Effect of ZnO addition on properties of cordierite-based glass-ceramics

The influences of addition of ZnO on sintering, crystallization behavior and properties of cordierite-based glass-ceramics were investigated. Results show that with increasing ZnO content, the batch melting temperature, glass transition temperature and crystallization temperature all decrease. Addition of ZnO can greatly improve the sinterability of the glass powders and alter the type of the crystalline phases. Addition of 1.5 wt% ZnO seems to be reasonable. Thermal expansion coefficients (TCEs) of samples increase with increasing ZnO contents. The density was found to be an important factor affecting the dielectric loss of the samples. Dielectric constant and TCEs of the sintered bulk samples were found to depend on their relative densities and crystalline phases. The samples doped with 1.5–3.0 wt% ZnO sintered at 950 °C has a low dielectric constant (5.0–5.2), a low dielectric loss (≤0.0018) and a low thermal expansion coefficient (3.6–4.8 × 10−6 K−1), which are promising electronic packaging materials.