孙佳庆,李江涛,张东生,赵红亮,魏庆渤,杨红霞.CH3SiCl3-H2前驱体化学气相沉积法制备SiC涂层[J].表面技术,2023,52(2):289-296, 306.
SUN Jia-qing,LI Jiang-tao,ZHANG Dong-sheng,ZHAO Hong-liang,WEI Qing-bo,YANG Hong-xia.Preparation of SiC Coating from CH3SiCl3-H2 Precursor by Chemical Vapor Deposition[J].Surface Technology,2023,52(2):289-296, 306 |
| CH3SiCl3-H2前驱体化学气相沉积法制备SiC涂层 |
| Preparation of SiC Coating from CH3SiCl3-H2 Precursor by Chemical Vapor Deposition |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.02.027 |
| 中文关键词: CVD SiC涂层 气相组分 沉积速率 组织形貌 |
| 英文关键词:CVD SiC coatings gas-phase species deposition rates microstructure |
| 基金项目: |
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| Author | Institution |
| SUN Jia-qing | Gongyi Van Yihui Composites Material Co., Ltd., Henan Gongyi 451200, China;School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China |
| LI Jiang-tao | Gongyi Van Yihui Composites Material Co., Ltd., Henan Gongyi 451200, China |
| ZHANG Dong-sheng | Gongyi Van Yihui Composites Material Co., Ltd., Henan Gongyi 451200, China |
| ZHAO Hong-liang | School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China |
| WEI Qing-bo | Gongyi Van Yihui Composites Material Co., Ltd., Henan Gongyi 451200, China |
| YANG Hong-xia | Gongyi Van Yihui Composites Material Co., Ltd., Henan Gongyi 451200, China |
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| 中文摘要: |
| 目的 在石墨基座表面制备碳化硅(SiC)涂层，提高其抗氧化性和耐蚀性。方法 采用化学气相沉积(CVD)法在高纯石墨基体表面制备SiC涂层，结合热力学分析、SEM、XRD等分析测试方法，分析了SiC沉积过程中气相平衡组成在不同H2/MTS物质的量比时随温度变化的关系，研究了工艺参数对涂层沉积速率和组织形貌的影响，探讨了SiC涂层择优取向的形成机制。结果 随着沉积温度升高，SiC沉积过程中主要含碳和含硅中间产物发生转变(CH4→C2H2，SiHCl3、SiCl4→SiCl2)。涂层沉积速率随温度升高而快速增大，受表面化学反应控制，此时β-SiC易沿着(111)晶面生长，从而形成<111>择优取向。随着沉积温度升高，涂层平均晶粒尺寸增大，同时晶粒尺寸的差异性增强，导致涂层表面粗糙度增大。当H2/MTS物质的量比较大时，单位体积内的MTS浓度降低，进而导致涂层沉积速率下降;随着H2/MTS物质的量比增大，涂层平均晶粒尺寸减小，同时晶粒尺寸的差异性降低，导致涂层表面粗糙度减小;H2/MTS物质的量比较小时，由于H2含量不足，基体表面C活性位点增多，易使涂层富碳。SEM图显示涂层表面致密，呈由砂砾状晶粒组成的菜花状形貌。结论 沉积温度为1 150 ℃、H2/MTS物质的量比为15时，能够制备出高纯致密、表面粗糙度较小、沉积速率较快的CVD-SiC涂层。 |
| 英文摘要: |
| Graphite substrate is prone to corrosion and oxidation, which severely limits its application. Herein, silicon carbide (SiC) coating is synthesized on graphite substrate by chemical vapor deposition (CVD) to improve the oxidation and corrosion resistance. MTS, as carbon source and silicon source, was brought into the deposition chamber by bubbling H2, and H2 was also used as a diluent gas in the reaction process. The substrate position was 350 mm during the coating preparation process, the deposition pressure was 2 kPa, the deposition temperature was 1 100, 1 150, 1 200 and 1 250 ℃, respectively; the H2/MTS molar ratio was 10, 15, and 20, respectively; the MTS flow rate was 440 g/h, and the deposition time was 3 h. Combined with the thermodynamic analysis, some characterization methods including scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to the relationship between the temperature and the gas phase equilibrium composition at different H2/MTS molar ratios. Then, the effects of process parameters on the deposition rates and microstructures of the coatings were studied. Finally, the formation mechanism of the preferred orientation structure of the SiC coating was further discussed. The results show that the composition of gas-phase species in the deposition process of SiC coating were mainly CH4, SiHCl3 and SiCl4 at low temperature, while SiCl2 and C2H2 at high temperature, which verified that the pyrolysis of MTS firstly produced silicon-/carbon- chlorosilane compounds and alkane compounds, and then formed SiC film. The deposition rates of coatings increased rapidly with the increasing temperature, which were further controlled by the surface chemical reaction. Meanwhile, β-SiC tended to grow along the (111) crystal plane, forming the <111> preferred orientation when the activation energy of the reaction was 207.32 kJ/mol. With the increase of deposition temperature, the tendency of <111> growth direction of grains was gradually enhanced, resulting in enhanced the grain-like growth. Thus, the average grain sizes and the variability of the coatings increased, resulting in the increase of coating roughness. As the H2/MTS ratio increased, the deposition rate decreased due to the reduced MTS concentration. Then, the average grain sizes of the coatings and the variability of the grain sizes decreased, resulting in reduced surface roughness of the coatings. When the molar ratio of H2/MTS was small, the number of C active sites on the surface of the substrate increased due to insufficient H2, resulting in a decrease in the oxidation resistance of the coating. SEM showed that the surface of the coating exhibitted a dense and cauliflower-like morphology composed of gravel-like grains. This was due to the fact that the deposition process of the SiC coating was controlled by the surface chemical reaction. When the deposition temperature was low, and the gas-phase precursor molecules can continuously nucleate on the surface, while the adsorption molecules on the surface had poor migration ability, so cauliflower-like morphology grew in all directions. It is concluded that when the deposition temperature is 1 150 ℃ and the H2/MTS molar ratio is 15, CVD-SiC coatings with high purity and density, low surface roughness can be prepared at a rapid deposition rate. |
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