The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform

Dongming Guo - One of the best experts on this subject based on the ideXlab platform.

  • insight into the mechanism of low friction and wear during the chemical mechanical Polishing process of diamond a reactive molecular dynamics simulation
    Tribology International, 2020
    Co-Authors: Song Yuan, Xiaoguang Guo, Junxin Huang, Yonjun Gou, Zhuji Jin, Renke Kang, Dongming Guo
    Abstract:

    Abstract Chemical mechanical Polishing(CMP) is an important method to achieve ultra-precision machining of diamond. However, the friction mechanism during CMP is not well understood due to a lack of information regarding the interface. Here, reactive molecular dynamics simulation was utilized to elucidate the friction behavior under different pressures and flow fates of Polishing Slurry. Simulation results indicated that pressure could accelerate the passivation of surface, Pauli repulsion between abrasive and substrate could withstand the applied load and prevent the two surfaces from reaching the C–C interaction range. The number of C atoms removed and the subsurface damage of substrate are the function of flow fate and pressure. This provides a theoretical support for the ultra-precision and low-damage machining of diamond.

  • development of a novel chemical mechanical Polishing Slurry and its Polishing mechanisms on a nickel alloy
    Applied Surface Science, 2020
    Co-Authors: Zhenyu Zhang, Longxing Liao, Xinze Wang, Wenxiang Xie, Dongming Guo
    Abstract:

    Abstract Conventional chemical mechanical Polishing (CMP) slurries of pure nickel (Ni) and its alloys usually consist of toxic and corrosive acids, which is dangerous and contaminative to the operators and environment. It is a big challenge to develop a novel environment friendly CMP Slurry for Ni alloys. In this study, a novel environment friendly CMP Slurry was developed, containing of silica, hydrogen peroxide (H2O2), malic acid and deionized water. The surface roughness Ra, and peak-to-valley (PV) values are 0.44, and 4.49 nm, respectively with an area of 71 × 53 μm2. To the best of our knowledge, surface roughness in this work is the lowest for pure Ni and its alloys at a scan area of 71 × 53 μm2. The CMP mechanisms are elucidated by electrochemical, X-ray photoelectron spectroscopy, and infrared measurements. Firstly, H2O2 dominated the oxidation process in CMP, forming oxides of nickel (Ni), chromium (Cr), and molybdenum (Mo) on the surface of Ni alloy. Then, the Ni oxides were dissolved by hydrogen (H) ions. The oxides of Cr and Mo were stable in malic acid. Chelating formulas are proposed between malic acid and Ni ions. Finally, the passivated film was removed by the Polishing pad.

  • Environment friendly chemical mechanical Polishing of copper
    Applied Surface Science, 2019
    Co-Authors: Zhenyu Zhang, Junfeng Cui, Jiabo Zhang, Dongdong Liu, Dongming Guo
    Abstract:

    Abstract Chemical mechanical Polishing Slurry of copper usually contains more than four compositions, in which strong acids, alkalis or hazardous chemicals are normally employed. With these slurries, surface roughness less than 1 nm is difficult to obtain on the surface of copper after chemical mechanical Polishing. It is a challenge to develop a kind of novel chemical mechanical Polishing Slurry for copper including three environment friendly compositions. In this study, a kind of novel chemical mechanical Polishing Slurry is developed consisting of silica, hydrogen peroxide and chitosan oligosaccharide, where all the three compositions are environment friendly. After chemical mechanical Polishing, surface roughness Ra and peak-to-valley values are 0.444 and 5.468 nm respectively. Chemical mechanical Polishing mechanism is elucidated by infrared and X-ray photoelectron spectra and electrochemical measurements. Firstly, Cu surface is oxidized by hydrogen peroxide, forming CuO and Cu(OH)2. Then, CuO and Cu(OH)2 are dissolved by H+ ions released by the ionization of chitosan oligosaccharide. Subsequently, Cu2+ ions are chelated by chitosan oligosaccharide molecules. Finally, the adsorbed layer is removed by silica nanospheres, generating ultra-smooth surface of copper. The findings propose a new route for fabrication devices of copper and other transition metals used in integrated circuits, graphene, transformers, batteries and electronics industries.

Fu Y - One of the best experts on this subject based on the ideXlab platform.

  • A study of computer controlled ultra-precision Polishing of silicon carbide reflecting lenses for enhancing surface roughness
    Scientific.Net, 2015
    Co-Authors: Li Z., Wb Lee, Cf Cheung, Fu Y
    Abstract:

    5th International Conference on Asian Society for Precision Engineering and Nanotechnology, ASPEN 2013, Taipei, 12-15 November 2013Reflecting lens is an important component of optical systems, such as high-resolution cameras, large space telescopes and meteorological satellites etc. Among the lens materials, Silicon Carbide (SiC) has attracted a lot of attention as an important optical material because of its excellent mechanical and physical properties. Apart from the form accuracy, the attainment of a consistently high optical quality in Polishing SiC is still of a concern. There are advanced ultra-precision Polishing machines that can correct geometrical errors and surface finish of the workpiece. These include surface roughness and waviness. However, the hardness of SiC material itself put an challenge for Polishing process. In this paper, A computer controlled ultra-precision Polishing (CCUP) method based on mechanical Polishing is used to produce the SiC lens. Experiments are being designed on a 7-axis ultra precision Polishing machine (Zeeko IRP200). As it is difficult to find out Slurry which is harder than SiC so that the conventional Polishing Slurry is be used. It provides a nice consequence that it also efficient when the polish powder is softer than the machined materials. The tool pressure, Polishing head speed and the feed rate are varied and optimized to obtain the best reflectivity of the lens being polished. A pilot experiment will be conducted for the corrective Polishing for the form error of the optical surface made of SiC. The result from the study will provide an important means to optimize the process for machining SiC reflective lens using the CCUP process.Department of Industrial and Systems EngineeringRefereed conference pape

  • A study of computer controlled ultra-precision Polishing of silicon carbide reflecting lenses for enhancing surface roughness
    'Trans Tech Publications Ltd.', 2015
    Co-Authors: Li Z., Wb Lee, Cf Cheung, Fu Y
    Abstract:

    5th International Conference on Asian Society for Precision Engineering and Nanotechnology, ASPEN 2013, Taipei, 12-15 November 2013Reflecting lens is an important component of optical systems, such as high-resolution cameras, large space telescopes and meteorological satellites etc. Among the lens materials, Silicon Carbide (SiC) has attracted a lot of attention as an important optical material because of its excellent mechanical and physical properties. Apart from the form accuracy, the attainment of a consistently high optical quality in Polishing SiC is still of a concern. There are advanced ultra-precision Polishing machines that can correct geometrical errors and surface finish of the workpiece. These include surface roughness and waviness. However, the hardness of SiC material itself put an challenge for Polishing process. In this paper, A computer controlled ultra-precision Polishing (CCUP) method based on mechanical Polishing is used to produce the SiC lens. Experiments are being designed on a 7-axis ultra precision Polishing machine (Zeeko IRP200). As it is difficult to find out Slurry which is harder than SiC so that the conventional Polishing Slurry is be used. It provides a nice consequence that it also efficient when the polish powder is softer than the machined materials. The tool pressure, Polishing head speed and the feed rate are varied and optimized to obtain the best reflectivity of the lens being polished. A pilot experiment will be conducted for the corrective Polishing for the form error of the optical surface made of SiC. The result from the study will provide an important means to optimize the process for machining SiC reflective lens using the CCUP process.Department of Industrial and Systems Engineering2014-2015 > Academic research: refereed > Refereed conference pape

Zhenyu Zhang - One of the best experts on this subject based on the ideXlab platform.

  • development of a novel chemical mechanical Polishing Slurry and its Polishing mechanisms on a nickel alloy
    Applied Surface Science, 2020
    Co-Authors: Zhenyu Zhang, Longxing Liao, Xinze Wang, Wenxiang Xie, Dongming Guo
    Abstract:

    Abstract Conventional chemical mechanical Polishing (CMP) slurries of pure nickel (Ni) and its alloys usually consist of toxic and corrosive acids, which is dangerous and contaminative to the operators and environment. It is a big challenge to develop a novel environment friendly CMP Slurry for Ni alloys. In this study, a novel environment friendly CMP Slurry was developed, containing of silica, hydrogen peroxide (H2O2), malic acid and deionized water. The surface roughness Ra, and peak-to-valley (PV) values are 0.44, and 4.49 nm, respectively with an area of 71 × 53 μm2. To the best of our knowledge, surface roughness in this work is the lowest for pure Ni and its alloys at a scan area of 71 × 53 μm2. The CMP mechanisms are elucidated by electrochemical, X-ray photoelectron spectroscopy, and infrared measurements. Firstly, H2O2 dominated the oxidation process in CMP, forming oxides of nickel (Ni), chromium (Cr), and molybdenum (Mo) on the surface of Ni alloy. Then, the Ni oxides were dissolved by hydrogen (H) ions. The oxides of Cr and Mo were stable in malic acid. Chelating formulas are proposed between malic acid and Ni ions. Finally, the passivated film was removed by the Polishing pad.

  • Environment friendly chemical mechanical Polishing of copper
    Applied Surface Science, 2019
    Co-Authors: Zhenyu Zhang, Junfeng Cui, Jiabo Zhang, Dongdong Liu, Dongming Guo
    Abstract:

    Abstract Chemical mechanical Polishing Slurry of copper usually contains more than four compositions, in which strong acids, alkalis or hazardous chemicals are normally employed. With these slurries, surface roughness less than 1 nm is difficult to obtain on the surface of copper after chemical mechanical Polishing. It is a challenge to develop a kind of novel chemical mechanical Polishing Slurry for copper including three environment friendly compositions. In this study, a kind of novel chemical mechanical Polishing Slurry is developed consisting of silica, hydrogen peroxide and chitosan oligosaccharide, where all the three compositions are environment friendly. After chemical mechanical Polishing, surface roughness Ra and peak-to-valley values are 0.444 and 5.468 nm respectively. Chemical mechanical Polishing mechanism is elucidated by infrared and X-ray photoelectron spectra and electrochemical measurements. Firstly, Cu surface is oxidized by hydrogen peroxide, forming CuO and Cu(OH)2. Then, CuO and Cu(OH)2 are dissolved by H+ ions released by the ionization of chitosan oligosaccharide. Subsequently, Cu2+ ions are chelated by chitosan oligosaccharide molecules. Finally, the adsorbed layer is removed by silica nanospheres, generating ultra-smooth surface of copper. The findings propose a new route for fabrication devices of copper and other transition metals used in integrated circuits, graphene, transformers, batteries and electronics industries.

Li Z. - One of the best experts on this subject based on the ideXlab platform.

  • A study of computer controlled ultra-precision Polishing of silicon carbide reflecting lenses for enhancing surface roughness
    Scientific.Net, 2015
    Co-Authors: Li Z., Wb Lee, Cf Cheung, Fu Y
    Abstract:

    5th International Conference on Asian Society for Precision Engineering and Nanotechnology, ASPEN 2013, Taipei, 12-15 November 2013Reflecting lens is an important component of optical systems, such as high-resolution cameras, large space telescopes and meteorological satellites etc. Among the lens materials, Silicon Carbide (SiC) has attracted a lot of attention as an important optical material because of its excellent mechanical and physical properties. Apart from the form accuracy, the attainment of a consistently high optical quality in Polishing SiC is still of a concern. There are advanced ultra-precision Polishing machines that can correct geometrical errors and surface finish of the workpiece. These include surface roughness and waviness. However, the hardness of SiC material itself put an challenge for Polishing process. In this paper, A computer controlled ultra-precision Polishing (CCUP) method based on mechanical Polishing is used to produce the SiC lens. Experiments are being designed on a 7-axis ultra precision Polishing machine (Zeeko IRP200). As it is difficult to find out Slurry which is harder than SiC so that the conventional Polishing Slurry is be used. It provides a nice consequence that it also efficient when the polish powder is softer than the machined materials. The tool pressure, Polishing head speed and the feed rate are varied and optimized to obtain the best reflectivity of the lens being polished. A pilot experiment will be conducted for the corrective Polishing for the form error of the optical surface made of SiC. The result from the study will provide an important means to optimize the process for machining SiC reflective lens using the CCUP process.Department of Industrial and Systems EngineeringRefereed conference pape

  • A study of computer controlled ultra-precision Polishing of silicon carbide reflecting lenses for enhancing surface roughness
    'Trans Tech Publications Ltd.', 2015
    Co-Authors: Li Z., Wb Lee, Cf Cheung, Fu Y
    Abstract:

    5th International Conference on Asian Society for Precision Engineering and Nanotechnology, ASPEN 2013, Taipei, 12-15 November 2013Reflecting lens is an important component of optical systems, such as high-resolution cameras, large space telescopes and meteorological satellites etc. Among the lens materials, Silicon Carbide (SiC) has attracted a lot of attention as an important optical material because of its excellent mechanical and physical properties. Apart from the form accuracy, the attainment of a consistently high optical quality in Polishing SiC is still of a concern. There are advanced ultra-precision Polishing machines that can correct geometrical errors and surface finish of the workpiece. These include surface roughness and waviness. However, the hardness of SiC material itself put an challenge for Polishing process. In this paper, A computer controlled ultra-precision Polishing (CCUP) method based on mechanical Polishing is used to produce the SiC lens. Experiments are being designed on a 7-axis ultra precision Polishing machine (Zeeko IRP200). As it is difficult to find out Slurry which is harder than SiC so that the conventional Polishing Slurry is be used. It provides a nice consequence that it also efficient when the polish powder is softer than the machined materials. The tool pressure, Polishing head speed and the feed rate are varied and optimized to obtain the best reflectivity of the lens being polished. A pilot experiment will be conducted for the corrective Polishing for the form error of the optical surface made of SiC. The result from the study will provide an important means to optimize the process for machining SiC reflective lens using the CCUP process.Department of Industrial and Systems Engineering2014-2015 > Academic research: refereed > Refereed conference pape

Seungmoon Lee - One of the best experts on this subject based on the ideXlab platform.

  • development of a padless ultraprecision Polishing method using electrorheological fluid
    Journal of Materials Processing Technology, 2004
    Co-Authors: Wookbae Kim, Byungkwon Min, Seungmoon Lee
    Abstract:

    Abstract A new kind of Polishing method for mirror surface using the electrorheological (ER) fluid is presented. ER fluid is colloidal suspension and stiffens into semi-solid when subjected to an electric field. In this study, the mixture of the ER fluid and abrasives is used as Polishing Slurry. When the ER fluid is placed at the interface between a part and a moving platen, the friction force increases with the applied voltage. Since the polymeric ER particles separating two surfaces attract neighboring fine abrasives along the electric field across the gap, making the abrasives participate in material removal, they replace roles of pad used in a common mirror Polishing. This paper analyzes the friction characteristics of the ER fluid at the sliding interface experimentally, and the behavior of the ER particles at the interface with and without the application of an electric field is observed optically. In addition, material removal rate of single crystal silicon according to the electric field strength is evaluated using the mixture of the ER fluid and diamond powders for a few conditions of different velocities and normal pressures. At last, average surface roughness of 2.9 nm is obtained as a result of the Polishing of silicon surface whose average roughness is about 50 nm with the 0.25 μm diamond-mixed ER fluid.