2.3. Preparation of specimens and experimental procedure
The specimens were produced by pouring CF and PF into a cylindrical mullite mold (40 mm diameter, 40 mm height) over a cordierite plate of 10 mm thickness, (A) and (B) in Fig. 2, respectively. The internal walls of the molds were coated with a thin layer of refractory magnetite-based engobe (C) that was applied by slip casting. The PF and the CF frits were put into the mold by slip casting (80 wt% solid content) and dry casting, respectively. In each mold, 40 g of frit (dry basis) was used. After the molds werefilled, the frits were dried in a stationary laboratory dryer at 801C for 24 h.