Method for preparation of sintered body of rare earth oxide
First Claim
1. A method for the preparation of a sintered body of a rare earth oxide which comprises the steps of:
- (a) shaping a powder of the rare earth oxide, of which the D50 value of the particle diameter distribution does not exceed 2.0 μ
m, the D90 value of the particle diameter distribution does not exceed 3.0 μ
m and the specific surface area is in the range from 5 to 20 m2/g, into a powder compact; and
(b) subjecting the powder compact to a heat treatment for sintering at a sintering temperature of 1000°
C. or higher for at least 1 hour, in which the rate of temperature elevation in the range from 500°
C. to the sintering temperature does not exceed 500°
C. per hour and the rate of temperature decrease from the sintering temperature does not exceed 600°
C. per hour.
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Accused Products
Abstract
Disclosed is a method for the preparation of a high-quality sintered body of a rare earth oxide or a composite oxide of a rare earth oxide and an adjuvant oxide such as aluminum oxide. The method comprises shaping a rare earth oxide powder characterized by specified particle diameter distribution values of D50 and D90 and a specified specific surface area or a powder blend of the rare earth oxide and adjuvant oxide into a powder compact and subjecting the powder compact to a sintering heat treatment at a specified sintering temperature by increasing and decreasing the temperature up to and from the sintering temperature each at a rate not exceeding a specified upper limit.
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Citations
17 Claims
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1. A method for the preparation of a sintered body of a rare earth oxide which comprises the steps of:
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(a) shaping a powder of the rare earth oxide, of which the D50 value of the particle diameter distribution does not exceed 2.0 μ
m, the D90 value of the particle diameter distribution does not exceed 3.0 μ
m and the specific surface area is in the range from 5 to 20 m2/g, into a powder compact; and
(b) subjecting the powder compact to a heat treatment for sintering at a sintering temperature of 1000°
C. or higher for at least 1 hour, in which the rate of temperature elevation in the range from 500°
C. to the sintering temperature does not exceed 500°
C. per hour and the rate of temperature decrease from the sintering temperature does not exceed 600°
C. per hour. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for the preparation of a sintered body of a rare earth oxide-based composite oxide with a n adjuvant oxide which comprises the steps of:
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(a) blending a powder of the rare earth oxide, of which the D50 value of the particle diameter distribution does not exceed 2.0 μ
m, the D90 value of the particle diameter distribution does not exceed 3.0 μ
m and the specific surface area is in the range from 5 to 20 m2/g, and an adjuvant oxide of an element selected from the group consisting of magnesium, aluminum, silicon, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, zirconium, niobium, molybdenum, indium, tin, hafnium, tantalum and tungsten to give a powder blend;
(b) shaping the powder blend into a powder compact; and
(c) subjecting the powder compact to a heat treatment for sintering at a sintering temperature of 1000°
C. or higher for at least 1 hour, in which the rate of temperature elevation in the range from 500°
C. to the sintering temperature does not exceed 500°
C. per hour and the rate of temperature decrease from the sintering temperature does not exceed 600°
C. per hour. - View Dependent Claims (16, 17)
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Specification