| 摘要 |
<p>PURPOSE:To facilitate the initial impregnation of a filter medium with an introduced molten metal, to ensure the amt. of the molten metal to be passed and to collect fine inclusions by making the average pore diameter of the filter medium consisting of a ceramic aggregate grain and an inorg. binder on the inlet side larger than that on the outlet side. CONSTITUTION:In the case of a plate-shaped filter medium, an appropriate amt. of the inorg. binder contg. Al2O3, B2O3, CaO and MgO in a specified ratio is separately added to the two kinds of zirconia-based ceramics having different average grain size, and the mixture is kneaded with an org. binder such as dextrin. The obtained admixtures are respectively charged into a metallic mold in a desired thickness ratio, compression-molded, dried and then sintered to prepare a plate-shaped filter medium for molten metal with the average pore diameter varied in the thickness direction.</p> |
