| 摘要 |
719,611. Making sintered refractory bodies. LORD PRESIDENT OF THE COUNCIL. Aug. 15, 1949 [Aug. 30, 1948], No. 22807/48. Class 87(2) Shaped sintered bodies of refractory compounds are joined to each other by pressing them together whilst they are at a sintering temperature, the pressure applied being of the order of 1 ton p.s.i. The refractory compounds maybe oxides of beryllium, aluminium, thorium and magnesium. Individual bodies are made from such oxides by compaction at a sintering temperature and then these bodies are joined by pressing at a sintering temperature: the second sintering temperature may be the same as the first, or when dissimilar bodies produced at different temperatures are being joined the second sintering temperature may be the lower or lowest of said different temperatures. The drawings show apparatus for making two hemispheres and sticking them together, comprising a mould 8a and plunger 9a for forming the hemispheres and two plungers 9, 17 for sticking them together in a mould 8b. The moulds and the plunger ends are coated with graphite in acetone. In both steps of the procedure the mould rests on a graphite block 6, sheets 5, 3 of " Sindanyo " (R.T.M.)-mainly asbestos, and lower platen 1 of a hydraulic press. The mould is surrounded by magnesia 14 packed within a tube 4 of silica or alumina surrounded by a high frequency heating coil 10 in a mica shell 11. A graphite plunger 9 enters the mould and pressure is applied thereto from the upper platen 2 through a block 18. A graphite tube 13 receives a pyrometer. Both pressings may be at 1,500‹C. and 1 ton p.s.i. for 10 minutes. Hollow hemispheres may be made similarly and then stuck together around a solid sphere.
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