Mullite-alumina composite sintered body and process for producin

Details Mullite-alumina composite sintered body and process for producin Mullite-alumina composite sintered body and process for producin

1988-10-25

1990-10-02

Dixon, Jr., William R.

Compositions: ceramic

Ceramic compositions

Refractory

501 5, 501127, 423328, C04B 3500

Patent

active

049607383

ABSTRACT:
A mullite-alumina composite sintered body composed of from 75 wt % to 85 wt % Al.sub.2 O.sub.3 balance SiO.sub.2, consisting of two crystalline phases, mullite and .alpha.-phase alumina, and being free from glass phase, wherein both of the average diameters of mullite grains and .alpha.-phase alumina grains are not more than 1.0 .mu.m, the content of grains having the longitudinal-length of not less than 2.5 .mu.m is 1% or less in the observation of a cross section of said sintered body, and the porosity of said sintered body is 1% or less.
The sintered body of the present invention is produced by a process comprising the steps of preparing a starting powdery material composed of from 75 wt % to 85 wt % Al.sub.2 O.sub.3 balance SiO.sub.2 and containing amorphous phase from 65 wt % to 90 wt %, wherein each particle of said starting powdery material contains both Al.sub.2 O.sub.3 and SiO.sub.2, and sintering said starting powdery material at a temperature in the range from 1500.degree. C. to 1650.degree. C.
The sintered body of the present invention has a high bending strength exceeding 500 MPa at room temperature.

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