A method of growing large-grain diamond under high temperature and high pressure

Abstract

The invention provides a method for growing large-grain diamonds under high temperature and high pressure, using seed crystals, catalysts, and carbon sources as raw materials. The process steps are as follows: (1) placing the crystal seeds in the catalyst and molding them to obtain a composite of catalyst-wrapped seed crystals body, and then wrap the complex with a carbon source to form a diamond growth body; (2) combine the diamond growth body obtained in step (1) with the high-temperature and high-pressure device matched with the static high-pressure equipment to form a synthetic block, and then put the synthetic block into In the static high-pressure equipment, the pressure is first increased to the diamond growth pressure, and then the temperature is raised to the diamond growth temperature, and the pressure is maintained for growth; (3) After the pressure-holding and heat preservation is completed, the temperature is first lowered to room temperature, and then the pressure is reduced to normal pressure, and then the static high-pressure equipment is returned. And take out the block of diamond covered by the remaining carbon source and catalyst, and remove the remaining carbon source and catalyst of the block to obtain diamond. The method can provide carbon sources for diamond growth from multiple directions, and improve the growth rate of diamond and the output rate of diamond large single crystal.

Description

A method for growing large-particle diamond under high temperature and high pressure technical field The invention belongs to synthetic diamond technical field, relate to the method for growing large particle diamond under high temperature and high pressure. Background technique Diamond has physical properties such as high hardness, high thermal conductivity, low expansion coefficient, and is used in machining, oil drilling Detection, electronic devices, defense and military industry, medical equipment, jewelry and other fields. The performance of synthetic diamond single crystal has been comparable to Comparing with natural diamond, doped diamond even far exceeds natural diamond in some physical properties. About the synthesis of large particle synthetic diamond, what is generally adopted at present is temperature gradient method, utilizes catalyst at high temperature The carbon source is converted into diamond crystals under high pressure. In the temperature grad...

AI Technical Summary

Problems solved by technology

Therefore, the temperature gradient method has the following problems: (1) It can be seen from the positional relationship of carbon source, catalyst, and seed crystal that in the process of diamond growth, the carbon source can only carry out carbon atom transfer through the catalyst in one direction, so the transfer of carbon The efficiency is low, which affects the growth rate of diamond and increases the growth time and cost of diamond crystal; (2) Since there must be a suitable temperature difference ΔT between the carbon source and the seed crystal, the carbon source, catalyst, and seed crystal The assembly design is limited, and the assembly is difficult; (3) Since the seeds have different crystal planes, and under the same temperature and pressure conditions, different crystal planes grow at different speeds, such as crystal planes (111) and (100 ) is more dominant than other crystal planes. Therefore, when the temperature gradient method is used to grow diamond single crystals, it is also necessary to consider that the crystal plane with the growth advantage of the seed crystal is perpendicular to the direction of carbon source transport. Distinguish between different surfaces, which not only further increases the difficulty of assembling carbon sources, catalysts, and seed crystals, but also reduces the output rate of large diamond single crystals

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