| Summary: | 碩士 === 崑山科技大學 === 電子工程研究所 === 98 === Ce-doped BiNbO4 ceramics and Sb-doped ones with CuO addition were prepared by using a reaction-sintering process. X-ray diffraction patterns showed that the ceramics are mainly composed of orthorhombic BiNbO4 structures and a second phase of triclinic BiNbO4 structure is found. With the addition of CuO sintering aids, the sintering temperature can be lowered down 100~ 200℃ while keeping a similar apparent density. However, the triclinic BiNbO4 phase of the samples became more prominent as the CuO content or the sintering temperature increased. Bi0.97Ce0.03NbO4 ceramics, sintered at 950℃ for 6h with 2wt% CuO sintering aids, exhibited a maximum density of 6.79 g/cm3, and their microwave dielectric properties were as following: εr=38, Qxf=1691 GHz, and τf=-4.1 ppm/℃. BiNb0.95Sb0.05O4 ceramics sintered at 1000℃ for 4 h showed an apparent density of 7.03 g/cm3, and the one sintered at 910℃ for 6 h exhibited the following microwave dielectric properties: εr= 41, Qxf = 933 GHz, τf= -8.2 ppm/℃.
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