Polycrystalline transparent spinel sintered body and method of producing the same
AssigneeNGK Insulators, Ltd.
InventorsMinoru Matsui, Tomonori Takahashi
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Abstract
The disclosed polycrystalline transparent sintered body contains Al.sub.2 O.sub.3 and MgO at a molar ratio of (0.54:0.46) to (0.58:0.42) and has an in-line transmittance of more than 77% for 1 mm thickness at a light wavelength of 0.6 .mu.m, which sintered body is produced by preparing fine spinel powder through hydrolysis of an isopropanol solution of aluminum isopropoxide and magnesium isopropoxide, forming a shaped body from the powder, and sintering the shaped body.
Claims9
A polycrystalline transparent spinel sintered body, consisting of Al.sub.2 O.sub.3 and MgO in a ratio of (0.54:0.46) to (0.58:0.42), said sintered body having an in-line transmittance of at least 77% for a 1 mm thickness at a light wavelength of 0.6 .mu.m.
A polycrystalline transparent spinel sintered body, consisting of Al.sub.2 O.sub.3 and MgO in a ratio of (0.54:0.46) to (0.58:0.42), said sintered body having an in-line transmittance of at least 77% for a 1 mm thickness at a light wavelength of 0.6 .mu.m made by a method comprising the steps of preparing an isopropanol solution of aluminum isopropoxide and magnesium isopropoxide, generating precipitates by hydrolosis of the isopropanol solution, heating said precipitates to form a fine spinel powder consisting of Al.sub.2 O.sub.3 and MgO in a molar ratio of (0.502:0.498) to (0.524:0.476), shaping a body from said formed powder and firing the shaped body in a hydrogen atmosphere at a temperature higher than 1700.degree. C. to obtain said ratio of Al.sub.2 O.sub.3 and MgO in said sintered body.
A polycrystalline transparent spinel sintered body, consisting of Al.sub.2 O.sub.3 and MgO in a ratio of (0.54 :
- 0.46) to (0.58 :
- 0.42) and LiF in an amount less than 0.01% by weight, said sintered body having an in-line transmittance of at least 77% for a 1 mm thickness at light wavelength of 0.6 .mu.m.
Dependencies are inferred from the claim text.