Fig. 5 shows the accumulated porosity as a function of pore diameter in the cross-section of the specimens at 790 and 10001C. As for the relative density, the porosity was higher for frit PF than frit CF. Measurements of the porosity obtained by image analysis were in good agreement with the relative density values. The average pore diameter (d50) was≅30μm and≅700μm for frits PF and CF, respectively.