| 摘要 |
PURPOSE:To prevent a contact between a beta-alumina tube and a protection tube to obtain a product which has a fine appearance without any trace by putting inversely a cylindrical beta-alumina tube basis, having a bottom on which a foil made by platinum group element is covered as spanning the necessary length of the bottom side, on a baking support and leaving a necessary space to cover the abovementioned beta-alumina tube basis with a baking protection tube. CONSTITUTION:A necessary space between a beta-alumina tube basis 1 and a baking protection tube 5 is left for covering the baking protection tube 5 on a baking support 4, and the beta-alumina tube basis 1 in the state of covered with the baking protection tube 5 is baked at about 1620 deg.C in a gas furnace. At that time, a burning shrinkage of 16-20% of beta-alumina tube basis is generated. The baking protection tube 5 is constructed by a spinel ceramic tube containing a mixture of magnesia and alpha-alumina and so on. Moreover, the closed upside from an inner bottom 2 of the inversely put beta-alumina tube basis is covered by a metallic foil 6 made by platinum group element to prevent a direct contact between the beta-alumina tube basis 1 and the baking protection tube 5. |
