| abstract |
Powder of a metal serving as a precursor for ceramics (1) and a sintering additive are mixed with each other and heat-treated by microwave heating thereby nitriding or oxidizing the metallic powder from the surface thereof and diffusing the metal with a nitride or an oxide formed on the shell of the metal for obtaining porous ceramics (1) having homogeneous and fine closed pores (1a). The porous ceramics (1) according to the present invention, having the closed pores (1a) homogeneously diffusing at a high ratio, exhibits excellent characteristics when applied to an electronic circuit board or the like requiring moisture absorption resistance, low permittivity and low dielectric loss as well as mechanical strength. |