| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sintered compact mainly comprising SiO2 and hardly having defects by specifying the unit-area number of pores having a diameter of a specific value or larger in an arbitr cross section and making the pores substantially nonspherical. SOLUTION: This sintered compact has <=10/cm2 of the number of pores having a diameter of >=50μm. SiO2 powder having an average particle diameter of preferably 0.05-5μm is formed to have a specific shape. The forming procedure is conducted in any one of dry forming and wet formin An SiO2 formed product is baked in any one of the atmosphere, a vacuum and a non-oxidative atmosphere. The baking temperature is preferably 1,250 deg.C when the average diameter of SiO2 powder is 0.05μm and 1,550 deg.C when the average diameter of SiO2 powder is 5μm. Pyrolytic treatment of an organic binder in the SiO2 formed product is performed at 350-700 deg.C before baking, if necessary. The shape of the pore is substantially nonspherical and has ruggedness on its surface. The surface of the sintered compact is formed mainly of a cristobalite crystal phase and is high in breaking strength. The sintered compact is expected to have a wide variety of uses in the field of quartz glass.
|
