Journal of Functional Materials and Devices, PRChina bookmark2 Effects of Microwave Dielectric Properties Yang Qiuhong, EungSoo Kim2, Xu Jun3, Yan Zhongyan1 (1. School of Materials Science and Engineering, Shanghai University, Shanghai 201800, China; 2. Department of Ceramic Engineering, Korea University of Science and Technology; 3. Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, Shanghai--The PbO-B2O3-based glass additive can reduce the sintering temperature of PCLFN ceramics from 100 to 150oC. When PCLFN is sintered in air at 1050oC, low-melting compounds such as B23, V25, and Bi23 are commonly used for sintering. Additive 13-62, in lead-based ceramics, P (0 is also a commonly used sintering aid due to its lower melting point, and due to P (0 volatilization problems during the sintering process, an appropriate excess of P (0 helps Sintering of lead-based ceramics 17. It has been found that composite doping reduces the sintering temperature and maintains good dielectric properties more effectively than single additives, such as BiN (CuO+V25 for system 3 as additive 18 and Ba3 system for B2O3). +S (25 for additive 14. + can improve the microwave dielectric properties, in which the composition is (Fe.5NW5 + 3 (PCLFN) ceramic sintering at 1150 ~ 1250C temperature for 3h has good microwave performance. This experiment Various low Point P (0 Effects compound, B2O3, and P (0-B2O3 based glass on PCLFN microwave dielectric properties, and from the viewpoint of forming the glass component of glass investigate the relationship between the electrical properties of microwave dielectric.
2 The purity of the experimental process is more than 99.9%. According to the designed chemical composition ratio, distilled water is added, and the slurry is dried in an oven with Zi02 ball for 24 hours, and then synthesized at 900C for 4 hours. The PCLFN sample adopts the traditional solid phase reaction. Two-step sound system. The synthesized powder is mixed with a variety of low-melting-point compounds or glass additives, added with distilled water, and then ball-milled for 24 hours. After drying, the powder is made into a sound at 145MP isostatic pressure! 10mm, tall cylinder, then sintered in 950~1100C air for 3h. Density was determined by Archimedes drainage method. Sintered samples were observed by X-ray diffraction (XRD decantation phase composition, using scanning electrons) to observe the microstructure of the sample. The Qf of the product of the dielectric constant K and the quality factor and frequency was measured using Hakki-Coleman's TE0 mode at 5F6GHz frequency. Determination. The frequency temperature coefficient TCF is measured at 25 ~ 805C using the cavity method.
3 Results and discussion Firstly, P was selected as sintering aid (0). It was found that P (0) could not reduce the sintering temperature of PCLFN ceramics nor improve its dielectric properties. When P (0 addition amount x1. at 11005C temperature air In the sintering, Qf4715F4975GHz, the dielectric constant K is only 72, the ytterbium is not sintered; the phase composition of the sintered sample in the air sintered at 1150C under Qf 1025C, all samples have two crystal phases: perovskite phase and pyrochlore phase, not Found that the third phase exists.
The XRD patterns of PCLFN samples doped with P (0-B203 glass additive) and PCLFN samples with other additives have similar XRD patterns. The content of pyrochlore phase relative to perovskite phase is calculated by the formula: !per(110)' (222) is the diffraction intensity f per pero (110) of the pyrochlore host 222, which is the main peak of the perovskite phase, and the Vb 0% component is likely not to enter the host lattice, but acts as a liquid phase assist agent. The influence of Qf value is relatively small.When n2.09tP, samples doped with P>0-Bb0c-B"20c glass can be doped with P>0-Bb0c-B"20c and P>0-Bb0c-V205 respectively at 6. The relationship between the bulk density and the sintering temperature of PCLFN samples of glass additives shows that the relationship between the density and the sintering temperature has the same tendency as the change of the dielectric constant K and the sintering temperature.The dielectric constant increases with the sintering temperature. The increase is due to the increase in the sintered density.For samples doped with 0.5 wt% P>0-Bb0c-Bi20c, the bulk density is very low and the microwave dielectric properties are poor, because the glass phase is too small to wet out. Ceramic ceramic pottery I ceramics are not completely sintered, have a low dielectric constant, and have a low bulk density, so there is no Low sintering temperature: As the content of glass phase increases, the sintering temperature is reduced to 1025oC, so the amount of P>0-Bb0c-B"20c cannot be low-Bb0c-Vb05 glass samples, when the doping amount is 0.5wt%, The sintering temperature can be reduced to 1050oC; when the doping amount is 2.09tP, the sintering temperature can be further reduced to 1000C. At the same time, the Qf value decreases with the increase of doping amount.
Although the content of the second phase pyrochlore phase changes little and no third phase appears, the increase of the glass phase will still affect the dielectric properties of PCLFN.
With the further increase of the glass phase content of -Bb0c-Vb05, the sintering temperature of PCLFN may be further reduced, but at the same time, it is at the expense of the decrease of Qf value.
P>0, Bb0c are all low-melting compounds, and the melting point of PCLFN samples whose temperature is respectively mixed with different glass additives is related to the sintering temperature. The above experimental results show that P0-B203-based glass is more than single-component P0 or B23 can more effectively reduce the sintering temperature of PCLFN ceramics.
From the perspective of glass formation, multiple components can form glass that is more stable and has a lower melting point, whereas pure monocomponent compounds generally have higher 9is energies from the point of view of the energy minimization principle. At high temperatures, these pure components can easily form complexes or complex compounds with other compounds. In particular, simple compounds such as the glass formers B(0) and Si2, which have strong field strengths, are easier to form with other compounds. Complex compounds or melts. If such a single-component compound is used as a sintering aid alone, it will chemically react with the stoichiometric ceramic composition such that the ceramic main crystal phase deviates from its chemical composition and forms a second or eutectic phase. This will usually lead to insignificant cooling effects and deteriorate the dielectric properties of the ceramic. Only when the new compound formed is another low-melting compound and the sintering temperature can be lowered, the cooling effect can be achieved = 5. Therefore, the single component P0 can not reduce the sintering temperature of PCLFN, and can not improve the microwave dielectric properties at the same time. performance. The addition of B (0) can only reduce the sintering temperature of 50C. At the same time, as the content of the second phase increases with the amount of B (0), the microwave dielectric properties also decrease. However, the PCLFN ceramics doped with multi-component P0-B(0)-based glasses have very little change in the content of the second phase with the amount of glass, and can be sintered at a lower temperature and maintain good microwave dielectric properties. The two-component P0-B(0) glass can reduce the sintering temperature of 100oC, and the three components P0 can be sintered at a low temperature of 150C. It can also be seen that the different chemical compositions in the glass will affect the microwave dielectric properties of PCLFN ceramics. Among the three P0-B(0)-based glasses, P0-B(0)-V (05 glass is the best sintering aid.
P0-B (03-based multi-component glass additive can effectively reduce the sintering temperature of PCLFN ceramics and maintain good microwave dielectric properties compared to single-component compounds, because multiple components have lower Gis energy and can form The more stable and lower melting glass, the single component P0 can not reduce the sintering temperature of PCLFN, B(0) can only reduce 50oC, and the two component P0-B(0) glass can reduce 100oC, while the three components P0-B (0)-Bi(0) and P0-B(0)-V(0>glasses can reduce 150C. Different compositions in glass can also affect the dielectric properties of PCLFN ceramics. Three P0-B(0) groups In multi-component glass, P0-B(0)-V (05 glass is the most
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