The Influence Of The Nitrogen Impurity Against The Nature Of Manmade Diamond

It's well-known that diamond has various good natures, such as the highest rigidity, the highest conductance of heat, the smallest compression ratio, the widest light-wave, the fastest velocity of sound, the nature against hard-acid and alkali as well as eradiation, attacking the high voltage, high loading transference rate and so on, so it is used widely in industry, science and technology, national defense, medical treatment and other fields. For example, the diamond is used in the mechanism process of high rigidity material in a large scale. It can be used as rigid tool for machining, laser ware for semiconductor and the coolant of laser arms, the window material for the division of infrared ray, pressing head for the diamond on the pressing machine and so on.Among the various natures of the diamond, the nature against pressure is one of the important symbols of weighing the quality of the diamond. In 1954 the American G.E. Company composed the first manmade diamond and after that the technology of making manmade diamond developed very fast. Currently the scientists are studying the way of using manmade methods to adjust the quantity of nitrogen impurity of the diamond and its state of being to produce high intensity Ia type of diamond. GE Company reported that they have already been able to do heat treatment of Ib type diamond under 2000℃and 60Kb for several hours to make the detracted nitrogen get together into flakes state and turn into Ia type diamond finally. Other reports said that the state of nitrogen's existence is something related to the composing condition. But in the field of manmade diamond's producing, the techniques of composing of the diamond and the related technical information are always kept secret and we must grope many technical indexes in this field. Therefore the purpose of the thesis is to do the primary discussion of increasing the content of nitrogen of the diamond crystal so as to improve the intension of the diamond.In order to compose the diamond with high quality nitrogen, we should firstly take the way of accelerant nitriding to add the atom-state nitrogen into the accelerant of the raw and processed materials. After get four different transects of gold phase pictures of the nitriding accelerant unwashed with acid and washed with acid, use nitriding pure accelerant to compose four magnetism resonance spectrum line and the content of containing nitrogen impurity gained by ESR spectrum and absorbing spectrum method and the total content of nitrogen, including ESR spectrum width and the value of g. Secondly we also adopted composed assembly which was added a little nitrideC(ONH2)2 to add the atom-state nitrogen to compose the diamond with higher content of nitrogen. After the analysis we got a conclusion that adding the atom-state nitrogen into the raw and processed materials can make the nitrogen impurity of paramagnetism of the diamond increase; when the content of paramagnetism nitrogen impurity is under 1019/cm3 , the influence of diamond against pressure is not obvious and when the content of paramagnetism nitrogen impurity reaches 1020/cm3 , the color of the diamond will turn from yellow into green and turn crisp obviously and the nature against pressure will descend. The reason is that after add a little nitride into composing pieces and use the way of accelerant nitriding to compose the diamond contained high content of nitrogen , the nitrogen exists in the form of paramagnetism ( state of separation)and thus reduces the nature against pressure of the diamond.Because the result mentioned above is not ideal, we adopted special methods to add molecule-state nitrogen into raw and processed materials'accelerant, too. When we gain the ESR spectrum under the situation of adding molecule-state nitrogen or without molecule-state nitrogen, we should use ESR spectrum and absorbing spectrum method to obtain the nature against pressure, the total content of paramagnetism nitrogen, the total content of nitrogen and the spectrum of ESR. After we analyze, we got the final conclusion that adding the molecule-state nitrogen into the composed materials will make the nitrogen impurity of the diamond increase; the nitrogen content of the paramagnetism reduces and the total nitrogen content is 5.5 times of the paramagnetism nitrogen; the nature against pressure is improved. The reason is when the nitrogen atom group of flake state of the diamond exists, besides the formed diamond covalent bond, the combining strength will be strong and the intensity will also be strengthened. To sum up, we will realize by the work mentioned above...