Synthesis Of Silicon Carbide Containing Beryllium And The Research Of Electromagnetic Performance

Abstract:Silicon carbide(SiC) ceramics which were prepared by polymer mixing with heterogeneous elements, have become a hot spot recently. Concerning with the low dielectric constant, low dielectric loss and special photochemical properties of beryllium materials, beryllium element has been chosen. In this paper the electromagnetic performance of beryllium containing silicon carbide(Be-SiC) ceramics which were prepared by beryllium polymer precursor(PBeCS) was studied. After comparing the principle and application scope of several material electromagnetic testing methods, the coaxial transmission/reflection method was chosen to test the materials’electromagnetic parameters.Beryllium containing polymer precursor (PBeCS) was synthesized by acetylacetone beryllium (Be(acac)2) and polycarbosilane ((PCS), and its structure and composition was researched by the analysis methods such as GPC, IR, XPS. Different PBeCS have been. Comparing the electromagnetic performance of Be-SiC ceramics prepared by the different PBeCS which were synthesized under different process conditions, it can be proved that the dopant of beryllium or its doping amount has play an role on the dielectric properties adjustment of SiC ceramics. The results show that the dopant of beryllium increases the dielectric constant and decreases the dielectric loss tan delta. And the absorption peak of dielectric loss tan delta can be shifted by changing the doping amount of beryllium. The synthesis mechanism of Be-SiC ceramic precursor, of which chemical formula was concluded to be SiC2O0.333Be0.007H3.798, has been explored.The ceramic procession of PBeCS was studied using the analysis methods such as infrared-thermo gravimetric coupling technique, XRD and so on. By comparing the electromagnetic performance of Be-SiC ceramics prepared with different ceramic procession parameters, the electromagnetic parameters variations of Be-SiC ceramics in the ceramic procession were studied. The result shows that the transition temperature has influence on the dielectric constant and dielectric loss tan delta. It is also concluded that the dielectric constant and dielectric loss tan delta increased as the density of ceramics increasing. The electromagnetic parameters changing mechanism of Be-SiC ceramics has been discussed, which laid a solid foundation for the application of Be-SiC ceramics in microwave field.