| 摘要 |
<PICT:0872286/III/1> Corundum (a -alumina) is prepared by heating aluminium fluoride in air, oxygen, or an oxygen-containing gas, having a humidity of 10-16 to 105 mg. water per litre to a temperature in the range 700 DEG C.-1000 DEG C., the temperature being sufficiently high for a given humidity for corundum to be formed. Preferably the moist gas is passed over or through the heated aluminium fluoride. The reaction normally takes several hours. The accompanying graph shows a typical temperature-humidity relationship. |
