Preparation and properties of crystallizable Glass/Al₂O₃ composites for LTCC material

Abstract

The investigated low temperature Co fired ceramics(LTCC) composite of 60wt% CaO-Al₂O₃-B2O₃-SiO₂ glass and 40wt% α-Al₂O₃ as a filler is a non-reactive system, which is a critical part of the low temperature Co fired ceramics process. Through a study on densification process, the phase transformation and microstructure can be revealed. Its composites typically consist of CaO-Al₂O₃-B₂O₃-SiO₂ glass and α-Al₂O₃ powders of average particle size (D ₅₀=3.49 μm). The sintering behavior, phase evaluation, sintered morphology, and microwave dielectric properties were investigated. In the fire range of 800 to 900 °C, the composites were crystallized after completion of densification. It is found that the composites start to densify at 825 °C, simultaneously, the dielectric constant (ɛ _r) reaches its maximum. With increasing heat-treatment temperatures, due to the loose microstructure of the material, tanδ increases slightly. The last of the sintered samples were identified as partly Anorthite at 850 °C. At that temperature it has ɛ _r of 7.9 and tanδ less than 1×10⁻³, and can be used as a promising LTCC material.

Keywords

glass-ceramics / densification / precipitation / LTCC materials

References

[1] Higuchi Y., Sugimoto Y., Tamura H. LTCC System with New High- r and High-Q Material Co-fired with Conventional Low-ɛ_r Base Material for Wireless Communications [J]. J. Eur. Ceram. Soc., 2007, 27: 2785-2788.

[2] Cui X., Zhou J. A Simple and an Effective Method for the Fabrication of Densified Glass-ceramics of Low Temperature co-fired Ceramics [J]. Mater. Res. Bull., 2008, 43: 590-1597.

[3] Zhu H.Q., Zhou H.Q. Preparation and Properties of Lowtemperature Co-fired Ceramic of CaO-SiO₂-B₂O₃ System[J]. Mater. Sci: Mater Electron., 2006, 17: 637-641.

[4] Chiang C.-C., Wang S.-F., Wang Y.-R., Wei W.-C. J. Densification and Microwave Dielectric Properties of CaO-B₂O₃-SiO₂ System Glass-Ceramics[J]. Ceramics International, 2008, 34: 599-604.

[5] Valant M., Suvorov D. Microstructural Phenomena in Low-firing Ceramics[J]. Mater. Chem. Phys., 2003, 79: 104-110.

[6] Wang S.H., Zhou H.P. Densification and Dielectric Properties of CaO-B₂O₃-SiO₂ System Glass Ceramics[J]. J. Mater. Sci. Eng., 2003, 99: 597-600.

[7] Cheng C.C., Hsieh T.E., Lin I. N. Microwave Dielectric Properties of Glass-ceramic Composites for Low Temperature co-firable Ceramics [J]. J. Eur. Ceram. Soc., 2003, 23: 2553-2558.

[8] Jung B.H., Hwang S.J., Kim H.S. Glass-ceramic for Low Temperature Co-fired Dielectric Ceramic Materials based on La₂O₃-B₂O₃-TiO₂ Glass with BNT Ceramics[J]. J.Eur Ceram. Soc., 2005, 25: 3187-3193.

[9] Hunag C. L., Weng M. H., Lion C. T., Wu C. C. Low Temperature Sintering and Microwave Dielectric Properties of Ba₂Ti₉O₂₀ Ceramics Using Glass Additions[J]. J. Eur. Ceram. Soc., 2000, 35: 2445-2456.

[10] Imanaka Y. Multilayered Low Temperature Cofired Ceramics (LTCC) Technology [J]. Ceramic Material, 2005, 2: 21

[11] Nishigaki S., Fukuta J. Low-temperature Cofirable Multilayered Ceramic Bearing Pure-Ag Conductors and Their Sintering Behavior[J]. Advances in Ceramics, 1989, 26: 199-215.

[12] Lim W. B., Saji V.S. Crystallization and Dielectric Properties of Low Temperature Dielectrics Containing Li₂O Filler[J]. J. Non-Crystalline Solids, 2008, 354: 3 849-3 853.

[13] Kemethmuller S., Hagymasi M., Stiegelschmitt A., Roosen A. Viscous Flow as the Driving Force for the Densification of Low-temperature Co-tired Ceramics[J]. J. Am. Ceram. Soc., 2007, 90: 64-70.