| 摘要 |
<p>1397974 Transparent alumina CERAVER 26 July 1972 [3 Aug 1971] 35049/72 Addition to 1292401 Heading C1A An article of transparent alumina is produced by forming an article of Al 2 O 3 powder containing 0À02-0À6% MgO or a precursor thereof, prefiring in an oxidizing atmosphere at above 700‹ C., and sintering at above 1700‹ C. in air atmosphere containing CO and additionally in the presence of free carbon. The carbon may be introduced as powdered graphite or as decomposable carbon compounds, or may be present in the furnace parts, e.g. the susceptor or resistor may be made of graphite or refractory carbides.</p> |
