Colored momulberry diamond and preparation method thereof

Abstract

The invention provides colored Momulberry diamond and a preparation method thereof, and particularly relates to the field of colored Momulberry diamond manufacturing. The colored momulberry diamond comprises a body material and an auxiliary material, the body material is a silicon carbide crystal with microtubes, the density of the microtubes in the silicon carbide crystal is 1-500 ea / cm < 2 >, the auxiliary material is a colored substance, and the microtubes of the silicon carbide crystal are filled with the colored substance. According to the invention, the silicon carbide crystal with the micro-tube structure is used as a main body, and the colored substance is used as an auxiliary material and is filled in the micro-tube, so that the color is increased, and the low-cost and multi-colored Momulberry diamond is obtained.

Description

Technical Field

[0001] The present invention relates to the field of colored moissanite manufacturing, and in particular to a colored moissanite and a preparation method thereof. Background Art

[0002] Moissanite, also known as silicon carbide, possesses advantages such as a high melting point, high hardness, corrosion and radiation resistance, and excellent thermal stability. Furthermore, moissanite possesses a high refractive index (2.65-2.69), which imparts a strong luster and brightness. Its dispersion value is approximately 2.4 times that of diamond, producing striking, vibrant color effects under illumination. Therefore, moissanite is considered an economical alternative to diamond.

[0003] High-purity moissanite is colorless and transparent. Different colors can be obtained through deliberate doping. For example, by doping with elements such as Al, V, or P, blue, yellow, or green moissanite can be produced. Currently, the mainstream preparation method for moissanite is physical vapor transport (PVT). However, because this preparation method cannot control the release rate of the dopant, the resulting moissanite has poor color uniformity. In the early stages of growth, more dopant is released, resulting in a darker color near the seed crystal. By the end of growth, the dopant is almost completely released, and the color of the moissanite is very light. Obtaining a uniform color throughout the entire piece of moissanite is extremely difficult. Furthermore, the colors currently achievable through doping are limited, and the color development mechanisms of colors such as red, pink, and purple have not yet been clearly explored.

[0004] Currently, most colored moissanite diamonds on the market rely on coatings to improve their color, but this approach is far less durable than coloring through doping. Some proposals for color enhancement include heat treatment and irradiation, but these methods often only fine-tune the inherent brightness or depth of the color without adding other colors.

[0005] Therefore, it is necessary to provide a colored moissanite and a preparation method thereof to improve the above-mentioned problems. Summary of the Invention

[0006] The present invention provides a colored moissanite and a preparation method thereof, so as to solve the technical problems of uncontrollable and short-lasting color of moissanite.

[0007] The present invention provides a colored moissanite, which comprises a main material and an auxiliary material, wherein the main material is a transparent silicon carbide crystal with microtubes, and the microtube density in the silicon carbide crystal is 1 to 500 ea / cm 2 , the auxiliary material is a colored substance, and the colored substance is filled in the microtubes of the silicon carbide crystal.

[0008] In one embodiment of the present invention, the diameter of the microtube is 5-300 μm.

[0009] In one embodiment of the present invention, the volume of the microtubes accounts for 0.5% to 45% of the volume of the colored moissanite.

[0010] In one embodiment of the present invention, the bulk material is 4H or 6H silicon carbide crystal.

[0011] In one embodiment of the present invention, the auxiliary material is an organic colorant, and the solid-state refractive index of the organic colorant is greater than or equal to 1.6.

[0012] The present invention also provides a method for preparing colored moissanite, which comprises at least the following steps:

[0013] Preparation of silicon carbide crystals with microtubes;

[0014] Colored substances are filled into the microtubes of the silicon carbide crystals to produce colored moissanite.

[0015] In one embodiment of the present invention, the step of preparing the silicon carbide crystal with microtubes includes:

[0016] Putting silicon carbide powder into a crucible, doping the silicon carbide powder with a material containing a microtube-inducing element, and then installing a seed crystal cover with a seed crystal fixed thereon on the top of the crucible;

[0017] Place the assembled crucible into a furnace, evacuate the furnace to 0.01 mbar, and heat it to 1200-1400°C for 10-15 hours. Adjust the pressure in the furnace to 300-600 mbar, and slowly heat it to 2250-2350°C over 30 hours. Then, reduce the pressure in the furnace to 0.6-1.2 mbar over 1 hour, and raise the temperature to 2268-2368°C.

[0018] Lower the temperature to 2250-2300°C over 150 h and increase the furnace pressure to 300-500 mbar;

[0019] The mixture was cooled to room temperature and inflated to atmospheric pressure to obtain a silicon carbide crystal with a microtubular structure.

[0020] In one embodiment of the present invention, the micropipe-inducing element includes one or more of silicon, beryllium, and cerium; and the doping amount of the material containing the micropipe-inducing element accounts for 0.5% to 1% of the silicon carbide powder.

[0021] In one embodiment of the present invention, the step of filling the microtubes of the silicon carbide crystal with a colored substance includes:

[0022] Pre-treating the silicon carbide crystal so that the microtubes with closed ends form microtube channels;

[0023] Dispersing a polymer having a refractive index greater than or equal to 1.6 in an organic solvent, and adding a coloring substance to prepare a liquid organic colorant;

[0024] Injecting the liquid organic colorant into the micro-tube channel of the silicon carbide crystal under the action of pressure difference or surface tension;

[0025] The liquid organic colorant in the microtube channel is solidified.

[0026] In one embodiment of the present invention, the microtube density of the seed crystal is 0.1 to 1000 ea / cm 2 , and the radial deviation angle

[0001] is 0°~8°.

[0027] The present invention provides a beneficial effect: The colored moissanite provided by the present invention comprises a silicon carbide crystal with numerous microtubes as its main structure. A colored substance is added as an auxiliary material within the microtubes to enhance the color of the moissanite. The color of the moissanite changes according to the color of the added colored substance, thus achieving color controllability.

[0028] The colored moissanite of the present invention is prepared by doping the raw material with a microtubule-inducing element and adjusting the process to produce silicon carbide crystals with a large number of microtubules. A liquid organic colorant is then added and injected into the microtubules using pressure differentials or surface tension. The liquid organic colorant is then cured by temperature changes or ultraviolet light to produce moissanite of various colors. By combining microtubule channels with the colorant, the present invention achieves controllable coloring of moissanite, resulting in a simple process and stable coloring effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be derived from these drawings without inventive effort.

[0030] In the attached figure:

[0031] Figure 1 This is a flow chart for preparing colored moissanite provided in one embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of a crucible charging according to one embodiment of the present invention;

[0033] Figure 3 A flow chart of preparing a silicon carbide crystal with a microtube structure provided in one embodiment of the present invention;

[0034] Figure 4 This is a diagram showing the successful induction effect of 0° seed crystal microtubes provided in one embodiment of the present invention;

[0035] Figure 5 A flow chart of colored substance filling provided in one embodiment of the present invention;

[0036] Figure 6 A schematic structural diagram of a microtubule channel and its inner wall provided in one embodiment of the present invention;

[0037] Figure 7 This is a schematic structural diagram of a liquid organic colorant filling process provided in one embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the structure inside the microtube when the contact angle between the liquid organic colorant and the silicon carbide crystal provided in one embodiment of the present invention is less than 90°;

[0039] Figure 9 This is a schematic diagram of filling when the contact angle between the liquid organic colorant and the silicon carbide crystal is less than 90° provided in one embodiment of the present invention;

[0040] Figure 10 This is a color distribution diagram of colored moissanite in Example 1 of the present invention;

[0041] Figure 11 This is a color distribution diagram of colored moissanite in Example 2 of the present invention;

[0042] Figure 12 Schematic diagram of seed crystal deflection angle and microtube development provided in Comparative Example 1;

[0043] Figure 13 A schematic diagram of the structure provided for Comparative Example 1 in which the microtubule ratio is less than 0.5%;

[0044] Figure 14 Schematic diagram of the color distribution of moissanite prepared by doping in Comparative Example 1.

[0045] The reference numerals are as follows:

[0046] 100. Crucible; 110. Seed crystal cover; 120. Seed crystal; 130. Silicon carbide powder; 131. First crucible; 132. Second crucible; 200. Chamber; 210. Air inlet; 220. Air outlet; 230. Liquid organic colorant; 240. Silicon carbide crystal; 241. Microtube channel; 250. Residual liquid organic colorant. DETAILED DESCRIPTION

[0047] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments. The details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. The following embodiments and features therein may be combined with one another without conflict.

[0048] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The drawings only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0049] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the embodiments of the present invention.

[0050] The present invention provides a colored moissanite and a preparation method thereof. Silicon carbide crystals containing a large number of microtubes are used as the main structure. Colored substances are used to fill the microtubes in the silicon carbide crystals to make them appear colored, thereby increasing the color of the moissanite, thereby realizing colored moissanite with adjustable color and strong ornamental value.

[0051] The colored moissanite provided by the present invention comprises a base material and an auxiliary material. The base material is transparent silicon carbide crystals with numerous microtubes, and the auxiliary material is a colored substance that fills the microtubes of the silicon carbide crystals, imparting color to the colorless, transparent silicon carbide crystals, thus creating colored moissanite. The color of the colored moissanite is determined by the colored substance. By adjusting the colored substance, the color of the moissanite can be adjusted, for example, to purple, pink, red, blue, and so on.

[0052] The crystal form of the silicon carbide crystal is not limited, and conventional crystal forms such as 4H or 6H crystal forms of silicon carbide crystals can be used. The microtube density within the silicon carbide crystal will affect the color of the colored substance. In some embodiments, the microtube density within the silicon carbide crystal is 1 to 500 ea / cm 2 Furthermore, the microtube density in the silicon carbide crystal is 50 to 400 ea / cm 2 For example, the micropipe density in the silicon carbide crystal can be 100 ea / cm 2 、200ea / cm 2、300ea / cm 2 or 400ea / cm 2 If the microtube density in the silicon carbide crystal is too small, the colored material filling in the later stage is relatively small, and the color development is not obvious; if the microtube density in the silicon carbide crystal is too large, it is not conducive to the later gem processing and there is a risk of breakage.

[0053] The diameter of the microtubes affects the filling effect of the colored material. A diameter that is too small is not conducive to the filling of the colored material, and a diameter that is too large is not conducive to the subsequent processing of the gemstone. In some embodiments, the diameter of the microtubes is 5 to 300 μm. Further, the diameter of the microtubes is 50 to 200 μm, for example, 80 μm, 120 μm, 150 μm, 180 μm, or 200 μm, etc.

[0054] The volume percentage of the microtubules affects the color rendering of colored moissanite. If the volume percentage is too small, the color rendering of the colored moissanite will be uneven. If the volume percentage is too large, it will be detrimental to subsequent gem processing and may cause problems such as breakage. In one embodiment, the volume of the microtubules accounts for 0.5% to 45% of the volume of the colored moissanite. Further, the volume of the microtubules accounts for 5% to 40% of the volume of the colored moissanite. For example, the volume of the microtubules accounts for 10%, 20%, 30%, or 40% of the volume of the colored moissanite, etc.

[0055] In some embodiments, the colored substance is an organic colorant, and the solid-state refractive index of the organic colorant is greater than or equal to 1.6. The high refractive index organic colorant has a relatively enhanced scattering effect on light, so that the colorant particles can more effectively reflect and refract light that is complementary to its color, thereby making the color appear more vivid and saturated.

[0056] Furthermore, the organic colorant includes a base material and a coloring material, wherein the base material is a polymer with a refractive index greater than or equal to 1.6, such as a cycloolefin copolymer, a thioether-type episulfide compound, etc., and the coloring material can be selected from some organic dyes, or materials that can produce a coloring reaction, such as phenol and Fe 3+ It appears bluish-purple, benzoic acid and fuchsin appear pink, benzoic acid and phthalocyanine violet / litmus appear purple, and so on.

[0057] See also Figure 1 The present invention also provides a method for preparing colored moissanite, which comprises at least the following steps:

[0058] S1. Preparation of silicon carbide crystals with microtubes;

[0059] S2. Filling colored substances into microtubes of silicon carbide crystals to produce colored moissanite.

[0060] Specifically, step S1 involves doping silicon carbide powder with a material containing micropipe-inducing elements and coordinating the process so that a large number of micropipe defects are generated in the early stages of silicon carbide crystal growth. Then, through the process, the micropipe defects on the surface of the seed crystal are maintained during the continuous growth of the crystal, forming micropipe channels that penetrate the crystal to a certain depth.

[0061] See also Figures 2 to 4 In one embodiment, preparing a silicon carbide crystal with microtubes includes the following steps S11-S14:

[0062] S11. Doping the raw materials with micropipe-inducing elements: placing silicon carbide powder 130 into the crucible 100 , and doping the silicon carbide powder 130 with a material containing micropipe-inducing elements, and then installing the seed crystal cover 110 with the seed crystal 120 fixed thereon on the top of the crucible 100 .

[0063] This step is the charging step: high-purity silicon carbide powder 130 is placed in crucible 100 and doped with a material containing a micropipe-inducing element. The micropipe-inducing element includes, but is not limited to, silicon, cerium, and beryllium. The material containing a micropipe-inducing element includes one or more of cerium oxide, cerium carbide, cerium silicide, beryllium oxide, beryllium carbide, and beryllium silicide. The doping material can be any of the aforementioned materials, such as silicon powder, cerium oxide, or cerium carbide, or a combination of any two or more of them, such as, but not limited to, a combination of cerium oxide and cerium carbide, or a combination of cerium oxide, cerium carbide, and cerium silicide. It should be noted that because silicon powder evaporates at 1400°C, when the doping material is silicon powder, to prevent premature evaporation and depletion of the doping material, the silicon powder must be placed in a graphite crucible, and the graphite crucible must be placed inside the silicon carbide powder 130.

[0064] Furthermore, the amount of the material containing the microtube-inducing element added to the silicon carbide powder is 0.5% to 1%, for example, 0.5%, 0.8% or 1%, etc.

[0065] The seed crystal 120 serves as a structural template for the silicon carbide crystal and has a large number of micropipe defects. The micropipe density of the seed crystal 120 is 0.1 to 1000 ea / cm 2 Furthermore, the microtube density of the seed crystal 120 is 50 to 800 ea / cm 2 For example, the microtubule density is 100 ea / cm 2 、300ea / cm 2 、500ea / cm 2 In addition, the radial deviation angle of the seed crystal 120 from

[0001] is 0° to 8°, such as 0°, 4°, 6° or 8°.

[0066] S12, process induced micro-tube: put the assembled crucible 100 into the furnace body, and evacuate the furnace body to 0.01mbar, and at the same time raise the temperature to 1200-1400℃ and keep it warm for 10-15h; then adjust the pressure in the furnace body to 300-600mbar, and at the same time slowly raise the temperature to 2250-2350℃ in 30h, and then reduce the pressure in the furnace body to 0.6mbar-1.2mbar in 1h, and raise the temperature to 2268-2368℃.

[0067] After the loading in step S11 is completed, the crucible 100 containing the raw materials is placed in a crystal growth furnace. The pressure in the furnace is first evacuated to 0.01 mbar, and the temperature is slowly raised to a microtube induction temperature, such as 1200°C, 1300°C or 1400°C, and maintained at this temperature for 10 hours, 12 hours or 15 hours to ensure that the microtubes on the crystal surface are fully developed; thereafter, argon gas is filled into the furnace to adjust the pressure in the furnace to 300 mbar, 400 mbar, 500 mbar or 600 mbar, and the temperature is slowly raised to 2250°C, 2300°C or 2350°C over 30 hours; the pressure in the furnace is then gradually reduced to 0.6 mbar, 1 mbar or 1.2 mbar over 1 hour, and the temperature is raised to 2268°C, 2300°C or 2368°C, etc.

[0068] S13. Silicon carbide crystal growth: reduce the temperature to 2250-2300°C over 150 h and increase the furnace pressure to 300-500 mbar.

[0069] This step is the stable growth stage of the silicon carbide crystal. During this stage, the microtubes further extend as the crystal grows to form microtube channels with a certain depth.

[0070] S14. Cooling: Cool to room temperature and inflate to atmospheric pressure.

[0071] After the growth is completed, the silicon carbide crystal 240 with a large number of microtubes can be obtained by cooling to room temperature and inflating to atmospheric pressure. Figure 4 Some microtube channels in the silicon carbide crystal run through the seed crystal surface and the growth surface of the crystal. The end of the microtube close to the seed crystal surface is defined as the entrance of the microtube channel, and the end of the microtube close to the growth surface is defined as the exit of the microtube channel.

[0072] See also Figure 1 and Figure 5 Step S2 is to fill the colored substance into the micro-tube structure in the silicon carbide crystal, comprising:

[0073] S21. Crystal pretreatment: If the silicon carbide crystal 240 is thick and large, the silicon carbide crystal 240 is sliced, for example, by cutting off 1 to 3 mm of the upper and lower sections of the crystal so that the microtubes with closed ends form microtube channels 241. Figure 6 If the silicon carbide crystal is thin, slicing is not necessary. Instead, the upper and lower end faces need only be polished flat to form closed-end microtubes into microtube channels 241. The growth end face is defined as the channel entrance, and the seed crystal end face is defined as the channel exit.

[0074] S22, liquid organic colorant preparation: a polymer with a refractive index of 1.6 or above is dispersed in an organic solvent, and a coloring substance is added to prepare a liquid organic colorant 230. The organic solvent is used to disperse the high refractive index polymer and the coloring substance to form a uniform liquid organic colorant. The high refractive index polymer can enhance the coloring effect. The coloring substance is, for example, phenol and Fe 3+ , benzoic acid and fuchsin, benzoic acid and phthalocyanine violet or litmus, etc. The amount of color-developing substance added can be adjusted according to the depth of the desired color and is not limited here.

[0075] S23 , filling with liquid organic colorant: injecting the liquid organic colorant 230 into the micro-tube channel 241 in the silicon carbide crystal 240 .

[0076] See also Figure 7 In one embodiment, a pressure difference can be applied between the inlet and outlet sides of the microtube channel 241. For example, the silicon carbide crystal 240 is placed in the liquid organic colorant 230, and a pressure difference is formed between the inlet and outlet sides of the microtube channel 241, so that the liquid organic colorant 230 flows along the microtube channel 241 until the microtube channel 241 is filled.

[0077] See also Figure 8 and Figure 9 In another embodiment, the contact angle θ between the organic liquid colorant 230 and the silicon carbide crystal 240 is less than 90°. The inlet side of the microtube channel 241 is immersed in the liquid organic colorant 230, allowing the microtubes to be filled with the liquid organic colorant 230. When the contact angle between the liquid organic colorant and the silicon carbide is less than 90°, the liquid organic colorant 230 can spread well on the microtube surface, helping to evenly distribute the color-developing substance on the microtube surface, thereby improving color uniformity and color rendering quality.

[0078] S24. Liquid organic colorant curing: The polymer in the liquid organic colorant is cross-linked and cured by high temperature and / or ultraviolet light. During the curing process, the color-developing substance is evenly dispersed in the cross-linked network structure of the polymer, thereby showing the corresponding color.

[0079] Furthermore, after the solidification is completed, it also includes a gem processing process: the crystal slices filled with colorants or the unprocessed thin crystals are processed into ornamental handicrafts or accessories according to the gem processing technology.

[0080] The technical scheme of the present invention is described in detail below through several specific examples and comparative examples. Unless otherwise stated, the raw materials and reagents used in the following examples are all commercially available commodities, or can be prepared by conventional methods in the art, and the instruments used in the examples are all commercially available. The described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0081] Example 1

[0082] This embodiment provides a method for preparing colored moissanite, comprising the following steps:

[0083] 1) Raw material processing: Figure 2 In the crucible 100 shown, 3.5 kg of high-purity silicon carbide powder 130 is placed, and 0.35 g of a mixture of cerium oxide, cerium carbide, and cerium silicide is evenly mixed into the powder. A first crucible 131 is placed on either side of the center of the silicon carbide powder 130, each containing 3 g of silicon powder. A second crucible 132 is placed at the center of the bottom of the crucible, containing 15 g of silicon powder. A silicon carbide seed crystal 120 is placed on top of the crucible, with a microtube density of 10 ea / cm 2 , and the growth plane has a deflection angle of 0° with respect to the

[0001] direction. The assembled crucible 100 is placed in a crystal growth furnace.

[0084] 2) Process-induced micro-tubes: The furnace pressure was evacuated to 0.01 mbar, and the temperature was slowly raised to 1400°C and maintained for 10 hours. The furnace pressure was then filled with Ar gas to 600 mbar, and the temperature was raised to 2350°C over 30 hours. The pressure in the furnace was then gradually reduced from 600 mbar to 0.6 mbar over another hour, and the temperature was raised to 2368°C.

[0085] 3) Crystal growth: The temperature was lowered to 2300° C. over 150 h, and the pressure was increased to 300 mbar with Ar gas.

[0086] 4) Cooling: Turn off the power, cool to room temperature, and inflate to atmospheric pressure to obtain a silicon carbide crystal 240 with a large number of microtubes, such as Figure 4 shown.

[0087] 5) Crystal slice judgment: The thickness of the obtained crystal reaches 30mm, and the microtubule channel 241 is as follows: Figure 7As shown, extending perpendicularly to the seed crystal surface, the upper and lower end faces of the silicon carbide crystal 240 (moissanite blank) are cut off by 1mm-3mm, so that the microtubes with closed ends form channels, and their growth end faces are defined as channel entrances, and the seed crystal end faces are defined as channel exits.

[0088] 6) Colorant preparation: Dissolve cycloolefin copolymer with a refractive index of 1.6 in carbon tetrachloride, add 0.1% phenol and 0.02% Fe 3+ Liquid organic colorant 230 is prepared.

[0089] 7) If Figure 8 As shown, a silicon carbide crystal 240 is immersed in a liquid organic colorant 230 in a chamber 200. The pressure in the upper part of the chamber 200 is increased to 0.2 MPa through the air inlet 210 of the chamber 200, and the pressure in the lower part of the chamber 200 is reduced to below 0.01 MPa through the air outlet 220 of the chamber 200. While maintaining the pressure, the liquid organic colorant is injected into the micro-tube channel 241 of the silicon carbide crystal 240 ( Figure 7 250 in the figure represents the residual liquid organic colorant flowing out of the micro-tube channel); the filled silicon carbide crystal 240 is placed in a container filled with the liquid organic colorant 230, and the pressure in the container is pumped down to below 0.01 MPa and allowed to stand for 24 hours.

[0090] 8) The liquid organic colorant is cured under the action of ultraviolet light at 80°C;

[0091] Take out the crystal slice filled with dye Figure 10 As shown, the interior is uniformly blue-purple. Using gem processing techniques, the crystals can be processed into ornamental crafts or jewelry. Carbon tetrachloride is somewhat toxic and is only used for illustrative purposes. Other organic solvents can be used for production.

[0092] Example 2

[0093] This embodiment provides a method for preparing colored moissanite, comprising the following steps:

[0094] 1) Raw material processing: Figure 2 In the crucible 100 shown, 5 kg of high-purity silicon carbide powder 130 is placed, and 0.15 g of a mixture of beryllium oxide, beryllium carbide, and beryllium silicide is evenly mixed into the powder. Then, a first crucible 131 is placed on both sides of the center of the silicon carbide powder 130, and 15 g of silicon powder is placed in the first crucible 131. A second crucible 132 is placed at the center of the bottom of the crucible, and 25 g of silicon powder is placed in the second crucible. A silicon carbide seed crystal 120 is placed on the top of the crucible 100, and the microtube density is 50 ea / cm 2 , and the growth surface has a deflection angle of 0° with respect to the

[0001] direction. The assembled crucible 100 is placed into the furnace body.

[0095] 2) Process-induced micro-tubes: The pressure inside the furnace was evacuated to 0.01 mbar, and the temperature was slowly raised to 1350°C and maintained for 15 hours. The pressure inside the furnace was then filled with Ar gas to 300 mbar, and the temperature was raised to 2250°C over 30 hours. The pressure inside the furnace was then gradually reduced from 600 mbar to 1.2 mbar over another hour, and the temperature was raised to 2268°C.

[0096] 3) Crystal growth: The temperature was lowered to 2250° C. over 150 h, and the pressure was increased to 500 mbar with Ar gas.

[0097] 4) Cooling: Turn off the power, cool to room temperature, and inflate to atmospheric pressure.

[0098] 5) Crystal slice judgment: The thickness of the obtained crystal reaches 8mm, and the microtubule channels are as follows Figure 7 As shown, the ends and inner walls of the microtubes are smooth and flat, and the upper and lower end faces of the silicon carbide crystal 240 (moissanite blank) are ground flat so that the microtubes with closed ends form channels, and the growth end face is defined as the channel entrance, and the seed crystal end face is defined as the channel exit.

[0099] 6) Liquid organic colorant preparation: Dissolve benzoic acid in a thioether-type episulfide solvent with a refractive index of 1.6, add 0.1% fuchsin, and heat the mixture to 240-250°C to completely dissolve the organic colorant.

[0100] 7) If Figure 9 As shown, the crystal is placed in the liquid organic colorant 230 so that the liquid organic colorant 230 forms a microtube as shown in FIG. Figure 8 The contact angle θ shown is less than 90°. The pressure inside chamber 200 can be reduced to below 0.05 MPa through the air outlet 220 of chamber 200. Under the action of surface tension and pressure, the liquid organic colorant is injected into the microtube, completing the filling. The filled moissanite rough is placed in a container filled with liquid organic colorant 230, and the pressure in the container is reduced to below 0.01 MPa, and then allowed to stand for 24 hours.

[0101] 8) Curing of the liquid organic colorant is completed under the action of ultraviolet light with a wavelength of 254-365nm;

[0102] Take out the crystal slice filled with colored material. Figure 11 As shown, the interior is evenly pink, and the crystal is processed into ornamental handicrafts or jewelry according to the gem processing technology.

[0103] Comparative Example 1

[0104] Select Figure 2 The crucible 100 shown in FIG. 1 has a seed crystal 130 fixed on the top of the crucible 100. The seed crystal is selected as Figure 3 As shown, the deviation angle is 4° and the microtubule density is less than 0.2ea / cm 2 5 kg of high-purity silicon carbide powder 130 is placed in a crucible 100, and 0.5 g of aluminum oxide is added to the silicon carbide powder 130. The crucible is then placed in a furnace to implement a crystal growth process.

[0105] 2) The pressure inside the furnace was evacuated to 0.1 mbar, and the temperature was slowly raised to 1000°C, maintained for 5 hours, and the pressure was evacuated to 0.001 mbar. The pressure inside the furnace was filled with Ar gas to 600 mbar, and the temperature was raised to 2250°C in 30 hours and kept constant.

[0106] 3) Gradually reduce the pressure in the furnace from 600 mbar to 1 mbar over 30 hours, while maintaining the temperature constant;

[0107] 4) Maintain the process state for 150 h and fill the pressure to 300 mbar with Ar gas.

[0108] 5) Turn off the power, cool to room temperature, and inflate to atmospheric pressure.

[0109] Since the seed crystal 120 deflection angle is 4°, the microtubule development direction and other defect-induced microtubules are deflected to 4° and are easily covered by growth steps during the regrowth process, such as Figure 12 As shown in FIG. 2 , since the depressurization and growth process in step 2) do not effectively control microtubes, microtubes only appear locally in the silicon carbide crystal 240 . Figure 13 Region I in the figure. The doping elements cannot evenly enter the crystal growth interface, resulting in Figure 14 , Moissanite rough with dark color in the early stage and light color in the later stage.

[0110] By comparing Examples 1-2 and Comparative Example 1, it can be found that: Examples 1-2 prepare silicon carbide crystals containing a large number of microtubes, and then use colored substances to fill the microtubes in the silicon carbide crystals to make them appear colored, and the color of the moissanite is determined by the color of the filled colored substance. The colored substance can be selected according to actual needs to obtain moissanite of different colors; while Comparative Example 1 uses the conventional method of doping with Al elements to prepare moissanite. Since the release of aluminum elements in the crystal growth stage cannot be controlled, the color is dark in the early growth stage and light in the later growth stage. The color of the obtained silicon carbide gemstone is uneven and stratified.

[0111] In summary, the present invention provides colored moissanite and its preparation method. The main structure of the moissanite is silicon carbide crystals with a microtubular structure. A colored substance is filled within the microtubules to enhance the moissanite's color. The color of the moissanite is determined by the added colored substance, resulting in low-cost, high-yield moissanite in a variety of colors.

[0112] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A colored moissanite, characterized in that: include: The bulk material is a transparent silicon carbide crystal with microtubes, and the microtube density in the silicon carbide crystal is 1 to 500 ea / cm 2 ; Auxiliary material, the auxiliary material is a colored substance, and the colored substance is filled in the microtubes of the silicon carbide crystal.

2. The colored moissanite according to claim 1, characterized in that: The diameter of the microtube is 5 to 300 μm.

3. The colored moissanite according to claim 1, characterized in that: The volume of the microtubes accounts for 0.5% to 45% of the volume of the colored moissanite.

4. The colored moissanite according to claim 1, characterized in that: The main body material is 4H or 6H crystal silicon carbide crystal.

5. The colored moissanite according to claim 1, characterized in that: The auxiliary material is an organic colorant, and the solid-state refractive index of the organic colorant is greater than or equal to 1.

6.

6. A method for preparing colored moissanite according to any one of claims 1 to 5, characterized in that: The following steps are involved: Preparation of silicon carbide crystals with microtubes; Colored substances are filled into the microtubes of the silicon carbide crystals to produce colored moissanite.

7. The method for preparing colored moissanite according to claim 6, characterized in that: The step of preparing the silicon carbide crystal with microtubes comprises: Putting silicon carbide powder into a crucible, doping the silicon carbide powder with a material containing a microtube-inducing element, and then installing a seed crystal cover with a seed crystal fixed thereon on the top of the crucible; Place the assembled crucible into a furnace, evacuate the furnace to 0.01 mbar, and heat it to 1200-1400°C for 10-15 hours. Adjust the pressure in the furnace to 300-600 mbar, and slowly heat it to 2250-2350°C over 30 hours. Then, reduce the pressure in the furnace to 0.6-1.2 mbar over 1 hour, and raise the temperature to 2268-2368°C. Lower the temperature to 2250-2300°C over 150 h and increase the furnace pressure to 300-500 mbar; The mixture was cooled to room temperature and inflated to atmospheric pressure to obtain a silicon carbide crystal with microtubes.

8. The method for preparing colored moissanite according to claim 7, characterized in that: The micropipe inducing elements include one or more of silicon, beryllium and cerium; the doping amount of the material containing the micropipe inducing elements accounts for 0.5% to 1% of the silicon carbide powder.

9. The method for preparing colored moissanite according to claim 6, characterized in that: The step of filling a colored substance into the microtubes of the silicon carbide crystal comprises: Pre-treating the silicon carbide crystal so that the microtubes with closed ends form microtube channels; Dispersing a polymer having a refractive index greater than or equal to 1.6 in an organic solvent, and adding a coloring substance to prepare a liquid organic colorant; Injecting the liquid organic colorant into the micro-tube channel of the silicon carbide crystal under the action of pressure difference or surface tension; The liquid organic colorant in the microtube channel is solidified.

10. The method for preparing colored moissanite according to claim 7, characterized in that: The microtube density of the seed crystal is 0.1 to 1000 ea / cm 2 , and the radial deviation angle [0001] is 0°~8°.

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