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Discussion on Calculation Method of Material Ratio of Mixed
from 101 China Grinding
Burden for Brown Corundum Smelting (II)
Text/Hu Yong Guizhou Dazhong Seventh Grinding Wheel Co., Ltd
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2.Discussion of problems and matters needing attention in using traditional methods
2.1 The existing Problems
2.1.1 There is ambiguity in the understanding of the concept of ferrosilicon ratio
In the traditional calculation formula (2) and (4) for the ratio calculation of mixed charge materials for brown corundum smelting, K is specified as "iron-silicon ratio of ferrosilicon", which is defined as the ratio of iron percentage content and silicon percentage content of ferrosilicon. Due to the diversification of the silica reduction reaction pathways in the mixed charge during the smelting process of brown corundum, except for the removal of a part of the reduction to elemental silicon and the generation of ferrosilicon, the rest will either generate SiO and other gases to be removed, or a small amount of silicon The residual in the form of silicon has not been reduced, resulting in the inconsistency between the iron-silicon ratio in the actual ferrosilicon and the "iron-silicon ratio" used in the calculation of the ratio of the mixed charge and the batching operation, the ironsilicon ratio in actual ferrosilicon is the real iron-silicon ratio, and the "iron-silicon ratio in ferrosilicon" used in the calculation of mixed charge ratio and batching operation is not the real iron-silicon ratio in ferrosilicon, so what K wants to express is not the iron-silicon ratio in ferrosilicon, but a parameter specified to meet the requirements of certain material ratio, this parameter can be expressed in the conceptual term "batching iron-silicon ratio", which is defined as the ratio of the percentage of iron to the percentage of silicon in the mixed charge. It can be seen that the "ingredient iron-silicon ratio" and the iron-silicon ratio of ferrosilicon are two completely different concepts. The so-called "iron-silicon ratio of ferrosilicon" in the traditional method calculation formula is actually the "ingredient iron-silicon ratio". The understanding and understanding of the meaning are different, resulting in ambiguity about the concept of ferrosilicon ratio.
2.1.2 The ratio range of ferrosilicon in ingredients is different, with high and low values
It is clear that after K in the calculation formulas (2) and (4) is the ratio of iron to silicon, how to take the value of the ratio of iron to silicon is the first problem that must be solved. The value range of the ingredient iron-silicon ratio is different from the value range of the iron-silicon ratio of ferrosilicon, but the value of the ingredient iron-silicon ratio is obviously closely related to the iron-silicon ratio of ferrosilicon. Its purpose is mainly to ensure that the iron-silicon ratio of ferrosilicon is within an appropriate range (4.5~6.5) to meet the needs of promoting impurity sedimentation and separation and promoting impurity reduction reaction, and to meet the needs of ensuring the magnetic properties of ferrosilicon, at the same time, the economic use of iron additives needs to be considered.
According to the recommendation of relevant data, the appropriate value range of iron-silicon ratio in ferrosilicon is 4.5~6.5. Is it the iron-silicon ratio in ferrosilicon or the iron-silicon ratio in ingredients? Due to the ambiguity in the understanding of the concept of ferrosilicon ratio, some directly regard the ferrosilicon ratio in ferrosilicon as the ingredient iron-silicon ratio, which causes the iron-silicon ratio in the actual ferrosilicon to be higher than 4.5~6.5, generally reaching 6~8 or even higher; some believe that this requirement is the iron-silicon ratio in the actual ferrosilicon, as long as it can ensure that the iron-silicon ratio in the actual ferilicon is within the specified range (4.5~6.5), in addition, iron additives are used for different purposes and smelting equipment are different, so the ratio of iron to silicon in ingredients is often lower, and its value is mostly less than 5.0. In other words, due to the different understanding and understanding of the concept of ferrosilicon ratio, the batching iron-silicon ratio range used in the material ratio calculation formula is different, and the value is high and low.
2.1.3 There is no specific quantification to reflect the reduction of aluminum oxide and its effect on the material ratio
In the traditional method, some deterministic influencing factors, when discussing their influence on the material ratio, are treated as random influencing factors together with all other random influencing factors, and are not specifically quantified and reflected in the material ratio calculation formula.
Specifically, the traditional method of material ratio calculation formula only considers the reduction reaction of ferric oxide, silicon dioxide, and titanium dioxide. In fact, the reduction of aluminum oxide is inevitable, and the reduction of aluminum oxide is inevitable. Has an impact. Especially when the content of titanium dioxide in the raw material is high, the reduction amount of aluminum oxide is greater, and the effect of aluminum oxide reduction on the material ratio cannot be ignored.
Since the reduction reaction formula reflecting the physical and chemical principles based on the traditional method calculation formula is not comprehensive, it cannot accurately reflect the actual situation of the brown corundum smelting process. In the calculation formula of the mixed charge material ratio, there is no special quantitative reflection of the aluminum oxide The reduction and its influence on the material ratio, so the accuracy of the material ratio will inevitably be affected.
2.1.4 The degree of impurity reduction adopts a fixed value, which cannot accurately reflect the actual situation of the smelting process
For brown corundum smelting, it is necessary to reduce and remove impurities such as ferric oxide, silica, and titanium dioxide in the mixed charge in order to obtain brown corundum melt with chemical composition that meets the requirements. Whether it is from the chemical balance theory or from the practice of brown corundum smelting, all kinds of impurities cannot be completely reduced and removed, and a certain amount will always remain. Therefore, for materials of different quality, the degree of reduction of these impurities is It changes, not a fixed value; even if the same raw material and the same material ratio are used, due to the complexity and non-repeatability of the smelting process, the degree of reduction of various impurities is constantly changing, it will not be consistent; while the traditional method calculates the degree of reduction of impurities in the formula is a fixed value, which obviously cannot accurately reflect the actual situation of the brown corundum smelting process.
2.1.5 There is no specific quantification to reflect the effect of silicon and ferric oxide in iron additives on the material ratio
The silicon element and ferric oxide in iron additives are always inevitable. Due to the decrease in the quality of iron additives that can be obtained, one is that oxidation or doping increases the content of ferric oxide, and the other is that there is a certain amount of silicon element, which should be regarded as a deterministic influencing factor. The influence of the ratio of reducing agent and the ratio of iron additives cannot be ignored, and needs to be reflected in the material ratio calculation formula, but the traditional method calculation formula does not specifically quantify this.
2.1.6 The selection range of carbonaceous reducing agent ratio adjustment coefficient is wide
For the adjustment of the theoretical ratio of carbonaceous reducing agent, the specified "carbonaceous reducing agent ratio adjustment coefficient" is a comprehensive consideration of the accuracy of the theoretical ratio calculation formula (no distinction between deterministic influencing factors and random influencing factors) And the combined effect of various factors at the level of smelting practice (random influencing factors), an empirical coefficient that adjusts the theoretical ratio calculation formula and generally stipulates, the physical meaning is general, the selection range is wide, and its accurate value needs to be determined through smelting practice experience, specific selection and timely adjustment. The reason for this problem is that the traditional method does not distinguish the influencing factors of the accuracy of the theoretical ratio calculation formula according to the random influencing factors and the deterministic influencing factors according to the nature and law of action of the influencing factors, and does not distinguish the influencing factors of the accuracy of the theoretical ratio calculation formula from the influencing factors at the level of smelting practice, and adjust the theoretical ratio of carbon reducing agent according to their respective laws of action.
2.2 The Matters needing attention
2.2.1 The applicable requirements of the calculation formula for the chemical composition of bauxite
When the titanium dioxide content in the main raw material bauxite is low (for example, it is lower than 2.5%), the theoretical ratio calculation formula of carbonaceous reducing agent is not applicable, and the raw material combination needs to be readjusted, otherwise it will not only not be guaranteed that the titanium dioxide content in brown corundum is within the range of 1.5% ~ 3.8%, and the aluminum oxide content will also be high; the titanium dioxide content cannot be too high (for example, greater than 7.5%), otherwise the theoretical ratio calculation formula of carbonaceous reducing agent is also not applicable, it is also necessary to readjust the combination of raw materials, otherwise it cannot be guaranteed that the content of titanium dioxide in brown corundum is in the range of 1.5% ~ 3.8%, and the content of aluminum oxide is often lower than 94.5%.
2.2.2 The chemical composition of brown corundum is not a point value but a range value
According to the calculation formula of the traditional method, the expected chemical composition of brown corundum is not a point value but a range value, and there is no fixed target value. Therefore, the same bauxite or bauxite of different quality, especially bauxite with different titanium dioxide, is used to prepare mixed furnace materials according to the calculated material ratio. Due to the complexity and non-repeatability of the smelting process, the reduction degree of various impurities will not remain the same. The chemical composition of brown corundum produced by different furnaces is different, there is a certain range of changes, and the technical conditions of brown corundum products are stipulated, I .e. aluminum oxide content 94.5% ~ 97.5% and titanium dioxide content 1.5% ~ 3.8%. Therefore, when the chemical composition of brown corundum meets the technical conditions, its specific chemical composition is different, resulting in different physical and chemical indexes and technical properties, and the product quality and use are not exactly the same.
Conversely, because the technical conditions of brown corundum products stipulate that the chemical composition has a certain range of changes, the same quality bauxite can be used, and only the adjustment coefficient of the carbonaceous reducing agent in the calculation formula needs to be changed, thereby changing the degree of reduction of impurities such as titanium dioxide, Changing the material ratio and adjusting in front of the furnace can obtain brown corundum that meets the requirements with different specific chemical compositions of brown corundum, but whose chemical composition is within the scope specified by the technical conditions. Further requirements, in order to make the chemical composition of brown corundum basically consistent and have a fixed target value, it is necessary to change the adjustment coefficient of the carbonaceous reducing agent ratio in the calculation formula, adjust the material ratio, and supplement it with furnace adjustment, Control can be achieved.
2.2.3 The quality of raw materials shows a downward trend
With the development of social economy and the progress of science and technology, the demand for product market and raw materials is increasing, and the market demand for bauxite, carbonaceous reducing agent and iron additive is also increasing. Bauxite and carbonaceous reducing agents are non-renewable resources, especially high-quality bauxite resources. With the continuous exploitation and use, their natural reserves are becoming less and less, even close to exhaustion. As a result of market competition, the quality of bauxite used in brown corundum smelting is getting worse and worse. The advancement of casting technology has greatly developed precision casting and no-allowance casting. The machining allowance of castings is very small or even can be used directly without processing, resulting in the output ratio and output of cast iron chips and cast steel chips. Decline, but the actual market demand is constantly increasing. This contradiction between supply and demand is the inevitable result of technological progress and social and economic development, which directly leads to the shortage of iron additives for brown corundum smelting, the decline in quality is also an indisputable fact. The result of the decline in the quality of raw materials exceeds the standard to a certain extent, which will inevitably affect the accuracy of the material ratio calculation formula, and then affect the accuracy of the material ratio.
2.2.4 The quality of bauxite decreases, which requires higher accuracy of material ratio
The decline in the quality of bauxite is manifested in the practice of brown corundum smelting, that is, the furnace condition is unstable, the operation in front of the furnace is difficult, the operating conditions are deteriorated, the material flying and the combustion loss increases, the material ratio in the furnace changes, and the quality in front of the furnace is adjusted Frequent and large, even leading to safety accidents, and various technical and economic indicators are not ideal. These adverse effects will further deteriorate when the material ratio is inaccurate, thus reducing the quality of bauxite and requiring higher accuracy of the material ratio.
2.2.5 The choice of iron-silicon ratio is affected by many factors
Due to the different understanding and understanding of the concept of iron-silicon ratio, as well as the main purpose pursued in the smelting process of brown corundum and the different uses of brown corundum products, it promotes impurity sedimentation and separation, promotes impurity reduction reaction, and ensures the magnetic properties of ferrosilicon The degree of attention is different, and it is affected by the economic use of iron additives, which affects the choice of iron-silicon ratio.
In addition to the silicon element affecting the magnetic properties of ferrosilicon, other component metal elements such as aluminum and titanium in ferrosilicon content is high, its influence can not be ignored, thus affecting the choice of iron-silicon ratio.
2.2.6 Pre-furnace adjustment is an essential process operation
For carbonaceous reducing agent, since the "carbonaceous reducing agent ratio adjustment coefficient" in the calculation formula for adjusting the ratio is a range value with a certain degree of uncertainty, the accuracy of adjusting the ratio of carbonaceous reducing agent will be affected, and the pre-furnace adjustment of the smelting site should be considered as appropriate to make up for its shortcomings. Pre-furnace adjustment is an essential process. Considering the amount of carbonaceous reducing agent ratio after the pre-furnace adjustment amount, it is the actual ratio of carbonaceous reducing agent, but as long as the carbon reducing agent ratio adjustment coefficient is properly taken, the carbon reducing agent adjustment ratio can be directly used as the actual ratio amount.
For iron additives, generally do not consider the pre-furnace adjustment amount, the iron additive adjustment ratio or theoretical ratio directly as the actual ratio.
3.New Method for Calculating Material Ratio of Mixed Burden for Brown Corundum Smelting
As mentioned above, through the research and analysis of the traditional method of calculating the material ratio of the mixed charge for brown corundum smelting, as well as the discussion of the problems and matters needing attention in the use of the traditional method, on this basis, this paper proposes a "new method for calculating the material ratio of the mixed charge for brown corundum smelting" with a wider range of raw material quality ". In the new method, the material ratio also includes the theoretical ratio, the adjustment ratio and the actual ratio; the calculation formula also includes the theoretical ratio calculation formula and the adjustment ratio calculation formula.
3.1 Calculation Formula of theory Ratio
In line with the principle of "improving the theoretical model to improve the accuracy of material ratio", in the derivation of the new method, the factors affecting the accuracy of the theoretical ratio calculation formula are overcome and improved. The factors influencing the accuracy of the theoretical ratio calculation formula are distinguished according to random influencing factors and deterministic influencing factors, and the deterministic factors that affect the accuracy of the theoretical ratio calculation formula are specifically quantified into the calculation formula as much as possible.
In the new method, the derivation of the theoretical ratio calculation formula takes into account the actual situation of the brown corundum smelting process as follows, and makes provisions, which is also the condition for the establishment of the theoretical ratio calculation formula of the new method:
(1) Target value of chemical composition of brown corundum: aluminum oxide content 95.0% ~ 96.0%, titanium dioxide content 2.5% ~ 3.5%, which is based on the general applicability of brown corundum and specified chemical composition; Other provisions can also be made according to smelting purpose, use and economic considerations;
(2) with the different content of aluminum oxide in bauxite, the consumption of bauxite for smelting 1 ton of brown corundum shall not exceed 1.4~1.5 tons, generally 1.1~1.3 tons;
(3) There is still a small amount of silica remaining in bauxite that has not been reduced. The degree of reduction is determined by the residual 0.5% of silica in the reduced bauxite, and the carbon distribution coefficient is determined by the formation of elemental silicon from silica;
(4) Iron trioxide is based on the formation of elemental iron to determine the carbon distribution coefficient, the degree of reduction in 100%;
(5) The carbon distribution coefficient of titanium dioxide in bauxite is determined by the formation of elemental titanium, and the degree of reduction is determined by the residual 2.3% ~ 3.0% titanium dioxide in the reduced bauxite, which can control the content of titanium dioxide in brown corundum to 2.3% ~ 3.5%;
(6) When the titanium dioxide in bauxite is less than 2.3%, it is necessary to take measures to increase titanium dioxide in bauxite; titanium dioxide is preferably lower than 5.5%, and when it exceeds 5.5%, it is necessary to take measures to increase aluminum oxide and reduce titanium dioxide in bauxite;
(7) Since the reduction difficulty of aluminum oxide and titanium oxide is close, aluminum oxide will inevitably be reduced when titanium dioxide is reduced, so a certain amount of carbonaceous reducing agent needs to be consumed. According to the experience learned from the practice of brown corundum smelting, it can be set to reduce 1 mol of titanium trioxide, and accordingly there will be 1 mol of aluminum trioxide reduction; equivalent to 2 mol of titanium dioxide reduction, corresponding to 1 mol of aluminum trioxide; converted into a weight ratio, if 1kg of titanium dioxide is reduced, 0.64kg of aluminum trioxide will be reduced. Based on this, the amount of aluminum oxide reduction in bauxite is calculated. A large part of these reduced aluminum oxide enters the smelting flue gas dust. A small part enters ferrosilicon, which will adversely affect the magnetic properties of ferrosilicon. This situation is mainly when the aluminum oxide content in brown corundum exceeds 96.5%, the influence is relatively obvious;
(8) There is a small amount of silicon in the iron additive and a certain amount of ferric oxide. It is necessary to consider adding another part of the iron additive and carbonaceous reducing agent;
(9) In the carbonaceous reducing agent, the amount of silica, ferric oxide and titanium dioxide brought in by ash is very small, and its influence on the material ratio is negligible;
(10) In bauxite, the relevant impurity components and their content involved in the calculation formula should meet the technical requirements. There are no other impurity components or their content is very small, which does not affect the realization of the chemical composition of brown corundum;
(11) In the process of brown corundum smelting, in addition to the reduction reaction of the relevant impurity components involved in the calculation formula, the reduction reaction of other impurity components can be ignored;
(12) Scientifically determine the value of the iron-silicon ratio. The purpose is to meet the needs of promoting impurity sedimentation and separation and promoting impurity reduction reaction, to meet the needs of ensuring the magnetic properties of ferrosilicon, and to consider the economical use of iron additives;
(13) Except that silicon elements affect the magnetic properties of ferrosilicon, other component metal elements do not affect, or the content of ferrosilicon is very small, and its influence is negligible.
According to the above regulations, a new method for calculating the ratio of mixed charge materials for brown corundum smelting is used. Based on 1000kg bauxite, the theoretical ratio (kg) of carbon reducing agent and iron additive is calculated, and the theoretical ratio is obtained accordingly. The new method of theoretical ratio calculation formula is derived as follows:
In the calculation formulas (5) and (6): K is the ratio of iron to silicon, the theoretical ratio of GC carbonaceous reducing agent (kg), GFe is the theoretical ratio of iron additive (kg), TFe2O3% is the percentage content of ferric oxide in iron additive, and Kf is the supplementary adjustment coefficient of the proportion of iron additive; X% is assumed to be the percentage content of titanium dioxide remaining in reduced bauxite, in the range of 2.3% ~ 3.0%, it is selected according to the needs of the product, generally 2.3%.
It should be emphasized that the value of the ingredient ironsilicon ratio K needs to consider the influence of two factors, namely:
(1) In bauxite, except for a part of silicon dioxide reduced to elemental silicon and then generated ferrosilicon removed, the rest is either removed by generating SiO and other gases, or a small amount of residual silicon dioxide has not been reduced, which can reduce a certain amount of iron additives under the condition of ensuring the magnetic properties of ferrosilicon, which can be determined by reducing the value of the iron-silicon ratio of ingredients;
(2) When the content of aluminum oxide in brown corundum is greater than 96.5% and the content of titanium dioxide is less than 2.0%, the magnetic properties of ferrosilicon will decrease. It is necessary to increase the ratio of iron to silicon in the ingredients, and then increase the ratio of iron additives.
The formula for calculating the additional adjustment factor Kf for the proportion of iron additives is:
In formula (7): K' is the supplementary iron-silicon ratio, which is defined as the iron-silicon ratio of ferrosilicon when a certain amount of iron additive is added to the silicon element content in the iron additive to generate "assuming ferrosilicon", so as to ensure the main basis for the magnetic performance of "assuming ferrosilicon", and its value range is 4.5~6.5. Kf is mainly affected by the iron content, silicon content and the ratio of added iron to silicon. Si% is the percentage of silicon in the iron additive, and TFe% is the percentage of total iron in the iron additive.
In the new method, the theoretical ratio calculation formula is more accurate than the traditional method calculation formula, because of the more comprehensive consideration of deterministic factors, so it can more accurately reflect the actual situation of the brown corundum smelting process, and its accuracy is higher.
3.2 Calculation Formula of adjustment Ratio
The same as the traditional method, because the understanding of the deterministic influencing factors and the law of action that affect the accuracy of the theoretical ratio calculation formula is not necessarily comprehensive, the random influencing factors that affect the accuracy of the theoretical ratio calculation formula is no't necessarily comprehensive, the random influencing factors that affect the accuracy of the theoretical ratio calculation formula still exist, and the accuracy of the theoretical ratio calculation formula of the new method is bound to be affected. It is determined by the accuracy of the theoretical ratio calculation formula, and the random influencing factors at the level of smelting practice still exist and exert influence. The accuracy of the theoretical ratio of mixed charge calculated according to the new method will also be affected, so it cannot be directly used. It needs to be adjusted based on the theoretical ratio calculation formula to obtain a more accurate adjustment ratio calculation formula, and then calculate the adjustment ratio before it can be used in smelting practice. The adjustment ratio is more accurate than the theoretical ratio.
For the adjustment of the theoretical ratio of carbon reducing agent, in the new method, the influence factors of the accuracy of the theoretical ratio calculation formula and the influence factors of the theoretical ratio accuracy of the smelting practice level are adjusted respectively. The adjustment method is to consider the overall role and laws of the two types of influencing factors, and specify an empirical coefficient respectively, that is, the theoretical model adjustment coefficient KC1 "in the factors affecting the accuracy of the theoretical ratio calculation formula, and the randomness of the smelting practice level The influencing factors stipulate a" carbon reducing agent ratio adjustment coefficient KC2 ", and the product of the two is the" carbon reducing agent ratio adjustment coefficient KC ", according to the calculation of carbonaceous reducing agent adjustment ratio.
The calculation of the amount of carbonaceous reducing agent adjustment ratio is to multiply the calculation formula (5) by the carbonaceous reducing agent ratio adjustment coefficient KC, that is, according to the calculation formula (8): recommended to be selected and adjusted in time within the range of 1.1~1.2. Generally, the average value is 1.15.
Compared with the traditional method theoretical ratio calculation formula (1), the new method theoretical ratio calculation formula (5) more accurately reflects the actual situation of the brown corundum smelting process, and the accuracy of the new calculation method theoretical ratio calculation formula has been improved to a certain extent. Therefore, the value range of the carbon reducing agent ratio adjustment coefficient KC is relatively narrow, generally between 1.1 and 1.2.
For iron additives, whether it is affecting the accuracy of the theoretical ratio calculation formula, or the influence of the smelting practice on the accuracy of the theoretical ratio of iron additives, there are not many influencing factors, and the degree of influence
It is also small and negligible. Therefore, in the new method, the adjustment of the ratio of iron additives is equivalent to the theoretical ratio, just directly based on the percentage of silica and ferric oxide in bauxite, and the percentage content of silicon in the iron additive and the percentage content of total iron are equivalent to the calculation formula (6), which can be calculated according to the formula (7) and (9).
In the calculation formula (8): G'C is the adjusted ratio of carbon reducing agent (kg); The adjustment coefficient KC1 of the carbonaceous reducing agent ratio model is 0.9~1.0; the specific value of the adjustment coefficient KC2 of the carbonaceous reducing agent ratio operation is mainly due to different smelting equipment (including furnace type and transformer power), different operation processes (submerged arc operation or open arc operation and different electrical parameters, etc.), The variety and quality of carbonaceous reducing agent, the quality of bauxite, especially the content of titanium dioxide, the quality of iron filings additive, the target value of brown corundum chemical composition, etc., need to be determined through smelting practice; the value of KC2 is
Dr. Yuan talks about diamonds: the macro and micro structure of diamonds
Text/Yuan Zhizhong
The article was first published on the official account: Diamond Watch
Using the synchrotron radiation device of the Beijing Electron Positron Collider, the electron beam is first accelerated to a high-energy electron beam current with a linear accelerator, and a high-speed cyclic motion is performed in a storage ring with a circumference of 240.4 meters, and the speed reaches near the speed of light. Synchrotron radiation X-ray is introduced to the outer test station along the tangent direction. The diamond sample is located between the light source and the negative. The synchrotron white light incident ray is horizontally injected into the sample, the film enters the ray vertically, and the white light morphology can obtain the diffraction of multiple crystal plane groups in a few seconds. However, synchrotron radiation equipment cannot be easily used. A small X-ray machine can also be used to irradiate the sample, but it takes tens of minutes to be sensitive. The diffraction of multiple crystal plane groups is also obtained on the negative. The diffraction of each crystal plane group is arranged in an orderly manner in the direction of the main crystal plane, and the degree of symmetry of the arrangement shows the degree of difference between the angle of the facet and the main crystal plane. Jewelry does not need to consider the direction of the main crystal plane, but it is often necessary to determine the direction of the main crystal plane, for example, the (100) surface is a square structure, the (111) surface is a triangular/hexagonal structure, and the (110) surface is an oval structure. The following figure:
▲The picture on the left shows the diffraction of multiple groups of crystal planes in the direction of the main crystal plane (110) of natural brown diamond. At the correct angle of symmetrical elliptical arrangement, after the growth of brown diamond is completed, it is under great pressure under the ground. The two enlarged figures on the right show that the two crystal planes are squeezed to cause plastic deformation and broken.
Microstructure of Diamonds
Using a transmission electron microscope, diamonds can be magnified tens to millions of times, and carbon atoms can be seen. It is very difficult to make a sample. First, the diamond is ground to a 10-30 micron sheet, and then it is thinned by argon ions to penetrate the center, and the surrounding area is gradually thicker to a thickness of 2000 Å. You can see the diamond sheet in the transmission electron microscope. Microstructure defects, atomic lattice image and atomic image.
▲ Under the transmission electron microscope of CVDcultivated diamonds, black graphite inclusions, isofing patterns and dislocations can be seen. The transmission electron microscope (TEM) studies the structure of high temperature and high pressure (HPHT) diamond is not perfect, and there are dislocation loops and dislocation couples. It is due to the supersaturated vacancy in diamond and the existence of internal stress and inclusions.
Characteristics of transmission electron microscope:
To observe the very tiny impurities in the diamond, it is necessary to reduce the diamond to a thickness of several microns, and use a transmission electron microscope to increase it by thousands to tens of thousands to millions of times. TECNAI F30 field emission transmission electron microscope (FEI) was used to test cultured diamonds at 300KV. The results shown in the following figure show that when the growth rate of CVD cultivated diamond is fast, it is easy to have carbon atoms that are not converted into SP3 structure diamond, and the impurity state of SP1, SP2 carbon or graphite remains in the grown CVD cultivated diamond. Because the body is active and small, it can only be enlarged and observed with TEM of thousands to ten thousand times, and black graphite inclusions, equal tilting and dislocation can be seen.
▲ Equal Tilting and Dislocation Couples of HPHT Synthetic Diamond with Radiation Color Changed Dark Red
