Thick tungsten coating on ferritic–martensitic steel applied with a vacuum plasma spray coating method

Moon, Se Youn; Choi, Chea Hong; Kim, Hoseok; Oh, Philyoung; Hong, Bong Guen; Kim, Suk Kwon; Lee, Jun Young

doi:10.1016/j.surfcoat.2015.09.008

Cited by 22 publications

(5 citation statements)

References 17 publications

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“…Obviously, this residual stress level is very high and with that the stored elastic energy which can promote delamination of the rather thick tungsten coatings. As pointed out earlier, the used approach of graduation of the interface can significantly reduce localized deformation and hence degradation of near-interface regions and by that reduce the risk of failure of the coatings [18].…”

Section: Residual Stress Evaluationmentioning

confidence: 93%

“…Recently, it was demonstrated that the deposition of a 3 mm thick tungsten layer on a 50*50 mm² ferritic martensitic steel substrate is possible without spallation by careful control of the heating and cooling procedures. Also the hardness of the coatings was only about 10% less than the bulk value indicating a low porosity of the coating [18]. However, the problem of stresses induced by the large difference in thermal expansion coefficients between coating and substrate remain.…”

Section: Introductionmentioning

confidence: 93%

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Vacuum plasma spraying of functionally graded tungsten/EUROFER97 coatings for fusion applications

Vaßen

Rauwald

Guillon

et al. 2018

Fusion Engineering and Design

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As structural materials for future fusion power plants, reduced activation ferritic martensitic steels as EUROFER97 can be used. Unfortunately, the interaction of the plasma with the steel would result in a limited lifetime, so protective layers are investigated. An excellent protective material is tungsten, as it shows unique properties with respect to low sputtering, high melting points and low activation. However, the mismatch of thermo-physical properties between tungsten and EUROFER97 can lead to large stress levels and even failure. A possible way to overcome this problem is the use of functionally graded material (FGM). The paper will describe the manufacture of these FGMs by vacuum plasma spraying and their characterization. First of all, two different feeding lines have been used to produce the coatings. A major problem lies in different melting points of tungsten and steel. So the particle size distribution has to be adjusted to achieve sufficient melting of both materials during the spray process. In a second step, the feeding rates were optimized to obtain the wanted amount of tungsten and steel phases in the graded structures. In a thermal spray process, the gradient cannot be made continuously, however it has to be applied in a step-wise manner. In this investigation, samples with 3 and 5 different concentrations (excluding the pure steel and tungsten part) have been produced. The microstructures of these layers have been investigated. In addition, hardness was measured and the residual stress state was determined by the hole drilling method.

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Section: Residual Stress Evaluationmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 93%

Vacuum plasma spraying of functionally graded tungsten/EUROFER97 coatings for fusion applications

Vaßen

Rauwald

Guillon

et al. 2018

Fusion Engineering and Design

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“…Igitkhanov et al [91] provided some boundary conditions for the plasma-facing components (PFCs) in future fusion devices (such as DEMO), suggesting that the thickness of the W armor material of the PFCs can be only ~ 3 mm. Therefore, it is reasonable to produce W coatings to meet the application requirements in PFCs [92][93][94][95][96][97] by coating manufacturing technologies, such as chemical vapor deposition (CVD), vacuum plasma spray (VPS) and atmospheric plasma spray (APS). Notably, the W coatings could join directly with the heat sink materials or structural materials.…”

Section: Coating and Additive Manufacturing Techniquesmentioning

confidence: 99%

“…But the deposition rate of the CVD-W is ~ 0.6 mm h −1 , which may limit the W material production. Moon et al [94] successfully produced a W coating with ~ 3.7 mm thickness on the ferritic-martensitic steel.…”

Section: Coating and Additive Manufacturing Techniquesmentioning

confidence: 99%

Manufacturing of tungsten and tungsten composites for fusion application via different routes

2019

Tungsten

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Tungsten is a refractory metal with the highest melting point of all metals, which is considered as a promising candidate material for plasma-facing materials in the future fusion reactor. However, tungsten faces several challenges from intrinsic embrittlement, irradiation embrittlement and recrystallization embrittlement during the operation of the fusion reactor. To satisfy the fusion engineering application, an advanced tungsten material with the fine grain and dense microstructure is required and developed. This paper briefly introduces the application background of the tungsten materials and mainly illustrates a series of common techniques for manufacturing advance tungsten materials, such as powder preparation technologies, bulk densification techniques, continuous processing technologies and the coating and additive manufacturing technologies. Furthermore, the development prospects for manufacturing techniques of tungsten materials are also presented in the end. Considering the tungsten materials employed in the fusion engineering application, combining these scalable techniques of the wet-chemical method, pressureless sintering and continuous deformation processing techniques would be the possible research and development routes to realize the manufacture of the advanced tungsten materials.

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“…Figure 3 shows the plasma spray coating process of single-layer HfC and TiC coatings and multilayer HfC/TiC coatings. The process included pre-heating, coating, and post-heating steps, where pre-heating and post-heating were performed to prevent cracking and delamination of the coating layer caused by differences in the thermal expansion coefficients between the substrate and coating layer [14]. For the multilayer HfC/TiC samples, the layers were coated sequentially in the vacuum chamber.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Vacuum Plasma Sprayed HfC, TiC, and HfC/TiC Ultra-High-Temperature Ceramic Coatings

2019

Self Cite

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To improve the oxidation resistance of carbon composites at high temperatures, hafnium carbide (HfC) and titanium carbide (TiC) ultra-high-temperature ceramic coatings were deposited using vacuum plasma spraying. Single-layer HfC and TiC coatings and multilayer HfC/TiC coatings were fabricated and compared. The microstructure and composition of the fabricated coatings were analyzed using field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The coating thicknesses of the HfC and TiC single-layer coatings were 165 µm and 140 µm, respectively, while the thicknesses of the HfC and TiC layers in the HfC/TiC multi-layer coating were 40 µm and 50 µm, respectively. No oxides were observed in any of the coating layers. The porosity was analyzed from cross-sectional images of the coating layers obtained using optical microscopy. Five random areas for each coating layer specimen were analyzed, and average porosity values of approximately 16.8% for the HfC coating and 22.5% for the TiC coating were determined. Furthermore, the mechanical properties of the coating layers were investigated by measuring the hardness of the cross section and surface roughness. The hardness values of the HfC and TiC coatings were 1650.7 HV and 753.6 HV, respectively. The hardness values of the HfC and TiC layers in the multilayer sample were 1563.5 HV and 1059.2 HV, respectively. The roughness values were 5.71 µm for the HfC coating, 4.30 µm for the TiC coating, and 3.32 µm for the HfC/TiC coating.

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Thick tungsten coating on ferritic–martensitic steel applied with a vacuum plasma spray coating method

Cited by 22 publications

References 17 publications

Vacuum plasma spraying of functionally graded tungsten/EUROFER97 coatings for fusion applications

Vacuum plasma spraying of functionally graded tungsten/EUROFER97 coatings for fusion applications

Manufacturing of tungsten and tungsten composites for fusion application via different routes

Microstructure and Mechanical Properties of Vacuum Plasma Sprayed HfC, TiC, and HfC/TiC Ultra-High-Temperature Ceramic Coatings

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