Process for the synthesis of diamond
AssigneeSumitomo Electric Industries, Ltd.
InventorsShuichi Satoh, Hitoshi Sumiya, Kazuwo Tsuji, Yasushi Gouda
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Abstract
A colorless and transparent, substantially inclusion-free diamond crystal which can be applied to decorative uses and optical parts is synthesized by a process using a temperature gradient method in an ultra-high pressure apparatus. This process comprises using, as a solvent for the growth of the crystal, at least one metal selected from the group consisting of Fe, Co, Ni, Mn and Cr (at least two metals in the case of containing Fe) and as a nitrogen getter for the removal of nitrogen in the solvent, at least one metal selected from the group consisting of Al, Ti, Zr, Hf, V, Nb and Ta in a proportion of 0.5 to 7% by weight (at most 2% by weight when using only Al) to the solvent metal.
Claims12
In a process for synthesis of colorless and transparent diamond single crystals containing metal in an amount of at most 0.5 weight %, N in an amount of at most 0.1 ppm and B in an amount of 0.1 to 0.6 ppm by the temperature gradient method which employs diamond as a carbon source, a solvent metal and a seed crystal, wherein the carbon source is separated from the seed crystal by a solvent metal, wherein said carbon source dissolves in said solvent metal upon heating, a temperature gradient exists between the carbon source and seed crystal and temperature and pressure are such as to permit diamond crystal growth on said seed crystal, the improvement consisting essentially of:
- (a) a solvent for crystal growth of an alloy containing Fe and at least one member selected from the group consisting of Co, Ni, Mn and Cr, said solvent further containing 0.1 to 6 wt. % carbon;
- (b) a nitrogen getter for removing nitrogen in the solvent of at least one metal selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta, in a proportion of from 0.5 to 7% by weight based on the solvent;
- (c) a low viscosity element which is at least one member selected from the group consisting of Al, Sn, In, Ga, Ag, Cu, Cs, Pb, Sb and Zn, in an amount of from 0.5 to 3% by weight based on the solvent and
- (d) the crystal growth rate being higher than 2 mg/hr.
In a process for the synthesis of diamond single crystals containing metal in an amount of at most 0.5 weight % by the temperature gradient method which employs a carbon source, a solvent metal and a seed crystal, wherein the carbon source is separated from the seed crystal by a solvent metal, wherein said carbon source dissolves in said solvent metal upon heating, a temperature gradient exists between the carbon source and seed crystal and temperature and pressure are such as to permit diamond crystal growth on said seed crystal, the improvement which comprises contacting said solvent metal of at least one member selected from the group consisting of Fe, Co, Ni, Mn and Cr with said carbon source, arranging at least one metal selected from the group consisting of Ti, Zr and Hf as a nitrogen getter at the solvent metal side between the solvent metal and said seed crystal disposed below the solvent metal and arranging Al at the seed crystal side between the nitrogen getter and the seed crystal in such a manner that the seed crystal is not contacted with the nitrogen getter.
In a process for the synthesis of diamond single crystals containing metal in an amount of at most 0.5 weight % by the temperature gradient method which employs a carbon source, a solvent metal and a seed crystal, wherein the carbon source is separated from the seed crystal by a solvent metal, wherein said carbon source dissolves in said solvent metal upon heating, a temperature gradient exists between the carbon source and seed crystal and temperature and pressure are such as to permit diamond crystal growth on said seed crystal, the improvement which comprises contacting said solvent metal of at least one member selected from the group consisting of Fe, Co, Ni, Mn and Cr with said carbon source, arranging at least one metal selected from the group consisting of Al, Ti, Zr and Hf as a nitrogen getter at the solvent metal side between the solvent metal and said seed crystal disposed below the solvent metal and arranging Sn at the seed crystal side between the nitrogen getter and the seed crystal in such a manner that the seed crystal is not contacted with the nitrogen getter.
Dependencies are inferred from the claim text.