阅读说明：本技术 一种碳基材料表面HfB2-SiC抗氧化涂层的制备方法 (HfB on surface of carbon-based material2Preparation method of-SiC oxidation resistant coating ) 是由 任宣儒 褚洪傲 冯培忠 王炜光 吕君帅 李伟 武科佑 张安妮 朱路 陈鹏 杨青青 于 2019-10-16 设计创作，主要内容包括：本发明公开了一种碳基材料表面HfB_2-SiC抗氧化涂层的制备方法,称量一定比例的HfB_2、SiC粉体并均匀混合,在石墨模具内用均匀混合的粉体包裹碳基体,将装好试样的模具放入放电等离子烧结炉中进行烧结处理,烧结温度为1200-1900℃,升温速率为5-200℃/min,压力为5-50MPa,保温时间5-300min,在碳基体表面得到HfB2-SiC抗氧化涂层。本发明中将放电等离子烧结法应用到碳基材料表面HfB_2-SiC抗氧化涂层的制备中,能够在较低的温度下快速烧结制备出高致密、低缺陷HfB_2-SiC抗氧化涂层。(The invention discloses HfB on the surface of a carbon-based material 2 The preparation method of the-SiC oxidation resistant coating comprises the steps of weighing HfB with a certain proportion 2 And uniformly mixing the SiC powder, wrapping the carbon substrate with the uniformly mixed powder in a graphite mold, putting the mold filled with the sample into a discharge plasma sintering furnace for sintering treatment, wherein the sintering temperature is 1200-1900 ℃, the heating rate is 5-200 ℃/min, the pressure is 5-50MPa, and the heat preservation time is 5-300min, so that the HfB2-SiC oxidation resistant coating is obtained on the surface of the carbon substrate. In the invention, the discharge plasma sintering method is applied to HfB on the surface of the carbon-based material 2 In the preparation of the-SiC oxidation resistant coating, HfB with high compactness and low defect can be prepared by rapid sintering at lower temperature 2 -SiC oxidation resistant coating.)

1. HfB on surface of carbon-based material₂The preparation method of the-SiC oxidation resistant coating is characterized by comprising the following steps: weighing a certain proportion of HfB₂Mixing the SiC powder uniformly, wrapping the carbon substrate with the uniformly mixed powder in a graphite mould, and synthesizing HfB on the surface of the carbon substrate by adopting a discharge plasma sintering method₂-SiC oxidation resistant coating.

2. The carbon-based material surface HfB of claim 1₂The preparation method of the-SiC oxidation resistant coating is characterized by comprising the following specific steps:

(1) surface treatment of the carbon substrate: grinding the carbon substrate for multiple times by using abrasive paper with different roughness, then cleaning by using alcohol, and finally airing to be dry;

(2) mixing materials: firstly, respectively weighing HfB2 powder and SiC powder with certain mass fractions, and uniformly mixing the two powders by using a ball mill to prepare HfB2-SiC composite powder;

(3) die filling: wrapping the carbon matrix treated in the step (1) with the HfB2-SiC composite powder obtained in the step (2) in a graphite mold, so that the carbon matrix is uniformly wrapped by the composite powder;

(4) spark plasma sintering: and (3) placing the mold with the sample in a discharge plasma sintering furnace for sintering treatment, wherein the sintering temperature is 1900 ℃, the heating rate is 5-200 ℃/min, the pressure is 5-50MPa, and the heat preservation time is 5-300min, so that the HfB2-SiC oxidation resistant coating is obtained on the surface of the carbon substrate.

3. The carbon-based material surface HfB of claim 2₂The preparation method of the-SiC oxidation resistant coating is characterized by comprising the following steps: the carbon substrate is graphite or a C/C composite material.

4. The carbon-based material surface HfB of claim 2₂The preparation method of the-SiC oxidation resistant coating is characterized by comprising the following steps: in the above step (2), HfB₂HfB in-SiC composite powder₂The mass fraction is 5-95%, the mass fraction of SiC is 5-95%, the rotation speed of the ball mill is 50-1000r/min, and the ball milling time is 0.5-10 hours.

5. The carbon-based material surface HfB of claim 2₂The preparation method of the-SiC oxidation resistant coating is characterized by comprising the following steps: HfB described in the above step (2)₂And the purity of the SiC powder is more than or equal to 99.0 percent, and the granularity is less than or equal to 50 mu m.

6. The carbon-based material surface HfB of claim 2₂The preparation method of the-SiC oxidation resistant coating is characterized by comprising the following steps: in the step (3), the HfB is covered on the periphery of the substrate₂The thickness of the-SiC composite powder is about 0.1 to 3 times of the thickness of the carbon matrix.

Technical Field

The invention relates to the technical field of carbon materials, in particular to a method for preparing HfB on the surface of a carbon-based material by a plasma discharge sintering method₂-SiC oxidation resistant coating.

Background

Carbon materials (C/C composite materials or graphite) have good high temperature resistance, electrical conductivity, and thermal conductivity due to their many advantages. The carbon material has low density, high specific modulus and specific strength and small vibration attenuation rate, and becomes the first choice of aerospace materials. Although the carbon material has good high temperature resistance, the pure carbon material product can work at the high temperature of 3000 ℃ in a vacuum environment, but the oxidation resistance of the carbon material is poor, and the carbon material product can generate chemical reaction with oxygen in the air of more than 400 ℃ to cause the failure of the carbon material product. Therefore, the preparation of the oxidation resistant coating is an effective way for preventing oxidation of the carbon material.

With the increasing use of carbon materials, carbon material products must have a wide temperature range of oxidation resistance. Among the oxidation resistant coatings, the ultra high temperature ceramic boride HfB₂The composite coating formed by the SiC can generate multiple components with different melting points and protection temperature range during oxidationThe product is oxidized, and a layer of compact and stable Hf-Si-O composite glass phase capable of self-healing and sealing defects is formed, so that the great wide-temperature-range oxidation defense potential is presented. Ren et al reported that HfB 2-SiC/SiC oxidation resistant coating is prepared on the surface of C/C composite material by using in-situ reaction method in "Ultra-high partial ceramic HfB2-SiC coating for oxidation protection of SiC-coated carbon/carbon composites", and under the effective protection of the coating, the mass loss of the sample after 1773K oxidation for 265 hours is only 0.41 multiplied by 10⁻²g²/cm². "Talmy et al at High-temperature chemistry and oxidation of ZrB₂ceramics containing SiC, Si₃N₄, Ta₅Si₃, and TaSi₂"the presence of Ta oxide in silicate glasses is reported to contribute to the stability of the glass phase and thus to the high temperature oxidation resistance of the ceramic.

Currently, HfB is prepared₂The process of-SiC coating mainly comprises embedding method, in-situ reaction method, slurry method, liquid phase sintering method, plasma spraying method and the like. The method mainly adopts a high-temperature pressureless sintering mode to obtain the coating. Too high sintering temperature can cause excessive growth of crystal grains and reinforcing phases and increase coating defects, thereby affecting the antioxidation effect and increasing the energy consumption and the production cost. The pressureless sintering mode is not favorable for obtaining a high-density coating, and the combination of the reinforcing phase and the coating is influenced.

In recent years, Spark Plasma Sintering (SPS) has attracted attention as a new low-temperature hot-pressing rapid sintering technique. The technology can prepare the high-density material by sintering at low temperature in a pressure increasing mode, reduces coating defects, improves density, enhances bonding strength, and has controllable coating thickness, components and content. For this purpose, Zhang et al are in "Reaction synthesis of spark plasma intercalated MoSi₂-B₄The preparation of highly dense MoSi by sintering at low temperature using SPS method was reported in C coatings for oxidation protection of Nb alloy₂-B₄And C, an oxidation resistant coating, wherein the coating shows a good microstructure and oxidation resistance. At present, the discharge plasma sintering method is not applied to HfB₂In the preparation of the-SiC oxidation resistant coating, the inventor finds out through experiments that the high-density and low-defect HfB can be prepared by rapid sintering at lower temperature by using the spark plasma sintering method₂-SiC oxidation resistant coating.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a method for preparing HfB on the surface of a carbon-based material at a lower sintering temperature₂The preparation method of the-SiC oxidation resistant coating is simple and can realize the HfB₂The control of the components, thickness, compactness and bonding strength with the carbon matrix of the SiC coating enhances the oxidation resistance of the carbon matrix.

The technical scheme adopted by the invention is as follows: HfB on surface of carbon-based material₂The preparation method of the-SiC oxidation resistant coating comprises the steps of weighing HfB with a certain proportion₂Mixing the SiC powder uniformly, wrapping the carbon substrate with the uniformly mixed powder in a graphite mould, and synthesizing HfB on the surface of the carbon substrate by adopting a discharge plasma sintering method₂-SiC oxidation resistant coating.

Further, the preparation method comprises the following specific steps:

(1) surface treatment of the carbon substrate: sanding a carbon matrix (graphite or C/C composite material) by using sand paper with different roughness, then cleaning by using alcohol, and finally airing to be dry;

(2) mixing materials: firstly, respectively weighing HfB with certain mass fraction₂5 to 95 percent of powder material and 5 to 95 percent of SiC powder material with the purity of more than or equal to 99.0 percent and the granularity of less than or equal to 50 mu m, and then the HfB is prepared by ball milling and uniformly mixing₂The rotation speed of a ball mill is 50-1000r/min, and the ball milling time is 0.5-10 hours;

(3) die filling: using HfB obtained in the step (2) in a graphite mold₂Wrapping the carbon substrate treated in the step (1) with-SiC composite powder, wherein HfB is covered on the periphery of the substrate₂The thickness of the-SiC composite powder is about 0.1 to 3 times of the thickness of the carbon matrix;

(4) spark plasma sintering: putting the mould filled with the sample into a spark plasma sintering furnace for sinteringTreating at 1900 deg.C with sintering temperature of 1200-₂-SiC oxidation resistant coating.

Compared with the prior art, the invention has the beneficial effects that:

1. HfB prepared on surface of carbon-based material by using discharge plasma sintering method₂the-SiC oxidation resistant coating and the carbon material matrix have high bonding strength, are not easy to peel off in the service process, and the service life of the coating is prolonged.

2. HfB prepared on surface of carbon-based material by using discharge plasma sintering method₂the-SiC oxidation resistant coating has good compactness and uniform phase distribution and coating thickness.

3. HfB prepared on surface of carbon-based material by using discharge plasma sintering method₂the-SiC oxidation resistant coating can regulate and control the content and the thickness of components.

4. HfB prepared on surface of carbon-based material by using discharge plasma sintering method₂the-SiC oxidation resistant coating has low sintering temperature and short sintering time, and can effectively inhibit the growth of crystal grains.

5. The problems that phase components and the thickness of the coating are difficult to control and the density is low in other pressureless sintering methods for the surface of the carbon material are solved, and the purpose of the invention is achieved.

6. The method is simple and practical, the oxidation resistance of the carbon substrate is greatly improved, and the coating has excellent comprehensive performance and wide development prospect.

Drawings

FIG. 1 shows 60% HfB on the surface of a carbon substrate prepared in example 1 of the present invention₂-surface XRD pattern of 40% SiC oxidation resistant coating;

FIG. 2 shows 60% HfB on the surface of the carbon substrate prepared in example 1 of the present invention₂-cross-sectional SEM images of 40% SiC oxidation resistant coating;

FIG. 3 shows that 70% HfB is on the surface of the carbon substrate prepared in example 2 of the present invention₂-surface XRD pattern of 30% SiC oxidation resistant coating;

FIG. 4 shows that 70% HfB is on the surface of the carbon substrate prepared in example 2 of the present invention₂-30% SiC oxidation resistant coatingCross-sectional SEM images of;

FIG. 5 shows 80% HfB on the surface of carbon substrate prepared in example 3 of the present invention₂-surface XRD pattern of 20% SiC oxidation resistant coating;

FIG. 6 shows 80% HfB on the surface of carbon substrate prepared in example 3 of the present invention₂-cross-sectional SEM images of 20% SiC oxidation resistant coating;

wherein: 1-HfB₂2-SiC, 3-carbon matrix.

Detailed Description

For the purpose of enhancing the understanding of the present invention, the present invention will be further explained with reference to the accompanying drawings and examples, which are only for the purpose of explaining the present invention and do not limit the scope of the present invention.