Research On Ca-Mg-Si Based Glass+Al₂O₃ Ceramic Materials

The essential requirements of LTCC materials applied to high frequencies are low dielectric constant（ε_r）,high quality factor（Q×f）,and the temperature coefficient of resonance frequency（τ_?）is required to be as close to zero as possible.In addition,due to the development of miniaturization and thinning of electronic components,LTCC substrate will be affected by the assembly and drop impact in the process of production,fabrication and application,so it is crucial to ensure the mechanical reliability of the device.Superior mechanical properties can prevent the fracture of the LTCC substrate in the process of wiring and typesetting.Glass/ceramic composites are commonly used as candidate materials for LTCC materials owing to their unique advantages,such as tunable glass content,good dielectric performance,and high mechanical performance.In the study of this thesis,Ca-Mg-Si based glass was selected as the base glass and Al₂O₃as the ceramic filler,and the effects of glass doping,ceramic particle size,glass/ceramic ratio and sintering temperature on the sintering behavior of the composite materials,micromorphology,crystal phase structure,mechanical properties,and dielectric properties were studied in depth.（1）Research on CaO-MgO-SiO₂-Al₂O₃（CMSA）glass/Al₂O₃ceramic composites.Al₂O₃of 3wt.%,5wt.%,7wt.%and 9wt.%were added to Ca-Mg-Si based glass,respectively.Studies show that CMSA glass/Al₂O₃ceramics doped with 7wt.%Al₂O₃exhibit the best mechanical properties.When the Al₂O₃ceramic content is 40wt.%and the sintering temperature is 910℃,the composites show the maximum flexural strength of 264MPa,the dielectric constant is 7.88,Q×?is 7615（12GHz）,andτ_?is-27ppm/℃.（2）Research on CaO-MgO-SiO₂-Al₂O₃-Y₂O₃（CMSAY）glass/Al₂O₃ceramic composites.The rare earth oxide Y₂O₃of 0.5wt.%,1wt.%,2wt.%and 3wt.%were doped in CMSA glass,respectively.Studies show that CMSAY glass/Al₂O₃ceramics doped with 1wt.%Y₂O₃exhibit the best mechanical properties.When the Al₂O₃ceramic content is 35wt.%and the sintering temperature is 910℃,the composites show the maximum flexural strength of 286MPa,the dielectric constant is 7.78,Q×?is 9035（12GHz）andτ_?is-33ppm/℃.（3）Research on CaO-MgO-SiO₂-Al₂O₃-Ca F₂（CMSAC）glass/Al₂O₃ceramic composites.The nucleator Ca F₂of 0.5wt.%,1wt.%,2wt.%and 3wt.%were doped in CMSA glass,respectively.Studies show that CMSAC glass/Al₂O₃ceramics doped with1wt.%Ca F₂exhibit the best mechanical properties.When the Al₂O₃ceramic content is35wt.%and the sintering temperature is 910℃,the composites show the maximum flexural strength of 310MPa,the dielectric constant is 7.75,Q×?is 10585（12GHz）andτ_?is-30ppm/℃.（4）Research on the effect of Al₂O₃ceramic particle size on the properties of glass/ceramic composites.In the CMSAC glass/Al₂O₃ceramics system,Al₂O₃ceramics with particle size of 1.12μm,1.83μm,2.14μm and 5.64μm were selected to study the effect of the change of ceramic particle size on the properties of glass/ceramic composites.Studies show that the Al₂O₃ceramic with a particle size of 1.83μm combined with CMSAC glass obtain the maximum flexural strength of 310MPa.