碳化硅零件氧化辅助抛光加工机理与关键工艺研究

Silicon carbide has been widely used in the industrial fields for its excellent physical and chemical properties, and oxidation-assisted polishing is an important machining technique for obtaining silicon carbide parts with high precision. Up to now, amazing productions have been achieved in the experimental research on oxidation-assisted polishing of silicon carbide in both domestic and abroad, and atomically ultra-smooth single crystal silicon carbide surface and high precision reaction sintered silicon carbide surface had been obtained. However, the research on machining mechanism in oxidation-assisted polishing of silicon carbide parts has not gained breakthrough, and the selection of process parameters is devoid of effective theoretically support, which limit the application of oxidation-assisted polishing technique in the ultra-precision machining of silicon carbide parts. This project takes the research on machining program of oxidation-assisted polishing of silicon carbide parts as section start, and the model for oxidation of silicon carbide and model for polishing of oxide layer are constructed based on First Principle calculation and Molecular Dynamics simulation. The research on machining mechanism is obtained through the combination of theoretical investigation and experimental analysis. The optimization model based on Artificial Neural Network is built, which takes the process parameters as object and takes the material removal rate and surface property as aim. The optimization of process parameters is obtained by the combination of theoretical modeling and experimental validation. Innovatory research productions on machining mechanism and pivotal process in the oxidation-assisted polishing of silicon carbide parts can be obtained through this project, which will promote the process level in ultra-precision machining of silicon carbide parts.

碳化硅以其卓越的物理化学性能在工业领域中得到广泛应用，氧化辅助抛光是获得高精度碳化硅零件的重要加工技术。目前，国内外在碳化硅氧化辅助抛光的实验研究方面取得了可喜成果，能够获得原子级超光滑单晶碳化硅表面和高精度烧结碳化硅表面。但是，碳化硅零件氧化辅助抛光加工机理的研究尚未取得突破进展，对工艺参数的选择也缺乏有效的理论支撑，限制了氧化辅助抛光技术在碳化硅零件超精密加工中的应用。本项目拟以碳化硅零件氧化辅助抛光的加工过程研究为切入点，构建基于第一性原理计算和分子动力学模拟的碳化硅氧化模型和氧化层抛光模型，以理论研究与实验分析相结合的方式研究加工机理；构建以工艺参数为对象、以材料去除效率和表面质量为目标的人工神经网络优化模型，通过理论建模与实验验证相结合的方式实现工艺参数优化。本项目有望在碳化硅零件氧化辅助抛光加工机理与关键工艺研究上取得创新性研究成果，促进碳化硅零件超精密加工工艺水平的提升。

碳化硅以其卓越的物理化学性能在工业领域中得到广泛应用，氧化辅助抛光是获得高精度碳化硅零件的重要加工技术。.本课题在分子动力学模拟中构建了碳化硅的理论模型，研究了热氧化和等离子体氧化过程的氧化机理，探讨了生成氧化物的物理化学性质，利用电化学理论分析了阳极氧化过程，并利用扫描白光干涉仪、扫描电子显微镜开展了实验验证。研究结果表明：热氧化过程的氧化速度排序为无定形硅>硅面β-SiC>>碳面β-SiC；等离子体氧化过程中由于多重效应叠加导致各成分氧化速度基本均衡；阳极氧化过程中氧化速度与电流分布相关；氧化物的物理化学性质与SiO2基本一致，其抛光过程符合一般化学机械抛光机理；β-SiC在等离子体氧化和热氧化过程中存在取向性。对氧化辅助抛光碳化硅零件加工机理的研究，为提升其超精密加工工艺水平奠定了理论基础。.构建了基于人工神经网络的工艺参数优化模型，针对等离子体氧化辅助抛光、热氧化辅助抛光和阳极氧化辅助抛光的典型工艺参数开展优化，并利用扫描白光干涉仪、原子力显微镜、扫描白光干涉仪开展了实验验证。研究结果表明：通过控制抛光液浓度、旋转速度、进给速度、负载等工艺参数，等离子体氧化辅助抛光烧结碳化硅可以获得表面粗糙度rms为0.629nm的超光滑表面，热氧化辅助抛光烧结碳化硅可以获得表面粗糙度rms为0.920nm的超光滑表面，阳极氧化辅助抛光烧结碳化硅可以获得0.318μm/min的高材料去除效率，加工过程中获得高材料去除效率和高表面质量的关键是获得与氧化速度相匹配的抛光速度。对氧化辅助抛光碳化硅零件工艺参数的优化，为促进碳化硅零件在工业领域的应用提供了技术支持。.研究提升了氧化辅助抛光超精密加工工艺水平，促进了碳化硅在国民经济各领域的应用，完善了超精密加工工艺研究团队建设，通过研究生培养充实了团队，促进了研究的可持续发展。

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