The bulk density is more than or equal to 1.82 g/cm3. The Electric resistivity is more than or equal to 9 μ Ω m. The Bending strength is more than or equal to Mpa. The resist compression is more than or equal to 65 Mpa. Ash is more than or equal to 0.1 %. The particle is less than or equal to 43 um(0.043 mm).