Crystallization behaviors of R2O–Al2O3–SiO2 glass–ceramics for use as anodic bonding materials

In this work, the crystallization behaviors of R2O–Al2O3–SiO2 (R means K, Na and Li) glass–ceramics which was used as anodic bonding materials were discussed. The glass–ceramics with P2O5 as nucleation agents were investigated by means of differential scanning calorimeter (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and coefficient of thermal expansion (CTE) tests. The test results have shown that: the DSC trace of parent glass has two different precipitation crystallization peaks corresponding to formation the crystal phases of Li2Si2O5 and Li2SiO3. According to the selected heat treatment schedules, the Li2SiO3 crystal phases changed into Li2Si2O5 while the crystallization temperature at 650 °C in glass–ceramics; on the contrary, the Li2Si2O5 crystal phases can be decomposed into Li2SiO3 at the crystallization temperature of 850 °C. The coefficients of thermal expansion with R2O–Al2O3–SiO2 glass–ceramics about 119–140 × 10−7/°C at 450 °C, which could be nearly matched that of stainless steel (No. 430#).

Research highlights▶ R2O–Al2O3–SiO2 (R means K, Na and Li) glass-ceramics, instead of traditional hot-resistant glass was used as anodic bonding materials. ▶ According to the selected heat treatment schedules, the Li2SiO3 crystal phases changed into Li2Si2O5 while the crystallization temperature at 650 °C in glass-ceramics; but the Li2Si2O5 crystal phases can be decomposed into Li2SiO3 at the crystallization temperature of 850 °C. ▶ The coefficients of thermal expansion with R2O–Al2O3–SiO2 glass-ceramics about 119–140 × 10−7/°C at 450 °C, which could be nearly matched that of stainless steel (No. 430#).