Composite material and preparation method and application thereof

Abstract

The present invention relates to the technical field of semiconductor materials, and provides a composite material and a preparation method and application thereof. The preparation method comprises: (1) injecting Ta source gas, C source gas and reducing gas into a deposition chamber at one time, and depositing a TaC sublayer on a substrate by CVD under the control of an adaptive pressure control device; (2) after the deposition is completed, repeating step (1) at least once, and depositing at least another TaC sublayer on the TaC sublayer in step (1) to obtain the composite material. The TaC coating deposited by the pulse deposition method of the present invention can alleviate the problem of thermal expansion coefficient mismatch between TaC and carbon-based substrates, improve the thermal shock resistance of the product, and improve the toughness of the product and the bonding strength between the coatings.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a composite material and a preparation method and application thereof. Background Art

[0002] Carbon-based substrates such as graphite and C / C composites are widely used in semiconductors, aerospace, energy vehicles and other fields. However, carbon-based substrates are easily oxidized in high-temperature oxygen environments, are not resistant to ammonia, and are very soft and easily scratched, which seriously restricts their development and practical application. Therefore, scholars covered the surface of the carbon-based substrate with a layer of SiC coating to protect the graphite from corrosion and other effects. However, as the requirements for the use of carbon material devices in the semiconductor field are further improved, SiC no longer meets its requirements in some special scenarios. For example, H2 will promote the gasification of SiC at 1600 °C, which will cause the SiC coating to be slowly corroded. SiC will also be gasified under conditions exceeding 2300 °C, resulting in excessive differences in the surface roughness of the coating, causing uneven surface temperature distribution; or the SiC coating is corroded through, further rapidly corroding the internal graphite substrate, leaving only a thin layer of SiC coating on the surface.

[0003] Tantalum carbide TaC is one of the best candidate materials to replace SiC. TaC is an ultra-high temperature material that can still be used normally above 2000 ℃. It has excellent high-temperature mechanical stability and high-temperature corrosion resistance and ablation resistance. TaC has good chemical compatibility and mechanical compatibility with carbon materials and can effectively protect carbon materials. Depositing TaC on the surface of a carbon-based substrate can make the carbon material have good thermal shock resistance, oxidation resistance and excellent thermochemical stability. Therefore, TaC coatings are widely used in single crystal growth, energy electronics and other fields.

[0004] However, when a single-phase TaC coating is directly coated on the surface of a carbon-based substrate, the thermal expansion coefficient mismatch between TaC and the carbon-based substrate will cause the coating to crack under multiple high and low temperature thermal cycles, exposing the carbon-based substrate to the environment, causing the carbon-based substrate to participate in the reaction and be consumed, releasing carbon impurities. Therefore, how to alleviate or even avoid the thermal expansion coefficient mismatch between the TaC coating and the carbon-based substrate is an urgent problem to be solved. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and to provide a composite material and a preparation method and application thereof. The present invention uses a pulse deposition method to obtain a TaC coating comprising a sub-layer composed of multiple layers of small-size TaC particles, which can alleviate the problem of mismatch in thermal expansion coefficients between TaC and a carbon-based substrate, and the preparation method can also improve the utilization rate of raw materials.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a method for preparing a composite material, which method comprises the following steps: (1) injecting Ta source gas, C source gas and reducing gas into a deposition chamber at one time, and depositing a TaC sublayer on a substrate by CVD under the control of an adaptive pressure control device; (2) after the deposition is completed, repeating step (1) at least once, and depositing at least another TaC sublayer on the TaC sublayer in step (1) to obtain the composite material; the conditions of each CVD deposition are the same or different, and the conditions of each CVD deposition include: a deposition temperature of 1500°C-1900°C, a pressure of 2 kPa-12 kPa, and an amount of gas introduced each time so that the thickness of a single TaC sublayer is 0.1 μm-4 μm; in the gas injected for each CVD deposition, the molar ratio of Ta source gas, C source gas and reducing gas is 1:0.5-1.5:0.1-20.

[0007] A second aspect of the present invention provides a composite material, wherein the composite material is a composite material prepared by the preparation method described in the first aspect.

[0008] Preferably, the composite material comprises a substrate and a TaC coating located on the surface of the substrate; the TaC coating comprises at least two TaC sublayers, and the XRD pattern of the surface of the TaC coating comprises characteristic diffraction peaks corresponding to the (111) crystal plane, the (200) crystal plane, the (220) crystal plane, the (311) crystal plane, the (222) crystal plane and the (400) crystal plane, wherein the intensity I of the (200) crystal plane is (200) The strength I with (220) crystal plane (220) The ratio satisfies: 0.2≤I (200) / I (220) <1; the strength of (111) crystal plane I (111) The strength I with (200) crystal plane (200) The ratio satisfies: 1≤I (111) / I (200) ≤5; the thickness of the single TaC sublayer is 0.1 μm-4 μm; in the TaC coating, the average grain size of the TaC grains is less than 6 μm.

[0009] The third aspect of the present invention provides use of the composite material described in the second aspect as a high temperature resistant material.

[0010] The present invention adopts the above technical solution to have the following beneficial effects: compared with directly and continuously depositing TaC coating on the substrate, pulse feeding deposition of TaC coating can form a dense multilayer TaC coating containing TaC grains with smaller particle size, which is conducive to enhancing the toughness of the coating, avoiding the formation of through cracks, and improving the oxidation resistance and service life of the coating. On the other hand, compared with the columnar crystals prepared by the conventional deposition process, the fine-grained TaC prepared by the method of the present invention can give the coating higher toughness and strength, which can improve the bonding strength between the coating and the substrate, and further improve the service life, thermal shock resistance and oxidation resistance of the coating.

[0011] In addition, when depositing the coating, conventional chemical vapor deposition (CVD) technology continuously supplies raw materials to the chamber, and then continuously extracts the gas through a vacuum pump. However, some unreacted gases or intermediate products will be directly extracted, especially the gaseous Ta source, which will condense and crystallize in the exhaust pipe, which can easily cause pipe blockage or increase the burden of later maintenance, and also cause great waste. In addition, during the deposition stage, the vacuum pump works uninterruptedly for a long time, which will seriously affect the service life of the vacuum pump. The multi-layer TaC coating process proposed in the present invention feeds materials in a pulsed manner, and then completes the reaction of the raw materials. After the pressure is stabilized, the gas can be evacuated and ventilated. Not only does it have a higher raw material utilization rate, but the pulsed feeding can also reduce the long-term use of the vacuum pump, extend the life of the vacuum pump, avoid pipe blockage, reduce energy consumption in the production process, and reduce maintenance costs, and it is simple to operate.

[0012] The endpoints and any values ​​of the range disclosed in this article are not limited to the precise range or value, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article. Herein, in the absence of special instructions, data ranges include endpoints. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Shown is the SEM image of the composite material prepared in Example 1.

[0014] Figure 2 Shown are the distribution diagrams of the C element (Figure a) and the Ta element (Figure b) of the composite material prepared in Example 1.

[0015] Figure 3 Shown is the XRD pattern of the TaC coating surface in the composite material prepared in Example 1.

[0016] Figure 4Shown is the XRD pattern of the TaC coating surface in the composite material prepared in Comparative Example 1. DETAILED DESCRIPTION

[0017] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0018] Unless otherwise defined, all scientific and technical terms used in the present invention have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention relates.

[0019] A first aspect of the present invention provides a method for preparing a composite material, the method comprising the following steps: (1) injecting Ta source gas, C source gas and reducing gas into a deposition chamber at one time, and depositing a TaC sublayer on a substrate by CVD under the control of an adaptive pressure control device; (2) after the deposition is completed, repeating step (1) at least once, depositing at least another TaC sublayer on the TaC sublayer in step (1) to obtain the composite material; the conditions of each CVD deposition are the same or different, and the conditions of each CVD deposition include: a deposition temperature of 1500°C-1900°C (for example, 1500°C, 1550°C, 1600°C, 1650°C, 1700°C, 1750°C, 1800°C, 1850°C or 1900°C), and a pressure of 2 kPa-12 kPa (for example, 2 kPa, 3 kPa, 4 kPa, 5 kPa, 6 kPa, 7 kPa, 8 kPa, 9 kPa, 10 kPa, 11 kPa, 12 kPa, 13 kPa, 14 kPa, 15 kPa, 16 kPa, 17 kPa, 18 kPa, 19 kPa, 20 kPa, 21 kPa, 22 kPa, 23 kPa, 24 kPa, 25 kPa, 26 kPa, 27 kPa, 28 kPa, 29 kPa, 30 kPa, 31 kPa, 32 kPa, 33 kPa, 34 kPa, 35 kPa, 36 kPa, 37 kPa, 38 kPa, 39 kPa, 40 kPa, 41 kPa, 42 kPa, 43 kPa, 44 kPa, 45 kPa, 46 kPa or 12 kPa), the amount of gas introduced each time makes the thickness of the single-layer TaC sublayer 0.1 μm-4 μm; in the gas injected for each CVD deposition, the molar ratio of Ta source gas, C source gas and reducing gas is 1:0.5-1.5 (for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5):0.1-20 (for example, 0.1, 0.5, 1, 5, 10, 15, 20).

[0020] The substrate may be, for example, at least one of a carbon-based substrate, a silicon-based substrate and a SiC substrate, and may be a substrate or a substrate to which a transition layer has been attached (for example, the substrate may include a carbon-based substrate and a SiC coating attached to the carbon-based substrate).

[0021] In some embodiments, the substrate is a carbon-based substrate.

[0022] In some embodiments, the carbon-based substrate has a thermal expansion coefficient of 4×10 -6 / k -7.5×10 -6 / k, density is 1.7-2.2 g / cm 3 , porosity is 5%-25%, and grain size is less than 4 μm.

[0023] In some embodiments, the carbon-based substrate is graphite (such as isostatic graphite) or carbon fiber reinforced carbon.

[0024] Since TaC deposition is a decomposition reaction, TaCl5+CH4+H2→TaC+HCl, the pressure will increase after the gas is introduced into the chamber for reaction. The pressure can be stabilized by adaptively adjusting the opening of the pressure control device (such as an adaptive pressure control valve). The judgment of the reaction end point can be adjusted according to the specific type of valve selected. For example, when the valve opening is more than 5%, and the pressure rise rate is less than 100 Pa / min for more than 2 minutes, the reaction is considered complete, and then the "inflation-exhaust-inflation" cycle can be started or the deposition can be terminated. In some embodiments, the time of each deposition can be 5 min-4 h, such as 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 2 h, 3 h or 4 h.

[0025] In some embodiments, the method further comprises pre-treating the substrate before deposition. The pre-treatment removes impurities on the substrate surface, for example, the substrate may be cleaned first. The cleaning process may be performed by water washing, acid washing, rinsing and / or immersion, and may be performed by conventional means in the art, as long as the impurities on the substrate surface can be removed.

[0026] It should be understood that after cleaning, the substrate may be dried and then used in the subsequent deposition process. The drying method may be a conventional drying method, such as using a vacuum dryer or air blast drying (may be dried at 100°C-300°C for more than 2 hours).

[0027] After drying, the substrate surface can be further processed, including but not limited to grinding, sandblasting, plasma treatment and other processes, so that the substrate surface has a certain roughness (Ra=0.2 μm-2 μm) and high cleanliness to ensure close bonding between the coating and the substrate.

[0028] The method for depositing the TaC coating of the present invention is CVD deposition, and the equipment used can be a CVD vapor deposition furnace. The substrate can be placed horizontally in the deposition reaction chamber, the furnace door is closed, the reaction chamber is evacuated to a vacuum below 200 Pa, and then the temperature is increased to the deposition temperature at 2°C / min-10°C / min.

[0029] In some embodiments, the Ta source gas includes at least one of TaF5, TaCl5, and TaBr5.

[0030] In some embodiments, the C source gas includes at least one of CH4, C2H4, C2H6, C3H6, and C3H8.

[0031] In some embodiments, the reducing gas is hydrogen.

[0032] In some embodiments, the gas injected during each CVD deposition also includes a dilution gas, which may be an inert gas, that is, a gas that does not react with other components, such as argon Ar or helium He.

[0033] In some embodiments, in the gas injected during each CVD deposition, the molar ratio of the Ta source gas to the diluent gas is 1:0.1-20.

[0034] In the present invention, the amount of gas introduced each time is such that the thickness of the single-layer TaC sublayer is 0.1 μm-4 μm (for example, 0.1 μm, 0.4 μm, 0.8 μm, 1.2 μm, 1.6 μm, 2 μm, 2.4 μm, 2.8 μm, 3.2 μm, 3.6 μm or 4 μm). Those skilled in the art can also make calculations based on the substrate size and the reactor volume.

[0035] The type and proportion of gas injected and the deposition conditions for each CVD deposition can be the same or different. There are gas filling and exhaust processes in each deposition process. Ar and the reaction gas that does not participate in the reaction, and the HCl gas generated during the reaction are exhausted during the exhaust process. Each time the pressure is pumped to 500 Pa -1000 Pa (absolute pressure), it is considered that the gas is completely exhausted.

[0036] There is no particular limit to the number of depositions as long as the required coating thickness is achieved. It can be more than 3 times, such as 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20 or even more times.

[0037] After obtaining the final product, a vacuum cooling operation can be performed. The specific operation method can be a conventional operation method in the field. For example, after the last deposition is completed, the furnace can be evacuated to below 200 Pa, and the temperature can be gradually reduced to room temperature at a cooling rate of 2°C / min-10°C / min. Then, 20 L / min-200 L / min of Ar or N2 is introduced to adjust the pressure to normal pressure, and then the furnace is opened to take out the product.

[0038] A second aspect of the present invention provides a composite material, wherein the composite material is a composite material prepared by the preparation method described in the first aspect.

[0039] In some embodiments, the composite material comprises a substrate and a TaC coating located on a surface of the substrate.

[0040] In some embodiments, the TaC coating comprises at least two TaC sublayers, and the XRD pattern of the surface of the TaC coating comprises characteristic diffraction peaks corresponding to the (111) crystal plane, the (200) crystal plane, the (220) crystal plane, the (311) crystal plane, the (222) crystal plane, and the (400) crystal plane, wherein the intensity I of the (200) crystal plane is (200) The strength I with (220) crystal plane (220) The ratio satisfies: 0.2≤I (200) / I (220) <1 (for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99); the strength of the (111) crystal plane I (111) The strength I with (200) crystal plane (200) The ratio satisfies: 1≤I (111) / I (200) ≤5 (for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5); the thickness of the single TaC sublayer is 0.1 μm-4 μm (for example, 0.1 μm, 0.4 μm, 0.8 μm, 1.2 μm, 1.6 μm, 2 μm, 2.4 μm, 2.8 μm, 3.2 μm, 3.6 μm or 4 μm); in the TaC coating, the average grain size of the TaC grains is less than 6 μm (for example, 0.01 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm or 6 μm).

[0041] In the present invention, the grain size can be measured and calculated by observing the coating surface with an optical microscope or a scanning electron microscope and using Image J software.

[0042] In the present invention, the characteristic diffraction peaks corresponding to the (111) crystal plane, (200) crystal plane, (220) crystal plane, (311) crystal plane, (222) crystal plane and (400) crystal plane obtained by XRD on the surface of the TaC coating are 2 θ They are 33.8°-36.2°, 39.6°-42.0°, 57.7°-59.8°, 69.2°-71.2°, 73.0°-74.6° and 87.0°-88.5° respectively. The characteristic diffraction peaks of each crystal plane are independent of each other and have no overlap.

[0043] In some embodiments, the intensity I of the (111) crystal plane (111) The strength I of the (311) crystal plane (311) The ratio satisfies: 1.5≤I (111) / I (311)≤5, for example, 1.5, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 4 or 5.

[0044] In some embodiments, the intensity I of the (111) crystal plane (111) The strength I of the (222) crystal plane (222) The ratio satisfies: 3≤I (111) / I (222) ≤8, for example, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8.

[0045] In some embodiments, the intensity I of the (111) crystal plane (111) The strength of the (400) crystal plane is (400) The ratio satisfies: 10≤I (111) / I (400) ≤50, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50.

[0046] In some embodiments, the TaC coating has a thickness of 3 μm-40 μm, for example, 3 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm or 40 μm.

[0047] In some embodiments, the number of TaC sublayers in the TaC coating may be more than 3 layers, such as 3 layers, 4 layers, 5 layers, 6 layers, 8 layers, 10 layers, 12 layers, 14 layers, 16 layers, 18 layers, 20 layers or even more.

[0048] In some embodiments, in the TaC coating, the content of Ta element is 90 wt%-95 wt%, for example, 90 wt%, 90.5 wt%, 91 wt%, 91.5 wt%, 92 wt%, 92.5 wt%, 93 wt%, 93.5 wt%, 94 wt%, 94.5 wt% or 95 wt%, and the content of C element is 5 wt%-10 wt%, for example, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt% or 10 wt%.

[0049] In the present invention, the method for determining the content of each element is energy dispersive X-ray spectroscopy, and a point is taken in the coating area for point scanning to obtain the content of each element.

[0050] The third aspect of the present invention provides use of the composite material described in the second aspect as a high temperature resistant material.

[0051] The composite material can be used as a carbon material device, for example, and can be applied to the fields of single crystal growth, energy electronics, aerospace, semiconductors, energy vehicles, etc.

[0052] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0054] The present invention is described in detail below in conjunction with specific embodiments, which are used to understand but not to limit the present invention.

[0055] Example 1

[0056] (1) The graphite substrate surface was rinsed, soaked and rinsed with deionized water to remove the graphite powder on the surface, and then vacuum dried at 120 °C for 3 h to ensure that the moisture in the substrate was completely removed; the graphite surface was then sandblasted to make the roughness Ra of the graphite substrate surface about 1 μm.

[0057] (2) Place the graphite substrate in a CVD deposition furnace equipped with an adaptive exhaust valve, evacuate and heat to a deposition temperature of 1700 °C, then introduce TaCl5, H2, Ar and CH4 into the CVD deposition furnace, then stop the ventilation and keep the temperature constant. Adjust the pressure through the adaptive exhaust valve to control the pressure during the deposition process to 8 kPa (fluctuation range of ±5%) to deposit the TaC sublayer. After the reaction is completed, introduce TaCl5, H2, Ar and CH4 again to deposit the TaC sublayer, and finally obtain a composite material covered with 12 layers of TaC sublayers. Among them, the molar ratio of TaCl5:CH4:H2:Ar in each gas introduced is 1:1:8:12; the amount of TaCl5 introduced each time is 50 g, so that the thickness of the TaC sublayer is about 1 μm, and each cycle (i.e., the time for each deposition of the TaC coating) is about 10 min.

[0058] SEM images of TaC coatings Figure 1 As shown, in the composite material, the TaC coating comprises a multi-layered structure. In the composite material, the distribution diagram of C element and Ta element is as shown in Figure 2 As shown in Figure 2, the content of Ta element in the TaC coating is 93.2 wt% and the content of C element is 6.8 wt%. The XRD pattern of the TaC coating surface is shown in Figure 2. Figure 3 As shown, the coating surface is 2 θ The characteristic diffraction peaks of (111) crystal plane, (200) crystal plane, (220) crystal plane, (311) crystal plane, (222) crystal plane and (400) crystal plane are at 33.8°-36.2°, 39.6°-42.0°, 57.7°-59.8°, 69.2°-71.2°, 73.0°-74.6° and 87.0°-88.5°, respectively. (200) / I (220) is 0.34, I (111) / I (200) is 3.10, I (111) / I (311) is 2.6, I (111) / I (222) is 5.9, I (111) / I (400) The average grain size of TaC grains in the TaC coating is about 4 μm.

[0059] Example 2

[0060] The method described in Example 1 was followed, except that the deposition temperature of the coating was different, as shown below.

[0061] Example 2a: The deposition temperature of each layer was 1600° C. and the pressure at the beginning of deposition was 5 kPa.

[0062] Example 2b: The deposition temperature of each layer is 1800° C. and the pressure at the beginning of deposition is 10 kPa.

[0063] In the prepared TaC coating, the data of the size of the TaC sublayer grains and the ratio of the peak intensity in the XRD pattern are shown in Table 1.

[0064] Example 3

[0065] The operation is performed according to the method described in Example 1, except that the number of TaC sublayers is different, as shown below.

[0066] Example 3a: Deposition was performed three times, and the number of TaC sublayers in the obtained composite material was 3.

[0067] Example 3b: Deposition was performed 6 times, and the number of TaC sub-layers in the obtained composite material was 6.

[0068] Example 3c: Deposition was performed 9 times, and the number of TaC sub-layers in the obtained composite material was 9.

[0069] In the prepared TaC coating, the size of the TaC sublayer grains and the ratio of the peak intensity in the XRD pattern are (200) / I (220) and I (111) / I(200) The data are basically consistent with those in Example 1.

[0070] Example 4

[0071] The operation is performed according to the method described in Example 1, except that the thickness of the TaC sublayer is different, as shown below.

[0072] Example 4a: The amount of TaCl5 introduced each time is 100 g, so that the thickness of the TaC sublayer is about 2 μm.

[0073] Example 4b: The amount of TaCl5 introduced each time is 20 g, so that the thickness of the TaC sublayer is about 0.4 μm.

[0074] In the prepared TaC coating, the thickness of the TaC coating, the size of the TaC sublayer grains, the ratio of the peak intensity in the XRD pattern (200) / I (220) and I (111) / I (200) The data are shown in Table 1.

[0075] Example 5

[0076] The operation was carried out according to the method described in Example 1, except that the dosage ratios of the components were different, as shown below.

[0077] Example 5a: The molar ratio of TaCl5:CH4:H2:Ar is 1:1:6:9;

[0078] Example 5b: The molar ratio of TaCl5:CH4:H2:Ar is 1:1:10:15.

[0079] In the prepared TaC coating, the size of the TaC sublayer grains and the ratio of the peak intensity in the XRD pattern are (200) / I (220) and I (111) / I (200) The data are shown in Table 1.

[0080] Comparative Example 1

[0081] The method described in Example 1 (gas molar ratio, temperature, pressure) was followed, except that the TaC coating was continuously deposited for 120 min at a Ta source feed rate of 50 g / min, and the obtained TaC coating reached a thickness of about 12 μm, thereby finally obtaining a composite material covered with a TaC coating.

[0082] The average grain size of the TaC coating is about 10 μm, which is about 2.5 times the grain size of the TaC coating in Example 1. The XRD pattern of the TaC coating surface is shown in FIG. Figure 4As shown, the coating surface has characteristic diffraction peaks of (111) crystal plane, (200) crystal plane, (220) crystal plane, (311) crystal plane, (222) crystal plane and (400) crystal plane at 35.1°, 40.6°, 58.6°, 70.1°, 73.7° and 87.7°, respectively, wherein I (200) / I (220) is 1.8, I (111) / I (200) In addition, it is calculated that the amount of TaCl5 consumed is 6 kg.

[0083] Table 1

[0084]

[0085] It can be seen from the data in Table 1 that the pulsed deposition method of the present invention can deposit multiple layers of TaC layers with small grains, and the grain size is less than 0.5 times that of the conventional continuous deposition method. The diffraction intensity of the surface of the TaC coating in the composite material of the present invention is the highest at the (111) crystal plane, followed by the (220) crystal plane and the (200) crystal plane; the diffraction intensity of the (220) crystal plane of the TaC coating surface obtained by continuous deposition according to the conventional method is less than the diffraction intensity of the (220) crystal plane.

[0086] Test Case

[0087] The performance of the composite materials prepared in the examples and comparative examples was evaluated by the following method. The results are shown in Table 2.

[0088] (1) Evaluation of seismic performance: The sample to be tested is heated to 2000°C at a rate of 10°C / min and then kept at this temperature for 20 min. It is then purged with argon gas at a rate of 100 L / min and air-cooled to below 200°C. The sample surface is then observed for obvious cracks or coating shedding. If no cracks or coating shedding are observed, the sample is placed in a thermal shock furnace and heated up. If cracks or coating shedding occur, the test is stopped. This operation is repeated until cracking occurs. The result is expressed as the number of cycles at cracking. For example, if the number of cycles is 45, it means that cracking or shedding occurs at the 45th cycle.

[0089] (2) Fracture toughness evaluation: According to the indentation method, the polished TaC coating sample was tested using a Vickers hardness tester with a pressure of 100 g in MPa.

[0090] (3) Bond strength evaluation: According to the national standard GB / T 31541-2015 / ISO 13124:2011 Fine ceramic interface tensile and shear bond strength test method cross-cross method.

[0091] Table 2

[0092]

[0093] It can be seen from the data in Table 2 that the thermal shock resistance, fracture toughness and bonding strength of the coating in Comparative Example 1 are significantly worse than those of the coating prepared in the example.

[0094] From the comparison of the embodiments, it can be seen that the performance of the coating is affected by the deposition conditions (Example 2 Group), the number of sub-layers (Example 3 Group), the sub-layer thickness (Example 4 Group), and the gas ratio (Example 5 Group), among which the number of sub-layers and the sub-layer thickness have the greatest influence on the toughness, followed by the influence of the gas ratio; the thinner the sub-layer thickness, the higher the toughness and the better the thermal shock resistance, but the bonding strength is slightly worse.

[0095] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite material, It is characterized in that The method uses pulse feeding to deposit TaC coating, comprising the following steps: (1) Injecting Ta source gas, C source gas and reducing gas into the deposition chamber at one time, and depositing a TaC sublayer on the substrate by CVD under the control of an adaptive pressure control device; (2) after the deposition is completed, repeating step (1) at least once, depositing at least another TaC sub-layer on the TaC sub-layer in step (1) to obtain the composite material; The conditions of each CVD deposition are the same or different, and the conditions of each CVD deposition include: a deposition temperature of 1500° C.-1900° C., a pressure of 2 kPa-12 kPa, and an amount of gas introduced each time so that the thickness of the single-layer TaC sublayer is 0.1 μm-4 μm; In the gases injected during each CVD deposition, the molar ratio of the Ta source gas, the C source gas and the reducing gas is 1:0.5-1.5:0.1-20.

2. The preparation method according to claim 1, It is characterized in that The substrate is a carbon-based substrate; and / or The Ta source gas contains TaF 5 、TaCl 5 and TaBr 5 At least one of; and / or The C source gas contains CH 4 , C 2 H 4 , C 2 H 6 , C 3 H 6 and C 3 H 8 At least one of; and / or The reducing gas is H 2 .

3. The preparation method according to claim 1, It is characterized in that The gas injected during each CVD deposition also contains a diluent gas.

4. The preparation method according to claim 3, It is characterized in that The diluent gas is Ar or He; and / or In the gas injected during each CVD deposition, the molar ratio of the Ta source gas to the dilution gas is 1:0.1-20.

5. A composite material, It is characterized in that The composite material is a composite material prepared by the preparation method according to any one of claims 1 to 4.

6. The composite material according to claim 5, It is characterized in that The composite material comprises a substrate and a TaC coating located on the surface of the substrate; The TaC coating comprises at least two TaC sublayers, and the XRD pattern of the surface of the TaC coating comprises characteristic diffraction peaks corresponding to the (111) crystal plane, the (200) crystal plane, the (220) crystal plane, the (311) crystal plane, the (222) crystal plane and the (400) crystal plane, wherein the intensity I of the (200) crystal plane is (200) The strength I with (220) crystal plane (220) The ratio satisfies: 0.2≤I (200) / I (220) <1; the strength of (111) crystal plane I (111) The strength I with (200) crystal plane (200) The ratio satisfies: 1≤I (111) / I (200) ≤5.

7. The composite material according to claim 6, It is characterized in that The thickness of the single TaC sublayer is 0.1 μm-4 μm; and / or The thickness of the TaC coating is 3 μm-40 μm; and / or In the TaC coating, the average grain size of TaC grains is less than 6 μm.

8. The composite material according to claim 6, It is characterized in that Strength of (111) crystal plane I (111) The strength I of the (311) crystal plane (311) The ratio satisfies: 1.5≤I (111) / I (311) ≤5; and / or Strength of (111) crystal plane I (111) The strength I of the (222) crystal plane (222) The ratio satisfies: 3≤I (111) / I (222) ≤8; and / or Strength of (111) crystal plane I (111) The strength of the (400) crystal plane is (400) The ratio satisfies: 10≤I (111) / I (400) ≤50.

9. The composite material according to any one of claims 6 to 8, It is characterized in that In the TaC coating, the content of Ta element is 90 wt%-95 wt%, and the content of C element is 5 wt%-10 wt%.

10. Use of the composite material according to any one of claims 5 to 9 as a high temperature resistant material.

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