High pressure reaction vessel for quality control of diamond growth on diamond seed

Claim 1

In a diamond synthesis reaction vessel for introduction into the reaction volume of a high pressure, high temperature apparatus, said reaction vessel constituting an assembly of interfitting elements for enclosing diamond seed material and a source of substantially pure carbon, said diamond seed material and source of carbon being separated by a mass of metallic catalyst-solvent material for the diamond-making reaction disposed therebetween so as to provide a predetermined temperature gradient between said diamond seed material and said source of carbon under operating conditions of pressure and temperature in the diamond stable region of the phase diagram of carbon, said diamond seed material and said source of carbon being located in separate regions of said reaction vessel such that under said operating conditions said diamond seed material will be heated to a temperature near the minimum value of temperature for said temperature gradient and simultaneously said source of carbon will be heated to a temperature near the maximum value of temperature for said temperature gradient, the combination with said interfitting elements of a. a layer of metallic isolating material disposed in contact with the diamond seed material and between said diamond seed material and the mass of catalyst-solvent material, said isolating material being unpierced where contact is made with said diamond seed material and being selected from the group consisting of platinum, molybdenum, titanium, tantalum, tungsten, iridium, osmium, rhodium, palladium, vanadium, ruthenium, chromium, hafnium, rhenium, niobium and zirconium and alloys thereof and in any given reaction vessel construction said isolating material having a melting point, when in contact with diamond, that is higher than the melting point of the metallic catalyst-solvent material saturated with carbon dissolved therein when in contact with diamond.