Optical properties of nanostructured tungsten in near infrared range

Kajita, Shin; Ohno, Noriyasu; Yokochi, Takanori; Yoshida, N.; Yoshihara, Reiko; Takamura, S.; Hatae, T.

doi:10.1088/0741-3335/54/10/105015

Cited by 11 publications

(6 citation statements)

References 26 publications

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“…To estimate the temperature from the IR intensity, a calibration is necessary by considering the transmission, sensitivity of the detector and the emissivity of the sample. Most crucially, the emissivity varies significantly as a function of temperature and due to the surface morphology changes [16]. For the pristine sample, the temperature dependence of the emissivity in the observed wavelength range was taken into account, while an emissivity of 0.8 was assumed for the nanostructured W according to the measurement.…”

Section: Methodsmentioning

confidence: 99%

Thermal response of nanostructured tungsten

Kajita¹,

Temmerman²,

Morgan³

et al. 2014

Nucl. Fusion

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The thermal response of nanostructured tungsten, which was fabricated in the linear divertor simulator NAGDIS-II, was investigated using pulsed plasma in the MAGNUM-PSI device and by using high powered laser pulses. The temperature evolution in response to the pulses was measured with an infrared fast framing camera. The temperature increase in response to the pulses on the nanostructured sample was significantly greater than that of the pristine sample both for plasma and laser pulses. After the pulsed plasma/laser irradiation, the nanostructured surface was observed to have melted although the measured surface temperature was much less than the melting temperature. The mechanism to account for the difference in the temporal evolution of temperature between the nanostructured and pristine samples is discussed. It is suggested that there are thermally isolated part on the nanostructures and anomalous temperature increase and melting have occurred locally on them. The amount of vapourized tungsten in response to type-I edge localized mode in ITER is discussed based on experimental observation.

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Section: Methodsmentioning

confidence: 99%

Thermal response of nanostructured tungsten

Kajita¹,

Temmerman²,

Morgan³

et al. 2014

Nucl. Fusion

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“…The fiber density of the "fuzz" layer depends on the plasma load: a dense "fuzz"-type structure, Figure 6a,b, and a rare fuzz-type structure Figure 6c,d is observed. The "fuzz" layer thickness is up to 1.5 microns, and the diameter of fibers is from ~20 nm to ~50 nm (Figures 5-7) typically observed in experiments, see [57][58][59][60][61][62][63][64][65][66][67][68][69][70].…”

Section: High-porous Micro-structured Surfacementioning

confidence: 73%

“…Secondary electron emission decreases by about 50%. Such materials absorb almost all photons in the spectrum from ultraviolet to near infrared (>99%) [65], and the optical emissivity is increased [66,67].…”

Section: Advantages Of Practical Applicationsmentioning

confidence: 99%

Heat Transfer on Micro and Nanostructured Rough Surfaces Synthesized by Plasma

Дедов

Budaev

2022

Symmetry

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The review summarizes recent experimental results of studying heat transfer on rough surfaces synthesized by plasma. The plasma-surface interaction leads to the stochastic clustering of the surface roughness with a high specific area breaking the symmetry of the virgin surface of the initial crystalline materials. Such a surface is qualitatively different from the ordinary Brownian surface. The micro- and nanostructured surface consist of pores, craters, and nanofibers of size from tens of nanometers to tens of microns, which can provide new heat transfer properties related to a violation of the symmetry of the initial materials. In recent years, new results have been obtained in the study of heat transfer during phase change on plasma-modified surfaces in relation to energy, chemical, and cryogenic technologies. The objective of the review is to describe the specific structure of refractory metals after high-temperature plasma irradiation and the potential application of plasma processing of materials in order to create heat exchange surfaces that provide a significant intensification of two-phase heat transfer. Refractory metals with such a highly porous rough surface can be used as plasma-facing components for operation under extreme heat and plasma loads in thermonuclear and nuclear reactors, as catalysts for hydrogen production, as well as in biotechnology and biomedical applications.

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“…While these structures are potentially fatal to the fusion plasma when grown [ 3 ], they do exhibit characteristics that could be exploited in other applications. A high porosity, a low density of about 10% of the bulk material, large surface area, increased emissivity, and decreased reflectance are all properties of the nanostructured surface [ 4 , 5 , 6 , 7 ]. The nanostructures are produced by prolonged exposure to a flux of helium ions while the tungsten is at an elevated temperature.…”

Section: Introductionmentioning

confidence: 99%

Nanostructuring of Palladium with Low-Temperature Helium Plasma

et al. 2015

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Impingement of high fluxes of helium ions upon metals at elevated temperatures has given rise to the growth of nanostructured layers on the surface of several metals, such as tungsten and molybdenum. These nanostructured layers grow from the bulk material and have greatly increased surface area over that of a not nanostructured surface. They are also superior to deposited nanostructures due to a lack of worries over adhesion and differences in material properties. Several palladium samples of varying thickness were biased and exposed to a helium helicon plasma. The nanostructures were characterized as a function of the thickness of the palladium layer and of temperature. Bubbles of ~100 nm in diameter appear to be integral to the nanostructuring process. Nanostructured palladium is also shown to have better catalytic activity than not nanostructured palladium.

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Optical properties of nanostructured tungsten in near infrared range

Cited by 11 publications

References 26 publications

Thermal response of nanostructured tungsten

Thermal response of nanostructured tungsten

Heat Transfer on Micro and Nanostructured Rough Surfaces Synthesized by Plasma

Nanostructuring of Palladium with Low-Temperature Helium Plasma

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