摘要
针对Ca-B-Si-O玻璃与Ca_(x)Mg_(1−x)TiO_(3)化合物的制备工艺进行了系统研究,并通过低温烧结制备了中介电常数Ca-B-Si-O玻璃/Ca_(x)Mg_(1−x)TiO_(3)系LTCC材料,重点研究了Ca-B-Si-O玻璃/Ca_(x)Mg_(1−x)TiO_(3)材料的低温烧结与介电性能。研究结果表明,Ca_(x)Mg_(1−x)TiO_(3)组成与含量对Ca-B-Si-O玻璃/陶瓷材料的烧结性能、热性能、介电性能有较大影响,适量添加Ca_(x)Mg_(1−x)TiO_(3)可以抑制玻璃析出方石英晶体,而且有利于改善玻璃/陶瓷材料的烧结致密性与介电性能,通过调整x值(摩尔分数x=0.5~1.0)可获得介电性能优良的玻璃/Ca_(x)Mg_(1−x)TiO_(3)材料。Ca-B-Si-O玻璃/CaTiO_(3)材料于875℃烧结试样的综合性能最好,复合材料显微结构致密,ρ为3.17 g·cm^(−3),7 GHz下ε_(r)达到25.18,tanδ为0.0009,满足LTCC材料的性能要求。
[Background and purpose]Glass/ceramic system LTCC materials have excellent properties,such as feasible design and three-dimensional packaging.Functional ceramic films prepared by using tape casting can achieve the functionalization and chip type packaging of microelectronic chips.Borosilicate glass and alumina ceramic materials could be combined to form glass/ceramic LTCC materials with promising sintering performance.In this study,Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) materials were developed with low sintering temperature through regulating the composition and process.Thermal properties,microstructure,low-temperature sintering performance and dielectric properties of the Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) materials with medium dielectric constant were studied for the first time,in order to for high-frequency applications.[Methods]The Ca-B-Si-O glass batches were prepared by using mixing method,followed by melting at 1400–1500℃to produce borosilicate glass.Then,the Ca-B-Si-O glass powder with mean diameter of 3.27μm was obtained through ball milling.The LTCC composite materials were based on 40–55 wt.%Ca-B-Si-O glass and Ca_(x)Mg_(1−x)TiO_(3).The Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) material with high properties was obtained by using low-temperature sintering at 800–925℃,combined with adjustment in composition,structure and firing process.The particle distribution profiles of the Ca-B-Si-O glass and Ca_(x)Mg_(1−x)TiO_(3) powder were measured using NSKC-1 Photo Sizer tester.The DSC curves of glass/Ca_(x)Mg_(1−x)TiO_(3) were recorded using STA449C thermal analyzer.Bulk density of the Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) sintered bodies was measured using Archimedes'method.Phase composition of the Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) sintered bodies was examined using D8 FOCUS X-ray diffractometer.Cross-sectional structures of the Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) sintered bodies were characterized using Zeiss Sigma HD scanning electron microscopy.Dielectric constant and dielectric loss were measured using KEYSIGHT E5080B network analyzer.Coefficient of thermal expansion(CTE)of the sample was measured using DIL 402EP thermal expansion meter over 25–500℃at 5℃·min−1.Three-point bending strength was measured using CMT6208 electronic universal tensile testing machine.[Results]Softening temperature of the Ca-B-Si-O glass is 693℃.With increasing value of x,the softening temperature was gradually increased,while the Tf value of the glass/CaTiO_(3) reached 713℃.Moreover,the shape of the crystallization heat-releasing peak of Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) material varied with the different composite materials.With increasing firing temperature,the bulk density first increased,and then decreased due to the overburning.The transition temperature of different samples is not consistent.The high-temperature molten Ca-B-Si-O glass was homogeneous and totally amorphous.Quartz and wollastonite were crystalized from the Ca-B-Si-O glass at 875℃,while CaTiO(SiO_(4))and CaTiSiO5 crystals were formed in the glass/Ca0.5Mg0.5TiO_(3) and glass/CaTiO_(3) precipitated at 875℃,respectively.Ca-B-Si-O glass can be sintered at 750℃,with a small number of closed pores.As the sintering temperature was increased to 750℃,liquid phase was formed,which led to rapid densification.After sintering at 875℃,relatively smooth cross-section was observed,with a small number of closed pores.The glass/CaTiO_(3) samples had a large number of pores after sintering at 925℃,due to the overburning,thus leading to rapid decrease in density.The maximum dielectric constants were 16.71 and 25.18,for the glass/Ca0.5Mg0.5TiO_(3) and glass/CaTiO_(3),respectively.The Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3) could be sintered at 875℃.The glass/CaTiO_(3) materials with 50 wt.%CaTiO_(3) showed the highest dielectric properties,with densityρof 3.17 g·cm^(−3),dielectric constantεr of 25.18 at 7 GHz,dielectric loss tanδof 0.0009 at 7 GHz,bending strength of 165 MPa and the thermal expansion coefficient of 7.17×10−6℃−1.[Conclusions]The composition of Ca_(x)Mg_(1−x)TiO_(3) has different effects on densification,thermal and dielectric properties of Ca-B-Si-O glass/Ca_(x)Mg_(1−x)TiO_(3).With appropriate Ca_(x)Mg_(1−x)TiO_(3) content,quartz crystals were formed in the Ca-B-Si-O glass,which is beneficial for promoting the sintering density and dielectric properties of glass/ceramic materials.The glass/Ca_(x)Mg_(1−x)TiO_(3) materials with excellent dielectric properties can be obtained through adjusting the value of x(x=0.5–1.0 mole fraction).Especially,the Ca-B-Si-O glass/CaTiO_(3) sample sintered at 875℃exhibited full densification,with a bulk density of 3.17 g·cm^(−3),a dielectric constant of 25.18 at 7 GHz and a dielectric loss of 0.0009,making it potential candidate for low-temperature co-fired ceramics.
作者
刘明
许晓颖
赵拓
周航
马乐嘉
杨家瑞
杨坤
LIU Ming;XU Xiaoying;ZHAO Tuo;ZHOU Hang;MA Lejia;YANG Jiarui;YANG Kun(School of Materials Science and Engineering,Luoyang Institute of Science and Technology,Luoyang 471023,Henan,China)
出处
《陶瓷学报》
北大核心
2025年第3期539-545,共7页
Journal of Ceramics
基金
国家自然科学基金项目(U21A2064)
河南省科技攻关项目(232102231053)
河南省高等学校重点科研项目(22A430031)
河南省本科高校青年骨干教师培养计划项目(2021GGJS164)。
