YSZ fiber-reinforced porous YSZ ceramics with lowered thermal conductivity: Influence of the sintering temperature

Yttria-stabilized zirconia (YSZ) fiber was introduced to reinforce porous YSZ ceramics fabricated by tert-butyl alcohol (TBA)-based gel-casting process and pressureless sintering. The influence of sintering temperature on microstructure and properties was investigated systematically. Results showed that linear shrinkage of the green bodies during sintering increased and porosity decreased with increasing sintering temperature. Interfacial bonding can be adjusted easily through different sintering temperatures. Compressive strength of the porous YSZ ceramics was improved significantly with the introduction of fibers and the strengthening effect reached its optimum at the sintering temperature of 1500 °C. Compared with the specimens without fiber addition, the compressive strength of fiber-reinforced specimens was almost doubled and the highest reached 45.0 MPa with the porosity of 58.5%. In addition, the thermal conductivity was decreased with the introduction of fibers. The improved mechanical and thermal properties make porous YSZ ceramics more applicable as thermal insulating materials at high temperature.