Highly Porous Zirconia Ceramic Foams with Low Thermal Conductivity from Particle-Stabilized Foams

Zirconia ceramic foams with ultra-high porosity of 96%-98% have been fabricated using sodium dodecyl sulfate (SDS) as the particle stabilizer of zirconia particles for the first time. The wet foams stabilized by zirconia particles are ultra-stable due to partially hydrophobic zirconia particles modified by SDS. Zirconia foams exhibit close cells with thin cell wall and small grain size. Increasing SDS concentration favors the foamability of the suspension, and further increases the porosity of ceramic foams. Zirconia ceramic foams with porosity of 98.1% have compressive strength of 0.26 +/- 0.05 MPa. Decreasing solid loading leads to the porosity of ceramic foams. The compressive strength could be improved significantly by increasing the sintering temperature. Zirconia ceramic foams with porosity of 97.9% has low thermal conductivity of 0.027 +/- 0.004 W(mK)(-1), which could be used as thermal insulation and refractory material.