First-Principles Molecular-Dynamics Simulations of Electrochemical Machining in Ultrapure Water

超纯水中电化学加工的第一性原理分子动力学模拟

• 批准号: 13650117
• 负责人: GOTO Hidekazu
• 金额: $ 1.79万
• 依托单位: Osaka University (2002)Kyoto Institute of Technology (2001)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650117/
• 关键词: first-principles molecular-dynamics simulation; electrochemical machining in ultrapure water; silicon; aluminum; hydroxyl ion; hydrogen ion; etching; anodic oxidation; 酸化反応; 平面波基底; 超純粋電解加工法

Electrochemical machining process in ultrapure water is indnced by chemical reaction between work surface and OH ions which are generated by dissociations of water molecules by catalytic reaction in ultrapure water using catalyst. This method is one of the most ultraclean and ultraprecision machining method which can avoid contaminations of work surfaces by electrolytes, cleaning processes after machining process and waste water. Any metals can be machined in practical velocity except Si and Al since the anodic oxidations occur on their surfaces. In this study, analysis of surface chemical reactions using first-principles molecular-dynamics simulations was performed in order to reveal the chemical reaction processes on the anode and cathode surfaces. The simulation were carried out on the basis of the Kohn-Sham local-density-functional formalism. A plane-wave basis set and a norm-conserving pseudopotential were used. The standard molecular-dynamics method was adopted for the optimization of the ionic system and the preconditioned conjugate-gradient (CG) method for the quenching procedure of the electronic degrees of freedom. We determined the optimized atomic configurations and electronic distributions for H, H_2O and OH chemisorbed Si(001) and Al(001) surfaces. It was confirmed that an H atom reacts with H_2O molecules on the hydrogen-terminated Si(001) surface or Al(001) surface to produce an OH molecule, and chemisorptions of H atoms and OH molecules to the surface atom breaks the back-bonds and the surface atom is etched with forming an SiH_2(OH)_2 or AlH_2OH molecule. From these simulation results, we deduced that the electrochemical machining of Si and Al cathode surface in ultrapure water is possible. Furthermore, machining experiments in which samples act as cathodes have been performed and it was confirmed that both Si and Al are possible to be machined.

超纯水中电化学加工过程是由水分子在超纯水中催化反应离解产生的OH离子与工件表面发生化学反应而诱发的。该方法可以避免电解液、加工后的清洗工序和废水对工件表面的污染，是一种超洁净、超精密的加工方法。除硅和铝外，任何金属都能以实际速度加工，因为它们的表面发生阳极氧化。在本研究中，为了揭示阳极和阴极表面的化学反应过程，采用第一性原理分子动力学模拟对表面化学反应进行了分析。在Kohn-Sham局部密度泛函形式主义的基础上进行了仿真。采用平面波基集和保范赝势。离子体系的优化采用标准分子动力学方法，电子自由度的猝灭采用预条件共轭梯度法。我们确定了H， H_2O和OH化学吸附Si（001）和Al（001）表面的优化原子构型和电子分布。证实了H原子在端氢Si（001）或Al（001）表面与H_2O分子反应生成OH分子，H原子和OH分子在表面原子上的化学吸附使背键断裂，表面原子被蚀刻形成SiH_2(OH)_2或AlH_2OH分子。结果表明，在超纯水中电解加工硅铝阴极表面是可行的。此外，还进行了样品作为阴极的加工实验，证实了Si和Al都可以加工。

项目成果

H.Goto, K.Hirose, I.Kobata, Y.Toma, Y.Mori: "First-principles Molecular-dynamics Simulations of Electrochemical Machining Processes in Ultrapure Water"Proceedings of The 4th Asian Workshop on First-Principles Electronic Structure Calculations. 155-158 (20

H.Goto、K.Hirose、I.Kobata、Y.Toma、Y.Mori：“超纯水中电化学加工过程的第一原理分子动力学模拟”第四届亚洲第一原理电子结构计算研讨会论文集。

H.Goto, K.Hirose, I.Kobata, Y.Toma and Y.Mori: "A Study on Electrochemical Machining Method in Ultrapure Water - Etching Process of Si(001) Surface Atom by Hydroxyl Function -"Journal of the Japan Society for Precision Engineering. 67, 8. 1321-1326 (2001)

H.Goto、K.Hirose、I.Kobata、Y.Toma 和 Y.Mori：“超纯水中电化学加工方法的研究 - 通过羟基功能蚀刻 Si(001) 表面原子的过程 -”日本学会杂志

Y.Mori, H.Goto, K.Hirose, Y.Toma, I.Kobata, K.Morita, H.Uwani and S.Sasaki: "First-Principles Molecular-Dynamics Calculations for Etching Process of Si(001) in Ultrapure Water"Meeting Abstracts of the Physical Society of Japan. 57-1. 844-844 (2002)

Y.Mori、H.Goto、K.Hirose、Y.Toma、I.Kobata、K.Morita、H.Uwani 和 S.Sasaki：“超纯 Si(001) 蚀刻过程的第一原理分子动力学计算

森 勇藏, 後藤英和, 広瀬喜久治, 當間 康, 小畠厳貴, 森田健一: "超純水のみによる電気化学的加工法の研究 -陰極表面における加工現象-"精密工学会2001年度秋季大会学術講演会講演論文集. 225-225 (2001)

Yuzo Mori、Hidekazu Goto、Kikuji Hirose、Yasushi Toma、Genki Obata、Kenichi Morita：“仅使用超纯水的电化学处理的研究 - 阴极表面的处理现象 -” 日本精密工程学会 2001 年秋季会议学术演讲会议第 225-225 号决议（2001 年）。

Y.Mori, H.Goto, K.Hirose, I.Kobata, Y.Toma and T.Nishimura: "A Study on Electrochemical Machining Method in Ultrapure Water - Electrochemical Machining of Cathode Surface -"Journal of the Japan Society for Precision Engineering. 68, 9. 1241-1245 (2002)

Y.Mori、H.Goto、K.Hirose、I.Kobata、Y.Toma 和 T.Nishimura：《超纯水中电化学加工方法的研究 - 阴极表面的电化学加工 -》日本精密工程学会会刊