Effects of TiO2 on microstructures and properties of Li2O–Al2O3–SiO2 glass–ceramics for LTCC substrates

Abstract

In order to increase the flexural strength and to adjust the coefficient of thermal expansion (CTE), TiO2 was introduced into Li2O–Al2O3–SiO2 (LAS) glass–ceramics to satisfy LTCC applications. The effects of TiO2 addition on the microstructure, thermal, mechanical and electrical properties were studied. The results showed that the crystal phases were composed of Li2OAl2O37.5SiO2 (major), as well as TiO2 and CaMgSi2O6 (minor). The crystal phase TiO2 having higher CTE value could appropriately increase the CTE value of LAS to fit the silicon and remarkably improve the flexural strength of LAS glass–ceramic with low CTE. The dielectric and insulating properties also strongly depended on the amount of TiO2. LAS glass–ceramic sintered at 800 °C with high performances was achieved in the case of 1 wt% TiO2: α = 2.56 × 10−6/°C, σ = 151 MPa, e = 6.8, tanδ = 1.731 × 10−3, ρ = 8.29 × 1010 Ω cm.