| 摘要 |
PURPOSE:To raise the impact resistance and wear resistance of a stamp as well as obtain clear stamp figure by forming the stamp from a sintered zirconia material of tetragonal crystal structure. CONSTITUTION:At least the stamp figure portion of a stamp is made of zirconia of tetragonal crystal structure containing at least 50mol% zirconia or of monoclinic crystal structure containing 10mol% or less zirconia. In the manufacture of the stamp, high-purity zirconium chloride is mixed with 10mol% or less one of calcium chloride and magnesium chloride, etc. The mixture solution is dried, calcined, and wet-ground in a repeated manner. During the process, the chloride containing zirconium oxychloride is converted into oxide. A binder (e.g., polyvinyl alcohol) is added to the powder so formed, wet-mixed, granulated, dried, and molded into a desired molding by a well-known molding method. The molding is baked at a given temperature and cooled to obtain a sintered zirconia molding of a desired form. |
