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61.
纳米金刚石计算机磁头抛光液的研制及应用 总被引:21,自引:0,他引:21
用聚氧乙烯型非离子表面活性剂可有效分散纳米金刚石于油介质中,由此制得了纳米金刚石抛光液,探讨了纳米金刚石的分散机理,认为庞大的亲水性基团聚氧乙烯基象一巨大的屏障膜,使纳米金刚石颗粒在油中相互弹开,削弱颗粒间的相互作用能,阻止了纳米颗粒的重新团聚,从而实现了纳米金刚石在油中的稳定分散.本文研制的纳米金刚石抛光液应用于计算机磁头的精抛光,能降低计算机磁头表面粗糙度50%以上,解决了计算机磁头行业的技术难题.实验结果表明,纳米金刚石是一种理想的计算机磁头抛光材料. 相似文献
62.
Leonard J. Borucki Thomas Witelski Colin Please Peter R. Kramer Donald Schwendeman 《Journal of Engineering Mathematics》2004,50(1):1-24
Statistical models are presented to describe the evolution of the surface roughness of polishing pads during the pad-conditioning process in chemical-mechanical polishing. The models describe the evolution of the surface-height probability-density function of solid pads during fixed height or fixed cut-rate conditioning. An integral equation is derived for the effect of conditioning on a foamed pad in terms of a model for a solid pad. The models that combine wear and conditioning are then discussed for both solid and foamed pads. Models include the dependence of the surface roughness on the shape and density of the cutting tips used in the conditioner and on other operating parameters. Good agreement is found between the model, Monte Carlo simulations and with experimental data. 相似文献
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为深入理解化学机械抛光过程中的摩擦磨损机理,仿真研究了不同工况对抛光作用的影响规律.建立考虑多相流和离散相的三维CFD模型,研究不同工况下晶片和抛光垫间抛光液的速度和压力分布以及抛光磨粒的分布规律.结果表明:膜厚越小,抛光垫和晶片的转速越大,磨粒的分布密度越小.对流体速度和压力分布规律以及磨粒分布特性进行仿真分析,研究抛光过程中磨粒对晶片表面的动压作用过程.用疲劳断裂能量守恒理论,建立可定量分析各种工况下材料去除率的预测模型,采用Matlab软件对去除率模型进行仿真计算,得到不同工况下碳化硅晶片的去除率曲线.结果表明,抛光垫转速越大,膜厚越小,材料去除率越大,但去除率随着抛光的进行呈现减小的趋势.相比抛光垫转速对去除率的影响,膜厚对去除率的影响较小. 相似文献
66.
单晶SiC的化学机械抛光及其增效技术研究进展 总被引:3,自引:0,他引:3
为了解决传统SiC化学机械抛光(CMP)加工效率低的问题,针对单晶SiC表面抛光质量和材料去除率指标,综述了应用传统碱性抛光液、混合磨粒抛光液及含强氧化剂抛光液对单晶SiC进行化学机械抛光的研究现状;为了提高SiC-CMP的化学和机械两方面作用,对SiC-CMP催化辅助增效技术、SiC电化学机械抛光(ECMP)技术、固结磨料抛光、光催化辅助抛光等增效新技术进行了系统综述;对SiC-CMP及其增效技术进行了分析、讨论,指出了当前的研究难点,展望了进一步提高单晶SiC抛光效率的研究方向. 相似文献
67.
M. Hofele J. Schanz A. Roth D.K. Harrison A.K.M. De Silva H. Riegel 《Materialwissenschaft und Werkstofftechnik》2021,52(4):409-432
Laser powder bed fusion is a well-established 3D printing technique for metal alloys, but exhibits a poor surface quality. Laser polishing provides the possibility of a fast contact-free and fully-automatable surface treatment. This paper deals with the experimental investigation of laser polishing of laser powder bed fusion parts made of aluminium AlSi10Mg. Laser polishing is done with a 4 kW solid state disc laser in combination with a multi-axis system and a one dimensional scanner optic. The laser is operated at continuous and pulsed operation mode. The parameter study reveals a high dependency of the achievable roughness on the laser beam intensity, the track and pulse overlap, the energy density and the number of polishing passes and polishing directions. Pulsed laser polishing mode with up to four passes from different directions revealed the lowest surface roughness of 0.14 μm Ra. With respect to the initial average surface roughness of Ra = 8.03 μm a reduction of the surface roughness of greater than 98 % could be achieved. Polishing with continuous laser radiation at one polishing pass resulted in Ra = 0.23 μm at an area rate of 20 cm2/min. Laser polishing using four passes achieved a further improvement up to Ra = 0.14 μm. 相似文献
68.
Tatiya Khamhangdatepon Vut Tongnan Matthew Hartley Thana Sornchamni Nuchanart Siri-Nguan Navadol Laosiripojana Kang Li Unalome Wetwatana Hartley 《International Journal of Hydrogen Energy》2021,46(48):24666-24675
La0·3Sr0·7Co0·7Fe0·3O3 (LSCF3773) was chosen as an oxygen carrier material for synthesis gas production and synthesized using ethylene-diamine-tetra-acetic acid (EDTA) citrate-complexing method. LSCF exhibited a pure cubic structure where 110 and 100 plane diffractions were active for CO2 splitting, while 111 was more favored by H2O splitting. Overall oxygen storage capacity (OSC) of LSCF was 4072 μmol/gcat. During the reduction process, regular cations (Co4+, Fe4+), polaron cations (Co3+, Fe3+) and localized cations (Co2+, Fe2+) were achieved when the LSCF was reduced at 500, 700 and 900 °C, respectively. The strength of the active sites depended on reduction temperatures. An increase in oxidation temperature enhanced H2 production at temperature ranging from 500 °C to 700 °C while effected CO production at 900 °C. H2O and CO2 was competitively split during the oxidation step, especially at 700 °C. The activation energy of each reaction was ordered as; CO2 splitting > H2O splitting > CO2 adsorption, supporting the above evidence where H2 and CO production were found to increase when the operating temperature was increased. 相似文献
69.
The current research is focused on the hydrogen production through a two‐step ZnO/Zn thermochemical water splitting cycle. In the present paper, numerical modeling of the second step is conducted using Computational Fluid Dynamics (CFD)2, where steam reacts with zinc to produce hydrogen. The parametric study shows that the hydrogen yield is relatively insensitive to the steam/zinc molar ratio and inversely proportional to the argon/steam molar ratio. For large argon to steam molar ratios, hydrogen yield is relatively insensitive to the inlet temperature of zinc and steam, and increases marginally with an increase in the argon inlet temperature. Five different reactor configurations were evaluated comprehensively. Among all configurations, a cylindrical reactor with a tangential inlet for argon and zinc, and a radial inlet for steam (both in the bottom plane of the reactor) and a tangential outlet in the top plane of the reactor produced the highest hydrogen yield of 88%. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
70.
Roughness prediction on laser polished surfaces 总被引:1,自引:0,他引:1
E. Ukar A. LamikizS. Martínez I. TaberneroL.N. López de Lacalle 《Journal of Materials Processing Technology》2012,212(6):1305-1313
The paper presents a methodology to predict the surface topography on laser polished surfaces. The method is based on the thermal field prediction generated by the laser. The thermal field is obtained through the differential equation of heat transfer by conduction. The prediction of the resulting topography is based on the filtering of the spatial frequency spectrum of the initial topography which is obtained by FFT analysis. Once the temperature field is obtained, a critical frequency is calculated and a low-pass filter is applied to cut the frequencies higher than the critical one. The resulting surface is reconstructed using the remaining frequencies. The methodology has been tested on a DIN 1.2379 tool steel and the experimental validation shows a relatively good agreement between the predicted and measured values of mean roughness (Ra) and mean roughness depth (Rz), with errors lower than 15% in all the cases. 相似文献