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A novel kind of microwave absorption composite in Ku-band with low cost, low density and strong absorption was prepared through Bio-template carbonization and solvothermal method. The phase structures and morphologies of the composite had been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microwave absorption properties of carbonized kapok fibers and Fe3O4/kapok fibers were measured by vector network analysis (VNA). When the sample thickness is 1.5 mm, the Fe3O4/kapok fibers have an optimal absorption peak value of about -24.1 dB at 17.4 GHz and its effective absorption bandwidth lower than -10 dB reaches 2.4 GHz (from 15.6 to 18.0 GHz). The reflection loss results indicate that the Fe3O4/kapok fibers possess higher microwave absorption in the Ku-band. A possible mechanism of the improved microwave absorption performance of the composite was discussed. [ABSTRACT FROM AUTHOR]

Nanocrystalline diamond (NCD) coatings were prepared on Si3N4substrate by hot filament chemical vapor deposition (HFCVD) method with Ar/H2/CH4gas mixture. The nano hardness and elastic modulus of the NCD coatings were evaluated using a nano indenter. The results show that the diamond grains appear to be rounded with the average grain size of less than 100 nm. The average nano hardness is ∼53.5 GPa, the elastic modulus is ∼606.8 GPa, and the elastic recovery is as high as ∼80%, for the fine NCD coatings deposited with the substrate temperature of 700°C. The nano hardness and elastic modulus of the NCD coatings will increase with the substrate temperature increasing from 600°C to 700°C. [ABSTRACT FROM AUTHOR]