Thermal Confuctivity Porous Ceramics

Two sets of highly porous materials with different intrinsic thermal conductivity values for the solid skeleton were prepared.

Thermal confuctivity porous ceramics.

The compressive strength could be improved significantly by increasing the sintering temperature. Gas pressure and temperature dependences of thermal conductivity of porous ceramic materials. Porous ceramics were prepared by different methods to achieve pore volume fractions from 4 to 95. The thermal conductivity of porous alumina ceramics prepared using different types of starch potato wheat corn and rice starch as pore forming agents is investigated from room temperature up to 500 c.

Microstructural characterisation was performed including the determination of the pore size distribution psd. The thermal conductivity of porous alumina ceramics prepared using different types of starch potato wheat corn and rice starch as pore forming agents has been investigated from room temperature up to 500 c. The pore volume fraction was varied from 40 to 75. Thus the reported thermal conductivity and electrical resistivity were 47 270w m k and 100 1011 cm respectively.

In the present study the newly developed porous sic ceramics exhibited a very low thermal conductivity of 0 047 wm 1 k 1 at a high porosity 72 4 that is comparable to the thermal conductivity of sic aerogel 0 049 wm 1 k 1 and even lower than the thermal conductivity 0 068 wm 1 k 1 73 5 porous of a nano sic particle compact without heat treatment. The thermal resistance of tbcs depends not only on the thermophysical properties of the ceramics but also on their microstructure. Starting with a commercial clay containing 75 kaolinite foams were made by mixing in water and methyl cellulose as a surfactant then beating. Zirconia ceramic foams with porosity of 97 9 has low thermal conductivity of 0 027 0 004 w m k 1 which could be used as thermal insulation and refractory material.

Ceramics with low thermal conductivity e g. Zirconia and alumina are generally chosen as tbc top coat material. A clay based material exhibiting high pore volume fraction and low thermal conductivity suitable for thermal insulation is described. Part 2 refractories and ceramics with porosity exceeding 30 efim litovsky laboratory of transport processes in porous materials faculty of mechanical engineering technion israel institute of technology haifa 32000 israel.