Al 2 O 3 rather than other transient oxides and spinels 51 . The deviation from parabolic rate law for the nanostructured MCrAlY coatings has also been reported elsewhere 23 .…”

Section: Resultsmentioning

confidence: 99%

A comprehensive study on the microstructure evolution and oxidation resistance of conventional and nanocrystalline MCrAlY coatings

Ghadami

Rouhaghdam

Ghadami

2021

Sci Rep

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Conventional and nanocrystalline MCrAlY coatings were applied by the high-velocity oxy-fuel (HVOF) deposition process. The ball-milling method was used to prepare the nanocrystalline MCrAlY powder feedstock. The microstructure examinations of the conventional and nanocrystalline powders and coatings were performed using X-ray diffraction (XRD), high-resolution field emission scanning electron microscope (FESEM) equipped with energy-dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). Williamson–Hall analyzing method was also used for estimation of the crystalline size and lattice strain of the as-milled powders and sprayed coatings. Owing to the investigation of the oxidation behavior, the freestanding coatings were subjected to isothermal and cyclic oxidation testing at 1000 and 1100 °C under static air. The results showed that the conventional as-sprayed MCrAlY coating had a parabolic behavior in the early stage and prolonged oxidation process. On the contrary, in the case of the nanocrystalline MCrAlY coating, the long-term oxidation behavior has deviated from parabolic to sub-parabolic rate law. Moreover, the results also exemplified that the nanocrystalline MCrAlY coating had a greater oxidation resistance following the creation of a continuous and slow-growing Al2O3 scale with a fine-grained structure. The nucleation and growth mechanisms of the oxides formed on the nanocrystalline coating have also been discussed in detail.

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“…In fact, the composition and growth rate of the TGO layer varies according to the coating properties such as the chemical composition, microstructure, and oxides content [8]. These coatings have been manufactured by methods of physical vapor deposition (PVD) [9], magnetron sputtering [10], arc ion plating (AIP) [11], thermal spraying [12][13][14][15] and laser powder deposition (LPD) [16]. The MCrAlY coatings deposited using the HVOF process often have better properties in comparison to the other thermal spraying methods and in some cases provided higher oxidation resistance [17,18].…”

Section: Introductionmentioning

confidence: 99%

Study on production of modified MCrAlY powder with nano oxide dispersoids as HVOF thermal spray feedstock using mechanical milling

Zakeri

Ghadami

Rouhaghdam

et al. 2020

Mater. Res. Express

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This paper investigates NiCoCrAlY-CeO 2 nanocomposite powders prepared by mechanical milling process. At first, micron-sized ceria powder was pre-milled to obtain nano-sized powders and then 1 wt% CeO 2 was mixed with the conventional NiCoCrAlY powder and milled under three sets of parameters. The conventional and milled powders were deposited on low carbon steel substrates by HVOF thermal spray technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), fieldemission scanning electron microscopy (FESEM) and image analyzing method were used to characterize the prepared powders and coatings. Microstructural characterization showed that the milled powders underwent morphological and phase transitions. Through the microstructural and compositional analyses, it was found that a homogeneous distribution of CeO 2 nano-dispersoids in the NiCoCrAlY matrix was obtained. The resulting coatings showed that by using optimized milling parameters, required particle size and suitable morphology for thermal spray can be achieved.

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A high performance NiCoCrAlY bond coat manufactured using laser powder deposition

Cited by 52 publications

References 42 publications

Significantly improving the oxidation and spallation resistance of a MCrAlY alloy by controlling the distribution of yttrium

Significantly improving the oxidation and spallation resistance of a MCrAlY alloy by controlling the distribution of yttrium

A comprehensive study on the microstructure evolution and oxidation resistance of conventional and nanocrystalline MCrAlY coatings

Study on production of modified MCrAlY powder with nano oxide dispersoids as HVOF thermal spray feedstock using mechanical milling

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