Crystallization, densification and dielectric properties of CaO–MgO–Al2O3–SiO2 glass with ZrO2 as nucleating agent

• ZrO2 effects on the crystallization of LTCC glass system were investigated.
• ZrO2 effects on the dielectric properties of LTCC glass system were investigated.
• LTCC with a dielectric constant of 6.65 and a low dielectric loss can be obtained.

The zirconium oxide effects on the crystallization and dielectric properties of CaO–MgO–Al2O3–SiO2 (CMAS) glass were investigated. The results showed that phyllosiloxide and anorthite crystallites were observed in sequence during sintering. For glass added with 8 wt% ZrO2, homogeneously dispersed tetragonal ZrO2 crystallites were observed at 850 °C. The as-prepared CMAS glass–ceramics exhibited a dielectric constant of about 6–7 and a dielectric loss below 0.005 at 100 MHz. The dielectric properties of CMAS glass with 8 wt% ZrO2 sintered at 850 °C show a low dielectric constant of 6.65 and a dielectric loss tangent of about 2.5 × 10−3, which provides a promising candidate for LTCC applications.

Figure optionsDownload as PowerPoint slideSEM micrographs for the pure CaO–MgO–Al2O3–SiO2 glass sintered at 850–1000 °C (a) 850 °C, (b) 900 °C, (c) 950 °C, (d) 1000 °C.