PURPOSE: To improve the corrosion-resisting property against plasma as well as to give air permeability to porous silicon carbide plasma dispersing plates by a method wherein said plate is composed of the porous silicon carbide sintered body having the average crystal grain diameter of 0.3W100μm, the density of 1.3W2.3g/cm2, and average bending strength of 1.0kgf/mm2 or more.

CONSTITUTION: As a tabular body having a relatively large area is used for the plasma dispersing plate, the adaptability of handling such as assembling work and the like is an important factor in the manufacture of the title plasma dispersing plate, and the average bending strength of 1.0kgf/mm2 or above is required. The range of average grain diameter of crystal is to be 0.3W100μm. The bonding of each crystal grains of a small sintered body is not so strong, and the pores are small, so they have poor permeability of air, and the grain-to- grain bonded part is made small in the case of the large sintered body, and the strength is reduced. The density in the range of 1.3W2.3g/cm2 forms the bonded part of silicon carbide grains in an excellent condition.