Preparation method of artificial diamond synthesis graphite core column

Abstract

The invention discloses a preparation method of an artificial diamond synthesis graphite core column. The preparation method is characterized by comprising the steps that cementite is firstly prepared, and then the prepared cementite is implanted into graphite alloy accelerant powder to prepare the graphite core column. The cementite is implanted into the powder accelerant core column, in the external environment that under the conditions of the high temperature and the high pressure, crystallization and nucleation are preferentially achieved in the cementite, and co-solution and co-diffusion are achieved at the same time, due to the density potential and the chemical potential, carbon atoms and a metal accelerant are enriched towards the periphery of the cementite, and the growth continuity of diamond crystals in the cementite is guaranteed; and in addition, the implanting proportion of the cementite is controlled, and therefore diamond crystallization and nucleation are controlled, then the grain size is controlled, and the aim of diamond growth controllability is achieved. According to the method, the problem of diamond carbonization and the impurity discharge problem existing in the seeding method are avoided, meanwhile, a high-quality accelerant alloy is used in cementite preparation, and therefore the content of precious metal in the graphite accelerant powder can be reduced correspondingly, and the production cost can be reduced.

Description

technical field [0001] The invention relates to the technical field of synthesis and production of superhard materials, in particular to a method for preparing a graphite core column for synthetic diamond synthesis. Background technique [0002] Powder catalyst technology is the main method for synthesizing graphite core pillars for superhard materials, and the essence of industrial growth of diamond crystals is the growth of iron-nickel-carbon melt, namely cementite, under high temperature and pressure, so cementite is a prerequisite for growing diamond condition. However, in the synthesis and production process of diamond, in the stage of co-dissolution and co-infiltration of catalyst graphite, due to the disorder and uncontrollability of the formation of cementite, the nucleation and growth of diamond are accidental and aimless. [0003] Although seed crystal growth achieves the controllability of diamond growth by implanting diamonds with specific crystal forms and part...

AI Technical Summary

Problems solved by technology

However, in the process of diamond synthesis and production, in the stage of catalyst graphite co-dissolution and co-infiltration, due to the disorder and uncontrollability of cementite formation, the nucleation and growth of diamonds are accidental and purposeless.

[0003] Although seed crystal growth achieves the controllability of diamond growth by implanting diamonds with specific crystal forms and particle sizes, the cost of seed crystal implantation is relatively high, and because diamond seed crystals have oxidation and carbonization problems at high temperatures, And the interface contact between the diamond seed crystal interface and the iron-nickel-carbon melt before formation leads to discontinuity in growth, which may cause impurity problems during the crystal growth process, which in turn leads to the generation of inclusions or internal impurities, affecting the synthesis effect and Crystal quality is not conducive to the promotion and application of products

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