Iridium thin films have been deposited on Si3N4（100 nm）/Si（100） substrates by magnetron sputtering. And then iridium film micro-patterns were fabricated by ion milling technique. The atomic force microscopy （AFM） measurements reveal that there is a very fiat and smooth surface with an average roughness of 0.64 nm for the iridium films. The X-ray diffraction also reveals that the deposited iridium films have a polycrystalline microstructure with （111） plane preferential orientation. The electrical resistivity of the iridium films was also measured and discussed.
Using the microwave sintering technology, the effects of phosphorus （P） additions on the microstructure and properties of the ultrafine WC-10Co alloys were investigated. The experimental results show that with only 0.3wt% P additions, full density WC-10Co cermets were obtained at temperature of 1250℃, which is 70 ℃ lower than that of the undoped counterparts. Lower sintering temperature can result in finer WC grain growth; therefore, the P-doped WC-10Co alloys exhibited higher hardness than the undoped ones. But at the same time, P doping could lead to sacrifice of fracture toughness ofWC-10Co cemented carbides.
ZnO hexagonal prism crystals were synthesized from ZnO powders by microwave heating in a short time （within 20 min） without any metal catalyst or transport agent. Zinc oxide raw materials were made by evaporating from the high-temperature zone in an enclosure atmosphere and crystals were grown on the self-source substrate. The inherent asymmetry in microwave heating provides the temperature gradient for crystal growth. Substrate and temperature distribution in the oven show significant effects on the growth of the ZnO crystal. The morphologies demonstrate that these samples are pure hexagonal prism crystals with maximum 80 lain in diameter and 600 lure in length, which possess a well faceted end and side surface. X-ray diffraction （XRD） reveals that these samples are pure crystals. The photoluminescence （PL） exhibits strong ultraviolet emission at room temperature, indicating potential applications for short-wave light-emitting photonic devices.
Zinc oxide hexagonal tubular crystals were synthesized by direct microwave heating from ZnO powders within 5 min without any metal catalysts or transport agents. ZnO source materials were evaporated from the high-temperature zone in an enclosure, and crystals were grown on the self-source substrate in an appropriate condition. The ZnO vapor formed in the high-temperature zone can deposit and grow on the powders located in the low-temperature zone to form crystals. The scanning electron microscopy （SEM） reveals that these products are hexagonal tube crystals with 80 ~rn in diameter and 250 μm in length, having a well faceted end and side surface. A possible growth mechanism and the influence of reaction temperature on the formation of crystalline ZnO hexagonal tubes were presented. The photoluminescence （PL） exhibits strong ultraviolet emission at room temperature, indicating the potential applications in short-wave light-emitting photonic devices.
ZnO sub-millimeter crystals were synthesized by microwave heating from ZnO powders without any catalyst or transport agent. Zinc oxide raw materials were evaporated from the high-temperature zone in an enclosure and crystals were grown on the self-source substrate. The thermodynamics analysis method was used to estimate the partial pressure of gases in the chamber, which shows that the pressure of ZnO could be neglected entirely in the range of experiment temperature. The kinetics analysis was employed to estimate the growth rate in different conditions, which shows a remarkable temperature gradient and a high system temperature would enhance the growth rate. Optics photos reveal that these products are hexagon crystals with 0.2-0.3 mm in diameter and 0.5-1 mm in length. A vapor-solid mechanism is proposed to explain the growth process of ZnO crystals. The temperature distribution in microwave oven is mainly determined by properties of electric field and it is different from that of a conventional method.
