| 摘要 |
A piston type system for forming industrial diamonds is provided with a pressure vessel which includes a tungsten carbide member having a central opening which has a tapered mouth at one end, and which is lined with a salt bushing. A charge including invar and graphite to be converted to diamond is inserted within the pressure chamber inside the salt bushing. An end load plate has a central opening of substantially the same diameter as the opening in the salt bushing and has a tapered flange which fits into the tapered mouth in the tungsten carbide pressure vessel. A tungsten carbide piston which has a diameter about 0.003 inch less than the diameter of the opening in the end plate, and which has a lead gasket between its surface and that of the opening in the end plate, is forced through the end plate and applies high pressure at high temperatures to the charge, thereby converting the graphite to diamond after the passage of a suitable period of time. The tungsten carbide piston need only have the diameter of the inner diameter of the salt bushing, instead of a diameter equal to the full I.D. of the tungsten carbide pressure vessel.
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