Claims
- 1. In a process for manufacturing articles of translucent alumina by sintering articles molded from a very pure fine powder containing a small portion of a grain-growth inhibiting substance, comprising the steps of:
- a. preliminarily sintering said powder in an oxidizing atmosphere at a temperature between about 700.degree. C and about 1100.degree. C., followed by
- b. final sintering at a temperature above 1700.degree. C., in a nonoxidizing medium, the improvement which comprises conducting final sintering in a carbon monoxide atmosphere.
- 2. The process of claim 1, wherein the preliminary sintering takes place at a temperature of from 800.degree. to 1100.degree. C.
- 3. The process of claim 1, wherein the final sintering takes place under a partial carbon monoxide pressure above or equal to 670 millibars.
- 4. The process of claim 3, wherein the final sintering takes place at about 1850.degree. C for about 5 hours.
- 5. The process of claim 1, wherein the final sintering takes place in a carbon monoxide atmosphere containing an inert gas.
- 6. The process of claim 1, wherein the final sintering takes place in a carbon monoxide atmosphere in the presence of carbon.
Priority Claims (2)
Number |
Date |
Country |
Kind |
69.37585 |
Oct 1969 |
FR |
|
71.28434 |
Aug 1971 |
FR |
|
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 273,581, filed July 20, 1972 which is a continuation-in-part application of our earlier co-pending application Ser. No. 84,456, filed Oct. 27, 1970 and both now abandoned and claiming priority from Oct. 31, 1969, based on French Pat. No. PV No. 69 37 585.
US Referenced Citations (6)
Continuations (1)
|
Number |
Date |
Country |
Parent |
273581 |
Jul 1972 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
84456 |
Oct 1970 |
|