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Structure, thermal stability and chromaticity investigation of TiB2 based high temperature solar selective absorbing coatings
摘要： Transition metal titanium diboride (TiB2) is a promising material for the solar selective absorbing coatings due to its favorable spectral selectivity and thermal stability. In this research, spectrally selective TiB2/Al2O3 tandem absorber is deposited on stainless steel (SS), which exhibits a high solar absorptance (αs = 0.93) and a low thermal emissivity (ε = 0.11). In this tandem absorber, the TiB2 acts as the main absorber layer and the Al2O3 acts as an antire?ection layer. The tandem absorber coating is systematically characterized by ultra-high resolution scanning electron microscope (SEM), UV–vis-NIR spectrophotometer, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Micro-Raman techniques. The thermal stability in vacuum of the SS/TiB2/Al2O3 tandem absorber coatings is investigated in the temperature range of 400–800 °C for 2 h and 100 h, respectively. SEM and Raman spectra indicate that the change of surface morphology and chemical composition for the coating result in the degradation of optical performance. With the di?erent annealed temperature, the SS/TiB2/Al2O3 tandem absorber coatings exhibit di?erent color, which is further investigated using chromaticity diagram.
关键词： Chromaticity,Titanium boride,Structure,Thermal stability,Solar selective absorbing coatings
更新于2025-09-19 17:15:36
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Evolution of the Structure and Properties of High-Chromium Heat-Resistant VZh159 Alloy Prepared by Selective Laser Melting: Part II
摘要： The evolution of the structural-phase state of the VZh159 alloy fabricated by selective laser melting after various types of thermal exposure and hot isostatic pressing (HIP) is studied. The effect of a long 500-h exposure at temperatures of 800 and 900°C on the phase composition and morphology of structural components is determined. The short-term and long-term strength of the material in various conditions are studied. It is shown that the segregation of dispersed particles of the σ phase after the gas-static treatment followed by aging and after prolonged exposure at high temperatures does not have a significant negative effect on the plastic and strength characteristics of the alloy. The long-term strength of the synthesized metal after the 500-h exposure at a temperature of 900°C corresponds to the certified values for the deformed semifinished product of the VZh159 alloy.
关键词： boride,heat treatment,σ-phase,HIP,gas-static treatment,VZh159,selective laser melting (SLM),transmission electron microscopy,cellular structure
更新于2025-09-19 17:13:59
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Evolution of the Structure and Properties of High-Chromium Heat-Resistant VZh159 Alloy Prepared by Selective Laser Melting: Part I
摘要： The evolution of the structural-phase state of the VZh159 alloy fabricated by selective laser melting after various types of thermal exposure and hot isostatic pressing (HIP) is studied. The effect of a long 500-h exposure at temperatures of 800 and 900°C on the phase composition and morphology of structural components is determined. The short-term and long-term strength of the material in various conditions are studied. It is shown that the segregation of dispersed particles of the σ phase after the gas-static treatment followed by aging and after prolonged exposure at high temperatures does not have a significant negative effect on the plastic and strength characteristics of the alloy. The long-term strength of the synthesized metal after the 500-h exposure at a temperature of 900°C corresponds to the certified values for the deformed semifinished product of the VZh159 alloy.
关键词： σ phase,VZh159,HIP,heat treatment,boride,transmission electron microscopy,gas-static treatment,selective laser melting (SLM),cellular structure
更新于2025-09-19 17:13:59
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Damage analysis of a perfect broadband absorber by a femtosecond laser
摘要： Plasmonic metamaterial absorbers are particularly important in different applications such as photodetectors, microbolometers and solar cells. in this paper, we propose a tungsten boride (WB, a refractory ceramic) based broadband metamaterial absorber whose optical properties is numerically analyzed and experimentally characterized. We have also analyzed the damage characteristics of this absorber using a femtosecond laser and compared with an ordinary Au metamaterial absorber. We observe that WB has almost the double absorption bandwidth with absorption more than 90% over the spectral range of 950 to 1400 nm when compared with the Au counterpart. Furthermore, we show that Au metamaterial is damaged at the power of around 36.4 mW whereas WB metamaterial is not damaged at that power (WB has high tammann temperature than Au)-however the atom of WB material was knocked off by the bombardment of a femtosecond laser.
关键词： tungsten boride,femtosecond laser,broadband absorption,damage analysis,Plasmonic metamaterial absorbers
更新于2025-09-11 14:15:04