| 摘要 |
Alumina is grown on a seed from solution in a solvent comprising lead oxide and fluoride, loss of lead fluoride being prevented by means of a reflux condenser. A shield 10 (Fig. 1, not shown) may prevent refluxed drops of lead flouride from disturbing the growing crystal. Alternatively, the reflux may be returned to a second vessel 7 (Fig. 2, not shown) in vapour communication with a crystallization vessel 6. The vessels may be tiltable so that reflux returns to crystallization vessel 6 during heating (Fig. 3, not shown) and to second vessel 7 during cooling (Fig. 4, not shown).ALSO:Alumina is grown on a seed from solution in a solvent comprising lead oxide and fluoride, loss of lead fluoride being prevented by means of a reflux condenser. A shield 10 (Fig. 1, not shown) may prevent refluxed drops of lead fluoride from disturbing the growing crystal. Alternatively, the reflux may be returned to a second vessel 7 (Fig. 2, not shown) in vapour communication with a crystallization vessel 6. The vessels may be tiltable so that reflux returns to crystallization vessel 6 during heating (Fig. 3, not shown), and to second vessel 7 during cooling (Fig. 4, not shown). |
