| 摘要 |
PURPOSE:To obtain the title porous, highly airtight thermal insulating member causing no mechanical strength drop-off by sintering a form produced from a mixture of zirconia powder, partial stabilizer and ceramic powder as fine pore-forming agent followed by coating a ceramics. CONSTITUTION:Firstly, an interim form is made from a mixture of (A) zirconia powder, (B) the first ceramic powder as partial stabilizer and (C) the second ceramic powder as fine poreforming agent. Second, the interim form is heated in a sintering oven and sintered at temperatures not lower than the temperature where zirconia is subjected to phase transition to cubic system, thus producing a base form. Third, the base form is cooled to effect dispersion segregation of tetragonal zirconia crystallites within the base form to partially stabilize the zirconia contained in the base form. Thence, the resulting base form is coated with a ceramics at temperatures not higher than the temperature where the tetragonal zirconia in the base form is subjected to phase transition to cubic zirconia to seal the pores on the surface of said base form, thus obtaining the objective thermal insulating member. |
