Synthesis Of Industry Diamond Single Crystals By Spontaneous Coring And Seeds Extension

Since diamond was first synthesized by a General Electric research group from graphite and metal catalyst at static high pressures and high temperatures (HPHT) in 1955, diamond synthesis has attracted much attention worldwide because of their potential economical competitiveness for many applications. The subsequent rapid development of superhard materials syntheses to the current level is mainly contributed by the continual improvement and perfection of static high pressure apparatus and the finding of a series of transition metals and alloys. The superhard materials have many applications which mainly rely on their unusual physical characteristics. Among these superhard materials, diamond is of the greatest interest. Diamond is a functional material such as its extreme rigidity, favorable physical and chemical properties. It has high electron vacant-site migration rate, large band gap, high breakdown voltage and large thermal conductivity. Diamond excels all other materials in many aspects. Now, it has being applied in many fields such as industry, scientific research, national defence, medical treatment etc. As a new force, industrial diamonds boost the development of industry society.In the high-pressured high temperature indirect static pressure law synthesis diamond aspect, US, Japan, South Africa, Russia have walked front, their product is occupying the world market. The technique for the synthesis of diamond has been greatly improved due to its extensive application. In the late 1980s, the technique for the high-strength coarse diamond crystal synthesized by powdered catalyst in the belt apparatus was successfully exploited by Winter Company, Germany, which made a great breakthrough in synthesis of high grade diamond using powdered materials. This synthesizing method had many merits such as increasing the output, decreasing the consumption of raw materials and improving the crystal quality, therefore, the famous diamond companies of the world almost employed this method to synthesize high-strength coarse diamond and cornered chronically the high grade diamond market since the end of 90's. Although China is a large country of the industrial diamond, most of her products belong to the mean grade in the international diamond market. The reason for that lies in the obsolete assembly cell and dated technology .Therefore, the study of the technology for the diamond synthesized by powdered materials independently is a crux to increase competitive ability of our country in international diamond market.In order to perfect the theoretical system of the diamond synthesis and promote the development of industry of diamond in our country, I have carried on research in several following respects in this paper.Use next to the thermal assembly, we look at the different process on the impact of synthetic diamond crystals, we found that two-stage step-up process is significantly good in the diamond synthesize; improving the step press in the bottom of the V shape can be beneficial to the quality of synthesized diamond.We investigated the influence of diamond seed in the system by adding a certain amount of diamond seed. We found the crystal growth range and technology are different from the spontaneous nucleation technology. Also, we have deeply understood the V-shaped area of the diamond growth.