Infrared Electrochromic Devices Based on Thin Metal Films

Abstract Tunable emissivity technology is promising for the dynamic regulation of infrared radiation. Herein, infrared electrochromic devices based on thin metal films that operate via a novel hydrogen‐induced metal–insulator transition are demonstrated. The use of thin magnesium–nickel (MgxNi) alloy films as both a variable emissivity material and top conductive electrode simplifies the device structure and ensures that large changes in emissivity can be achieved. The constructed sandwich‐structured electrochromic devices also have polyethyleneimine (PEI) as a middle proton‐conducting electrolyte layer and hydrogen tungsten bronze (HxWO3)/indium tin oxide (ITO) as a bottom ion‐storage layer. Upon application of a voltage of ±2.6 V, the emissivity of the MgxNi/Pd/PEI/HxWO3/ITO device can be reversibly regulated, with emissivity changes of 0.48 and 0.43 in the 3–5 and 7.5–14 µm atmospheric windows, respectively. Under open‐circuit conditions, the high‐emissivity state of the device can be stably maintained for 3 h. The emissivity change is affected by the composition and thickness of the MgxNi film and the device failure mechanism involves the breakage and oxidation of this film after cycling. Corresponding flexible devices that exhibit electrochromism in the visible region have great potential for adaptive thermal camouflage, smart thermal management, and dynamic information displays

Corrosion Behavior of 2205 Steel in Simulated Hydrothermal Area

Deep-sea hydrothermal area has a lot of mineral resources, and study the corrosion behavior of metal in deep-sea hydrothermal area is useful for marine resource development. Electrochemical impedance spectroscopy, linear polarization, potentiodynamic polarization and Mott-Schottky analysis were used to study the electrochemical properties of 2205 steel in 20 MPa hydrostatic pressure 3.5% NaCl solution with different temperatures. Corrosion morphologies and corrosion products of 2205 steel after electrochemical tests were analyzed by SEM, EDS and white light interferometry. The results show that 2205 steel has good pitting resistance under 25 degrees C in simulated hydrothermal area, pit occurred on the surface of 2205 steel after the solution temperature reaching 65 degrees C crack-shaped pit occurred on the surface of 2205 steel under 150 and 200 degrees C Pit occurs in austenite phase at 65 degrees C and occurs in ferrite phase at 100 similar to 200 degrees C Impedance and linear polarization resistance of 2205 steel first decrease and then increase with temperature increasing in simulated hydrothermal area, and impedance and linear polarization resistance under 150 degrees C are lowest. Pitting potential of 2205 steel first negative shift and then positive shift, and carrier density of passive film formed in simulated hydrothermal area increase with temperature increasing

Transparent dynamic infrared emissivity regulators

Abstract Dynamic infrared emissivity regulators, which can efficiently modulate infrared radiation beyond vision, have emerged as an attractive technology in the energy and information fields. The realization of the independent modulation of visible and infrared spectra is a challenging and important task for the application of dynamic infrared emissivity regulators in the fields of smart thermal management and multispectral camouflage. Here, we demonstrate an electrically controlled infrared emissivity regulator that can achieve independent modulation of the infrared emissivity while maintaining a high visible transparency (84.7% at 400–760 nm). The regulators show high degree of emissivity regulation (0.51 at 3–5 μm, 0.41 at 7.5–13 μm), fast response (  104 cycles). The infrared emissivity regulation is attributed to the modification of the carrier concentration in the surface depletion layer of aluminum-doped zinc oxide nanocrystals. This transparent infrared emissivity regulator provides opportunities for applications such as on-demand smart thermal management, multispectral displays, and adaptive camouflage