2020 Volume 67 Issue 11 Pages 601-606
Unidirectional anisotropic pore morphologies could be created by using a gelation of mullite particles dispersed slurry with and without an anti-freezing protein additive, and the freezing process, resulting in micrometer-sized cells with very high porosities of up to 91 vol%. The addition of ice binding proteins effectively inhibited the formation of coarse ice crystals, reduced the resultant cell size and provided uniform size distribution in insulators obtained. The insulators prepared showed the thermal conductivity from 0.23 to 0.38 W/mK and the compressive strength around 1.4–21.7 MPa. These properties could be modulated by varying process parameters of the gelation and freezing with solid loading in the initial slurry, anti-freezing protein, sintering additive. This unique approach can be used to produce insulators with macro-cellular anisotropic morphology and very high porosity, suitable for a variety of industrial applications.
