Study On Low-K Dielectric Properties Of K₂O-Al₂O₃-SiO₂ System Ceramic

B₂O₃,ZnO,MgO,CaO,Li₂O and MoO₃ were used as additives in K₂O-Al₂O₃-SiO₂ ceramics to modify properties.Effect of oxides doped on sintering temperature?microstructures and microwave dielectric properties of K2O-Al2O3-SiO2 ceramics and discussion of scientific basis for further use in LTCC technology were studied in this paper.The main results are listed below:1.The system of KAS without doping sintered at high temperature.With the increase of sintering temperature,microcrystalline phase showed a trend of decrease,glassy state showed a trend of increase.When sintered at 1370?,the KAS ceramic had the lowest dielectric constant,the value of?_r was 5.311 and the value of tan?was 5.1×10^-3 at the frequency of 1MHz.2.B₂O₃ was used as additives in KAS ceramics,B₂O₃ can low the sintering temperature of KAS ceramics to 1150?.With the increase of B₂O₃,Sintered density,dielectric constant and dielectric loss showed a trend of decrease.B₂O₃ contributes to crystallizing Quartz SiO₂ in system of KAS,and with the increase of doping amount of B₂O₃,microcrystalline phase was in increase.The properties of KAS ceramics doped 5?wt?%B₂O₃ was better,the minimal dielectric constant was 5.45655?1 MHZ?,the dielectric loss was 0.00786?1 MHZ?.3.Choose 5?wt?%of B2O3 respectively to dope with ZnO,MgO and CaO in KAS.When sintered at 1180?.With the increase of ZnO,the dielectric constant of KAS doped with B₂O₃and ZnO increased firstly,then decreased.The dielectric loss showed the same trend with the increase of ZnO.The sample of BZ1?5?wt?%B₂O₃ and 1?wt?%ZnO as additives?ceramics had the lowest dielectric constant,the value of?_r was 5.41943.The sample of BZ3?5?wt?%B₂O₃ and 3?wt?%ZnO as additives?ceramics had the lowest dielectric loss,the value of tan?was 5.8×10^-3.The sintered density of KAS doped with 5?wt?%B₂O₃ fixed and MgO increased With the increase of sintering temperature,B2O3 and MgO can effectively reduce the sintering temperature of KAS ceramics.The dielectric properties of BM3?5?wt?%B2O3 and 3?wt?%MgO as additives?was better when sintered at 1220?,the dielectric constant was 5.181?1 MHZ?,the dielectric loss was 0.0056?1 MHZ?.The minimum dielectric constant of BC3?5?wt?%B₂O₃ and 3?wt?%CaO as additives?was 5.498?tan?is 0.0074?,the maximum dielectric constant of BC4?5?wt?%B₂O₃ and 4?wt?%CaO as additives?was 5.808?tan?is0.00474?.4.Choose Li2O as additives to add to the system of KAS.When the amount of Li2O is 1%and 2%,the compact sintering temperature of KAS is 1120?,the dielectric constant are6.446 and 6.687.While the amount of Li₂O is 3%and 4%,the compact sintering temperature of KAS is 1200?,the dielectric constant are 6.458 and 6.465.A little amount of Li₂O can reduce the sintering temperature of KAS more effectively and have bigger saturated density.5.Choose MoO₃ as additives to add to the system of KAS.As the field strength of Mo⁶⁺is big,precipitine more phase of Quartz SiO₂ in system of KAS with the increase of MoO₃.A little amount of Li₂O can low the sintering temperature more effectively?can increase transverse shrinkage and increase saturated density.The dielectric constant of KAS decrease with the increase amount of MoO₃,the sample of M4?4?wt?%MoO₃ as additives?has the lowest dielectric constant,the value of?r is 5.19379.