Dominant effect of particle size on the CeO2 preferential evaporation during plasma spraying of La2Ce2O7

Wang, Li-Shuang; Zhang, Shan-Lin; Liu, Tao; Li, Chang-Jiu

doi:10.1016/j.jeurceramsoc.2016.11.020

Cited by 27 publications

(4 citation statements)

References 39 publications

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“…Raw material of Powder 1 was manufactured by chemical co-precipitation, and those of the other Powders 2 and 3 were manufactured by solid state reaction. To achieve stoichiometric coatings in possession of columnar microstructures [27,28], the La/Ce atomic ratios in the three feedstocks were 1.24, 1.11, and 1.48, respectively.…”

Section: Feedstock Fabricationmentioning

confidence: 99%

Section: Microstructure Of Lc Coatingsmentioning

confidence: 99%

“…Taking into consideration of coating morphologies, it may have correlations with higher feedstock evaporation rates. Contrary to vapor deposition, liquid deposition is supposed to reserve more La in the coatings [27]. To further study the local phase compositions of the columns, an FIB specimen was prepared from the center of a column in Coating 3 as illustrated in Figure 7.…”

Section: Composition Of Lc Coatingsmentioning

confidence: 99%

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Correlation of Feedstock Powder Characteristics with Microstructure, Composition, and Mechanical Properties of La2Ce2O7 Coatings Produced by Plasma Spray-Physical Vapor Deposition

Zhao

et al. 2020

Coatings

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By virtue of plasma spray-physical vapor deposition (PS-PVD) process, coatings in possession of columnar structures can be obtained by suitable processing parameters coupled with specially designed powder feedstock. In this paper, the influence of powder characteristics on the La2Ce2O7 (LC) coating microstructures was investigated by using three kinds of feedstock powders with same PS-PVD processing parameters. It was found that small agglomerated feedstock, weak binding strength, and small primary particle sizes can enhance the feedstock evaporation rate, thus obtaining well columnar structured coatings. X-ray diffraction (XRD) patterns revealed that except for a very small amount of La2O3 the main phase of all the coatings is LC. The La/Ce atomic ratios reduced in the coatings compared to the feedstocks, especially the coatings with better columnar structure. Super-lattice patterns were observed by transmission electron microscope (TEM), which means that the LC phase is supposed to be pyrochlore structure. Furthermore, the mechanical properties evaluated by nano-indentation tests indicated that both the hardness and Young’s modulus of each coating show negative correlations with the porosity inside the columns.

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Section: Feedstock Fabricationmentioning

confidence: 99%

Section: Microstructure Of Lc Coatingsmentioning

confidence: 99%

Section: Composition Of Lc Coatingsmentioning

confidence: 99%

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Correlation of Feedstock Powder Characteristics with Microstructure, Composition, and Mechanical Properties of La2Ce2O7 Coatings Produced by Plasma Spray-Physical Vapor Deposition

Zhao

et al. 2020

Coatings

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“…For example, Leger et al [14] adopted experimental and numerical approaches to investigate the powder particle shape effect on the Al-Al 2 O 3 coating build-up mechanism on a multi-scale and their results showed that spherical Al powder is more suitable to obtain better coatings with lower porosity. Wang et al [15] NiCrBSi powder feedstock with particle sizes in a range of 45-109 µm, purchased from the North of New Material Science and Technology Company (Beijing, China), are listed in Table 1. Starting from the as-received NiCrBSi powder, the powder was screened by conventional sieves of different standards (150#, 200# and 300#) in sequence.…”

Section: Introductionmentioning

confidence: 99%

Particle Size-Dependent Microstructure, Hardness and Electrochemical Corrosion Behavior of Atmospheric Plasma Sprayed NiCrBSi Coatings

Sang

Chen

Zhao

et al. 2019

Metals

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Particle size is a critical consideration for many powder coating-related industries since it significantly influences the properties of the produced materials. However, the effect of particle size on the characteristics of plasma sprayed NiCrBSi coatings is not well understood. This work investigates the microstructures, hardness and electrochemical corrosion behavior of plasma sprayed NiCrBSi coatings synthesized using different-sized powders. All coatings mainly consist of Ni, N 3 B, CrB, Cr 7 C 3 and Cr 3 C 2 phases. The coatings produced by small particles (50-75 µm) exhibit lower porosity (2.0 ± 0.8%). Such coatings show a higher fraction (15.5 vol.%) of the amorphous phase and lower hardness (700 HV 0.5 ) than the counterparts (8.7 vol.% and 760 HV 0.5 , respectively) produced by large particles (75-100 µm) with higher porosity (3.0 ± 1.6%). Meanwhile, the coatings produced from smaller particles possess a larger number of non-bonded boundaries, leading to the easier penetration of corrosive medium, as well as a higher corrosion current density (0.254 ± 0.062 µA/cm 2 ) and a lower charge transfer resistance (0.37 ± 0.07 MΩ cm 2 ). These distinctions are attributed to particle size-induced different melting degrees and stackings of in-flight particles during deposition. studied the effects of particle size and structure on the preferential Ce evaporation for La 2 Ce 2 O 7 particles during plasma spraying and indicated that the evaporation loss of Ce is significantly influenced by particle size, thereby affecting the properties of the as-sprayed La 2 Ce 2 O 7 coatings. Sun et al. [16] used different-sized WC powders to sinter three sets of WC-8Co cemented carbides and found that the transgranular fractures of the prepared cemented carbides are more evident with increasing WC particle size. From all this one can conclude that powder appearance potentially influences the properties and therefore the end applications of the produced products.NiCrBSi alloy coatings are also commonly prepared by metallic powder-related techniques including spraying [17,18] and laser cladding [19,20], with the aim to produce barriers to protect substrates from wear and/or corrosion. Amongst these techniques, atmospheric plasma spraying (APS) is frequently used due to its high synthesis speed and few limitations on equipment [21]. APS adopts a plasma gun as a heat source to melt the feedstock powder sprayed from the nozzle and impinges these powder particles on the substrates in a layer by layer method [22]. As a result, this processing method results in a typical lamellar microstructure in APS-prepared NiCrBSi coatings associated with a large number of pores and non-bonded boundaries (including lamellar boundaries and particle boundaries). Pores generally decrease the cohesion of the as-sprayed NiCrBSi coatings, thereby reducing their hardness and wear resistance [22]. In the meantime, non-bonded boundaries in as-sprayed NiCrBSi coatings provide diffusion paths for the ingress of corrosive species in a corrosive environment [22]. ...

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Life and FCT Failure of Yttria- and Ceria-Stabilized EBPVD TBC Systems on Ni-Base Substrates

Fritscher

2018

Oxid Met

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The lifetime at 1100°C of furnace oxidation tested TBC samples having YSZ (ZrO 2-7 wt% Y 2 O 3) and CeSZ (ZrO 2-25 wt% CeO 2-2.5 wt% Y 2 O 3) topcoats on four Ni base alloys including a no-bond coat NiCrAl alloy were studied. The thermally grown oxide (TGO) was investigated by energy dispersive spectroscopy. The outer zone of the TGO revealed preferred enrichment of Zr and of rare earth elements Ce and Y in dependence of the stage of life. The oxygen potential gradients in the TGO have been rated; they are stronger for the YSZ TBC systems than for the CeSZ systems and cause a more intensive interaction of the outer zone alias mixed zone with the metal substrate than with the ceramic topcoat. When comparing the chemical composition data of the mixed zone as a function of the test period, the average lifetime as well as the particular composition of the two topcoats and the refractory element content of the substrates allowed conclusions to be drawn about the mechanisms which influence the lifetime.

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Dominant effect of particle size on the CeO2 preferential evaporation during plasma spraying of La2Ce2O7

Cited by 27 publications

References 39 publications

Correlation of Feedstock Powder Characteristics with Microstructure, Composition, and Mechanical Properties of La2Ce2O7 Coatings Produced by Plasma Spray-Physical Vapor Deposition

Correlation of Feedstock Powder Characteristics with Microstructure, Composition, and Mechanical Properties of La2Ce2O7 Coatings Produced by Plasma Spray-Physical Vapor Deposition

Particle Size-Dependent Microstructure, Hardness and Electrochemical Corrosion Behavior of Atmospheric Plasma Sprayed NiCrBSi Coatings

Life and FCT Failure of Yttria- and Ceria-Stabilized EBPVD TBC Systems on Ni-Base Substrates

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