Effect of SrO Content on Structure, Thermal Properties and Chemical Stability of Bi₂O₃-B₂O₃-ZnO-SrO Low-melting Glass for Si-Al Alloy Package

Abstract

The 40Bi₂O₃-30B₂O₃-(30−x)ZnO-xSrO (x=0–15mol%, BBZSr) glass system was prepared by the conventional melt quenching method. The effect of SrO addition on structure, thermal properties, chemical stability and sealing performance of BBZSr glass were investigated thoroughly. The experimental results show that the total proportions of [BO₃] group and [BO₄] group decrease and the vibrations of [BiO₃] group and [BiO₆] group become weaker with the increase of SrO addition content, suggesting the glass network structure is strengthened owing to the SrO addition. Hence, both the thermal and chemical stability were significantly improved as the SrO content was increased. When the SrO content increased from 0 to 15mol%, the glass transition temperature and softening temperature slightly increased from 380 to 388 °C and from 392.7 to 402.2 °C, respectively, meanwhile the coefficient of thermal expansion also increased from 10.49×10⁻⁶ to 11.16× 10⁻⁶/°C (30–300 °C). The BBZSr glass with 15mol% SrO exhibited excellent comprehensive properties with low glass transition temperature(384.9 °C), low softening temperature(400.3 °C), high coefficient of thermal expansion (11.14×10⁻⁶ C, 30–300 °C), good thermal and chemical stability. Besides, the glass had the good wetting behavior and sealing performance for Al-50%Si alloy.

Keywords

low-melting sealing lead-free glass / Bi₂O₃-B₂O₃-ZnO-SrO glass / silicon-aluminium alloy / thermal expansion