Investigation of High Emissivity Coatings Prepared by Plasma Spraying

In this study, the feedstock powder for plasma spray was prepared by spray drying and post-sintering at 1360 °C using raw metal oxides. The high emissivity coating was deposited by air plasma spraying (APS). The microstructure, phase structure, flowability and bulk density of the plasma sprayed powder were characterized. The microstructure, bond strength and infrared emissivity of the high emissivity coating were also analyzed in this paper. The results reveal that the feedstock powder present good flowability of 42.36 (sp50g) with the bulk density of 1.94 gpml and is suitable for plasma spraying. A dense coating with the bond strength of 39.6MPa and the porosity less than 5 percent was prepared successfully. The normal emissivity of the coating in all waveband is 0.88 at 300°C and 0.87 at 600°C.

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Preparation and Investigation of High Emissivity Coatings Prepared by Plasma Spraying

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.512-515.1062 ◽

2012 ◽

Vol 512-515 ◽

pp. 1062-1065 ◽

Cited By ~ 1

Author(s):

Can Wang ◽

Quan Sheng Wang ◽

Xian Kai Sun

Keyword(s):

Bond Strength ◽

Plasma Spraying ◽

Raw Materials ◽

Air Plasma ◽

Before And After ◽

Plasma Sprayed ◽

Plasma Spraying Process ◽

Normal Emissivity ◽

Spraying Process ◽

High Emissivity

The high emissivity coating was deposited by Air Plasma Spraying (APS). Ni2O3, Cr2O3 were the main raw materials in this study. The feedstock powder was prepared by spray drying and post-sintering at 1420 °C for 2hours. The microstructure, phase structure, flowability and bulk density of the plasma sprayed powder were characterized. The microstructure, bond strength and infrared emissivity of the high emissivity coating were also analyzed in this paper. The results reveal that the powder before and after sintering presents good flowability and is suitable for plasma spraying process. A dense coating with the bond strength of 28.14MPa was prepared successfully. The normal emissivity of the coating in all waveband is 0.87 at the temperature of 300°C, 600°C, 900°C, 1000°C, 1100°C and 1200°C

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Microstructure and Oxidation Behavior of Molybdenum Disilicide Coating Prepared by Air Plasma Sprayed

Materials Science Forum ◽

10.4028/www.scientific.net/msf.686.583 ◽

2011 ◽

Vol 686 ◽

pp. 583-588 ◽

Cited By ~ 2

Author(s):

Jian Hui Yan ◽

Si Wen Tang ◽

Jian Guang Xu

Keyword(s):

Plasma Spraying ◽

Gas Turbines ◽

Hexagonal Lattice ◽

Molybdenum Disilicide ◽

Temperature Structure ◽

Air Plasma ◽

Air Plasma Spraying ◽

Plasma Sprayed ◽

Molybdenum Disilicide Coating ◽

Oxidation Behaviors

Intermetallics molybdenum dislicied has a great potential as a protective coating in aircraft engines and gas turbines in the elevated temperature. The suit for plasma spraying MoSi2powders were prepared by spray drying process and vacuum sintered. The oxidation behaviors of the coating were determined at 1200 °C. The coatings as sprayed and oxidized were characterized by XRD, SEM and EDS. Results show that the flow ability and loose density of MoSi2powder by sintered treatment, were 17.1 s/50g and 2.1g/cm3, respectively, ideal for air plasma spraying. During the course of spraying, some of molybdenum disilicide with a tetragonal lattice was converted into molybdenum disilicide with a hexagonal lattice. Also, part of MoSi2 phase oxidized and transformed to Mo5Si3phase. A relative dense molybdenum disilicide coating was prepared by air plasma spraying. A protective SiO2layer, seems to be glassy, with a thickness about 10 μm was formed on the surface of MoSi2coating during MoSi2coating oxidized at 1200°C for 200 h. The results of the oxidation tests show that MoSi2coating prepared by air plasma spraying may be provide a protect layer for high temperature structure material.

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Preparation and properties of high emissivity Fe–Mn–matrix coatings by air plasma spraying

Materials Research Innovations ◽

10.1179/1432891715z.0000000001511 ◽

2015 ◽

Vol 19 (sup4) ◽

pp. S29-S33 ◽

Cited By ~ 3

Author(s):

Hao Wang ◽

Xianjin Ning ◽

Quansheng Wang ◽

Yanbo Liu ◽

Yuting Song

Keyword(s):

Plasma Spraying ◽

Air Plasma ◽

Air Plasma Spraying ◽

High Emissivity

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Optimization of Yb2O3-Gd2O3-Y2O3 Co-Doped ZrO2 Agglomerated and Calcined Powders for Air Plasma Spraying

Coatings ◽

10.3390/coatings11040373 ◽

2021 ◽

Vol 11 (4) ◽

pp. 373

Author(s):

Zheng Yan ◽

Haoran Peng ◽

Kang Yuan ◽

Xin Zhang

Keyword(s):

Solid Solution ◽

Particle Size ◽

Plasma Spraying ◽

Cubic Phase ◽

Thermal Barrier ◽

Air Plasma ◽

Air Plasma Spraying ◽

Barrier Coating ◽

Controllable Preparation ◽

Co Doped

Yb2O3-Gd2O3-Y2O3 co-doped ZrO2 (YGYZ) is considered to be a promising material in thermal barrier coating (TBC) applications. In this study, 2Yb2O3–2Gd2O3–6Y2O3–90ZrO2 (mol.%) (10YGYZ) feedstock candidates for air plasma spraying (APS) were prepared by calcination of agglomerated powders at 1100, 1200, 1300, 1400, and 1500 °C for 3 h, respectively. Incomplete solid solution was observed in calcined powders at 1100, 1200 and 1300 °C, and the 1500 °C calcined powder exhibited poor flowability due to intense sintering effect. The 1400 °C calcined powders were eventually determined to be the optimized feedstock for proper phase structure (cubic phase), great flowability, suitable apparent density and particle size distribution, etc. 10YGYZ TBCs with the optimized feedstock were prepared by APS, exhibiting pure c phase and good chemical uniformity. Controllable preparation of coatings with different porosity (i.e., 7%–9% and 12%–14%) was realized by stand-off distance adjustment.

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Macroscopic particle modeling in air plasma spraying

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2018.07.056 ◽

2019 ◽

Vol 364 ◽

pp. 449-456 ◽

Cited By ~ 3

Author(s):

K. Bobzin ◽

M. Öte ◽

M.A. Knoch ◽

I. Alkhasli

Keyword(s):

Plasma Spraying ◽

Air Plasma ◽

Air Plasma Spraying ◽

Particle Modeling

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Thermal Cycling Behavior of Lanthanum-Cerium Oxide Thermal Barrier Coatings Prepared by Air Plasma Spraying

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1759 ◽

2007 ◽

Vol 336-338 ◽

pp. 1759-1761 ◽

Cited By ~ 9

Author(s):

Wen Ma ◽

Yue Ma ◽

Sheng Kai Gong ◽

Hui Bin Xu ◽

Xue Qiang Cao

Keyword(s):

Cerium Oxide ◽

Plasma Spraying ◽

Thermal Barrier Coatings ◽

Bond Coat ◽

Room Temperature ◽

Thermal Barrier ◽

Air Plasma ◽

Air Plasma Spraying ◽

Cyclic Testing ◽

Barrier Coatings

Lanthanum-cerium oxide (La2Ce2O7, LC) is considered as a new candidate material for thermal barrier coatings (TBCs) because of its low thermal conductivity and high phase stability between room temperature and 1673K. The LC coatings with different La2O3 contents were prepared by air plasma spraying (APS) and their lifetime was evaluated by thermal cyclic testing from room temperature to 1373 K. The structures of the coatings were characterized by XRD and SEM and the deviation of the composition from the powder was determined by EDS analysis. Long time annealing for the freestanding coating at 1673K reveals that the near stoichiometric LC coating is stable up to 240h, and the stability decreases with increasing the deviation from stoichiometric LC composition. During thermal cyclic testing, spallation was observed within the top coat near the bond coat. It is considered that the effect of intrinsic stress caused by the coefficient of thermal expansion (CTE) mismatch between top coat and bond coat is larger than that of thermally grown oxide (TGO) and the bond adherence of top coat with TGO.

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