Study On The Component,Structure And Properties Of Low Temperature Sintered CaO-B₂O₃-SiO₂ Ceramics

The development of electronic information technology has increased the demand for substrate materials with excellent performance and low sintering temperature,and also attracted the attention of low temperature co-fired ceramics(LTCC).CaO-B2O3-SiO2(CBS),which has the advantages of low sintering temperature,low dielectric constant,low dielectric loss and thermal expansion coefficient closed to silicon phase,is an ideal substrate material and has become a research hotspot.In this paper,CBS mixed-powder was prepared by solid state reaction method and CBS ceramics were prepared by atmospheric pressure sintering.The composition range of CBS was determined through literature review and phase diagram analysis firstly.And then four series of sixteen recipes were designed,and the samples were sintered at 900?1000?.Next by the means of DSC,XRD,SEM?FTIR and broadband dielectric spectroscopy,the effects of B2O3 contents and mass ratio of Ca/Si and ZnO and ZrO2 on the structure and properties of CBS were studied.Finally,the optimal formula of CBS under the corresponding conditions was obtained.The results show that B2O3,a low melting point oxide,can reduce the temperature of liquid phase in CBS ceramics and promote the sintering of CBS ceramics.CaO and SiO2 are the main components of the formation of wollastonite.The appropriate mass ratio of Ca/Si can increase the content of wollastonite and improve the performance of CBS ceramics.ZnO can form low melting point glass phase with B2O3 and SiO2 to reduce the sintering temperature of CBS ceramics.As a nucleating agent,ZrO2 can produce CaZrO3 and induce the formation of wollastonite.So by adjusting the contents of B2O3,the mass ratio of Ca/Si,the contents of additives ZnO and ZrO2,the CBS with low sintering temperature and good dielectric properties can be obtained.The sample with 10wt%B2O3 and with mass ratio of Ca/Si of 1 sintered at 975? shows good performances of p=2.6784 g·cm-3,sr=5.97,tan?=2.2×10-3(1 MHz).On the basis of the above composition,the sample with lwt%ZnO sintered at 950? shows excellent performance of p=2.7349 g·cm-3,?r=5.20,tan?=3.1×10-3(1 MHz);the sample with 1.5wt%ZrO2 sintered at 950? shows excellent performance of p=2.7760 g·cm-3,sr=5.62,tan?=1.8×10-3(1 MHz).