| Diamond is one kind of limited functional material in the region of mechanics, thermodynamics, optics, chemic and electronics. It is insulator but its thermal conductivity is better than Cu. And it can stand very high electric field. Therefore, the sufficient diamond resources will be playing the extremely vital role on future industrial development, the technical level enhancement, the whole national defense capability enhancement and so on. Compared to natural diamond , the artificial diamond crystals have the same crystal structure; high purity the artificial diamond have the same capability, even more; then that expand the using of diamond. In recent years, the synthesis technology of the many Chinese diamond manufacturers has a big enhancement and their product have high quality.The superhard characteristic of the diamond is used to the industry. The diamond tools have a broad using in cutting the more hard non-iron metal, machining non-metal materials, artesian well and so on. As the society development, the applications of diamond becomes abroad. We can produce many kinds of diamond tools.Recently, in the field of diamond synthesis, powder catalyst technique has gradually replaced the traditional slice catalyst depending on its advantages of high unit yield, low raw material consumption and good synthesis quality. Especially, with the extensive application and popularization of the large-scale cubic high pressure apparatus and indirect heating technique, the level of Chinese diamond synthesis using powder catalyst has made a great step forward in, and china is gradually stepping in the ranks of strong country on diamond synthesis.In the crystals of synthesized diamond grown from conventional metal solvent-catalysts, the shapes of crystals have cubic, cubo-octahedral and octahedral shape. Because those crystals have comparatively regular shape, the grinding tool which made in those crystals have threshing phenomenon in application. So we expect that we produce irregular crystals (for example, the strip-shape diamond crystal) so that stop from this needless wastage. In our lab, we have synthesized the strip-shape diamond crystal successfully, using the new-type iron base catalyst by the doctor Liu wanqiang. The ratio of length and diameter is between 1.5 and 2, the average granularity is about 0.5m; In order to grow the longer and higher ratio of the length and diameter, we mix the diamond crystals into the synthesized samples, continue to grow, than we call it"he method of crystal seed".First, the strip-shape industrial diamond is growth in the system of Fe70Ni30 and A(the additive of our lab design). And we study the strip-shape industrial diamond characteristic in the three different shapes of crystal seeds, and the macro-characteristic, analyze the growth mechanism, the main contents as follows:(1) We have growth the strip-shape industrial diamond successfully, in the Fe70Ni30 system with the additive A, by append three shapes of diamond crystals.(2) The granularity, ratio of length and diameter, color are different; the granularity of the strip-shape industrial diamond growth with the crystal seed of the common-shape and strip-shape are large; the impurity is much; Compared to the former, the granularity of the strip-shape industrial diamond growth with the crystal seed of 400m diamond power is small, the impurity is less; all the crystal using crystal-seed method is green.(3) The metal film has been generated in the process of the diamond crystal growth, can dissolve graphite, and translate graphite into diamond , the agglomeration phenomenon is proved to be right directly.From the knowledge of crystal growth, the condition of crystal growth is steady, the fluctuation of the factors cause the quality drop. The pressure and temperature are very important, while the mix manner is also important to the strip-shape diamond. So we study the effect of the pressure, temperature and mix manner:(1) Compared to the system with no additive A, the system with additive A is much fitter to grow the high ratio of length and diameter strip-shape industrial diamond.(2) Pressure have effect on the quality of crystal growth, when the pressure is higher than the growth pressure, they will have nuclei, in the process of growth, the growth speed is too quick, the process decline.(3) Temperature have also affect the quality of the crystal, when the temperature leans low, the impurity in the crystals is much; while the temperature leans high, the surface of crystal became to bad, cuase"over-fever".(4) The strip-shape industrial diamond crystals have been growth in the three kinds of mix manners under high temperature and high pressure.(5) The mix-manner of M+d+A+g is thick, the ratio of length and diameter is also small; the mix-manner ofã€(M+d)+T-Fe】+g is thick and long, the ratio of length and diameter is about (2-3); the mix-manner ofã€(M+d)+g】+T-Fe is thick and large, the ratio of length and diameter is small, in the 1.7~2.0; the mix-manner of (M+d)+(g+T-Fe)is thin and short, but the ratio of length and diameter is big, the value may reach 3.In the end, in order to analyze the surface characters of the diamond synthesized in the system of Fe70Ni30-C-g (diamond) with additive A more carefully, we took some SEM photographs of synthetic crystals. Its main characters as follows:(1) Compared to the two kinds of different temperature SEM photographs, we found, the surface of the low temperature have bug and growth texture, as the temperature becomes high, the surface improve, while the temperature become rather high, the quality of crystals become bad. (2) Compared to the two kinds of different pressure SEM photographs, we found, the quality of crystal which growth pressure leans low is smooth, because the growth speed is low; the quality of crystal which growth pressure leans high, the surface of crystal adhibits small crystals, affects the quality.(3) By the SEM analysis, the strip-shape industrial diamond crystals are elongated for two different manners, one along with the {100}; another along with the {111}.
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