| 초록 |
Rhenium is a refractory metal with its high melting point and has a unique combination of physical and chemical properties. Rhenium coatings are applied to enhance heat resistance and endurance of components and also to protect them from corrosion, which makes it an ideal material for application in various fields such as high temperature structural materials, heat exchanger, and heat protector for space shuttle and missile thrusting systems. In this study, W-25Re is successfully bonded to C-SiC substrate with Ti interlayer by spark plasma sintering process. Ti interlayer has diffused into C-SiC substrate to form carbide intermediate phases to enhance bonding strength and also the layer brazed with W-25Re metal. The mechanical properties such as bonding strength have characterized and analyzed with the microstructure of the interfaces. The electrodeposition of Re in molten salt was further studied to obtain a thicker deposit. In the ordinary electrolysis at 0.05 V vs. Zn(II)/Zn, the current density decreased from 1.2 mA cm-2 to 0.3 mA cm-2 in 6h. It was found that the soluble Re species slowly changes to insoluble ones in the melt. Electrodeposition was carried out under the same condition as above except for the intermittent addition of APR every 2h. The Voltage was kept at the initial value and the thickness was 20 μm. The intermittent addition of APR was confirmed to be effective to obtain a thicker tungsten film. The deposited Re films are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). |
