Thermo-mechanical properties of bio-insulation from embedding bird eggshell into ceramics for bioengineering applications

Incorporating bird eggshell in porcelain can improve its physical, thermal, and mechanical properties, resulting in dense porcelain products. Calcium carbonate (CaCO3) from eggshells can react with silica (SiO2) and alumina (Al2O3) in porcelain clay to form calcium feldspar or anorthite (CaAl2Si2O8), which lowers the sintering temperature to <1000 °C. In this study, 0, 5, 10, 15, and 20 vol.% bird eggshell powder was added to porcelain slips and fired at 600, 700, 800, and 900 °C for 1, 3, and 5 h. The best formula of porcelain product having good mechanical and thermal properties was obtained at 10 vol.% quail eggshell-added porcelain fired for 5 h at 900 °C. The obtained sample demonstrated a relatively low thermal expansion coefficient (1.0515x10-6 °C-1), high compressive strength (6200 N mm-2), and high hardness (12.2 ± 0.30 HV).