| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 103 === This study adopts an efficient microwave-assisted route to deposit ZnO and Al2O3 nanoparticles onto microscaled carbon fibers as a filament for infrared heater. The microwave deposition is able to coat different densities of metal oxides on the surface of carbon fibers by adjusting ionic concentration of Zn2+ and Al3+. The highly-crystalline ZnO and Al2O3 nanoparticles can be formed under microwave irradiation of 900 W for 6 min. It has shown that both the heating rate and maximal temperature are an increasing function of the surface density of metal oxides. This improved thermal efficiency originates from the decoration of ZnO and Al2O3 onto the carbon fibers, liberating the IR-light illumination with different wavelengths. Herein the ceramic nanoparticle serves as an active site for IR illumination, thus, facilitating an enhancing thermal efficiency. To maximize the thermal efficiency, an microwave-assisted treatment is employed to create more oxide groups (e.g., carbonyl and carboxylic groups) that provide more linking sites for decorating ZnO and Al2O3 nanoparticles over the carbon fibers. It can be found that the microwave-assisted method effectively favors the weight loading of metal oxides. The IR heaters fabricated with ZnO and Al2O3 nanoparticles display the maximal temperatures of 184 and 213°C, respectively. As compared the blank carbon fiber heater, an increase of 68 and 77% in the equilibrium temperature for both IR heaters. The improved heating rates of heaters are also strongly enhanced for both IR heaters. This satisfied result expressed that a robust design that combined with carbon heaters and decoration of nanoparticles shows a potential feasibility for commercializing IR-related IR heaters with high thermal performance.
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