Sintering behaviors, microstructure and properties of Li2O–Al2O3–SiO2 glass-ceramics for LTCC applications

Abstract

When preparing glass-ceramics using sintering method, porosity is the main reason affecting their properties. To achieve glass-ceramics with low thermal expansion performance, cold isostatic pressing is adopted to significantly reduce the porosity. In this study, we systematically analyzed the effect of CaF₂/CaO content on sintering behavior, microstructure and properties of Li₂O–Al₂O₃–SiO₂ (LAS) glass-ceramics. It was found that the [CaF₂]/([CaO]+[CaF₂]) ratio x can be used to regulate the coefficient of thermal expansion (CTE) of the LAS glass-ceramics. The optimized sample has a CTE of 2.2865 ppm/°C, which is compatible with that of silicon (2.5 ppm/°C). At the same time, low dielectric constant (5.95 ≤ ε_r ≤ 8.89) and dielectric loss (1.179 × 10⁻³ ≤ tanδ ≤2.871 × 10⁻²) were observed, which makes them a promising candidate for low-temperature co-fired ceramic substrate applications.