钛渣熔体结构及传输性质分子动力学模拟研究进展

高品位钛渣(TiO2含量≥90%)的高效制备不仅是高品质钛产品生产的关键,而且已成为我国钛冶金行业发展的迫切需要。钛铁矿还原熔炼过程钛渣熔体传输性质的调控是实现高品位钛渣高效制备的关键。国内外学者采用分子动力学模拟的方法,开展钛渣熔体结构演变及传输性质的研究,取得了显著的进展,证实了分子动力学模拟的方法在钛渣熔体研究中的有效性。分子动力学模拟的方法在研究钛渣熔体结构和性质方面具有显著的优势,不但能考察钛渣熔体结构参数、传输性质及相关微观细节,而且不受试验条件（高温、高腐蚀性、高化学活性）的限制。通过分子动力学模拟能够获取钛渣熔体丰富的结构信息和重要的传输性质,避免了钛渣熔体结构及物理性质试验测试中存在的难题。最后,结合冶金熔体成分和结构的复杂性,总结存在的问题,对分子动力学模拟在熔体结构及传输性质研究中的应用进行了展望。     

金属间化合物Al3Fe熔体结构的计算机模拟

本文利用ＴＢ模型对Ａｌ３Ｆｅ熔体结构进行了分子动力学计算机模拟，详细考察了在快速弟固条件下Ａｌ３Ｆｅ熔体结构的温度变化特征，计算了不同温度下的偶分布函数，分析了在快速凝固条件下Ａｌ３Ｆｅ合金熔体的结构特点。     

Electrode Process of Y~(3 )Ion on Molybdenum and Nickel Electrodes in YCl_3-NaCl-KCl Melt

The electrode process of Y~(3 )ion on molybdenum and nickel electrodes has been studied by cyclicvoltammetry and chronopotentiometry in the YCl_3-NaCl-KCl melt.The overall charge transfer process is atwo-step reaction:Y~(3 ) e=Y~(2 );Y~(2 ) 2e=Y.Yttrium reduced on the nickel electrode can form a series of Ni-Yalloys.X-ray diffraction analysis was employed to determine the alloy compositions formed under different con-ditions.     

Influence of Solid-liquid Interaction and Temperature on the Dynamic Dewetting of a Thin Polymer Film:A Molecular Dynamics Study

Coarse-grained molecular dynamics simulations were carried out to investigate the dewetting behavior of a polymer thin film on partial wetting solid surface at the early stage of the dewetting process. Spontaneous dewetting is initiated by removing a band of strip from both the ends of the liquid polymer film which has achieved equilibrium.The solid-liquid interaction and temperature were varied to show their influence on the dewetting dynamics during dewetting as well as the shape evolution of the liquid polymer film. As is consistent with the results obtained in previous researches, the liquid film recedes at a constant speed initially with different solid-liquid couplings and temperatures. Furthermore, smaller coupling parameters or higher temperatures tend to accelerate the recession speed of the liquid film and shorten the constant-speed recession duration. Obvious rims were not always observed. Both coupling parameter and temperature can influence the emergence of the rims.     

NiAl应力诱发马氏体相变的分子动力学模拟

利用ＮｉＡｌ合金的嵌入原子势，通过分子动力学模拟方法研究了标准化学计量比ＮｉＡｌ合金中应力诱发马氏体相变的微观机理。系统径向分布函数的变化表明，模拟中发生了Ｂ２结构奥氏体逐渐转变为四方Ｌ１０结构马氏体的相变，分析了马氏体形核和长大过程中系统微观结构的变化规律。通过分析形核前后系统应变的变化过程，探讨了应力诱发马氏体形核的微观机理。     

Dynamics Analysis and Simulation of the Swiss Lever Escapement Mechanism

Swiss lever escapement is almost always used in all mechanical watches, which is one of the most critical com- ponents in a mechanical watch.However, its dynamics has not been fully studied.This paper presents a method for dy- namics analysis and simulation of the Swiss level escapement.First, the Swiss lever escapement mechanism is introduced and its motion in a half-period is divided into four sections.Then the dynamics model is developed using impulsive differ- ential equations and the simulation result is obtained by MATLAB.A watch called Seiko7009a is taken as an exainple.The simulation result shows the dynamic behavior in terms of the relationship among displacement, angle and time.The spring constant and balance wheel inertia that governed the timekeeping accuracy are also discussed.     

铝熔体中的氢的研究

介绍了铝熔体中的氢的来源及其存在形态,分析了铝液吸氢的过程。讨论了铝液中氢的溶解度及其影响因素。分析了熔体中的三种三氧化铝夹杂对氢含量的影响。研究了除氢的动力学过程以及影响除氢速度的因素。     

B2O3对含钛高炉渣熔体微观结构与输运性质的影响

为高效利用含钛高炉渣中钛元素,采用分子动力学模拟方法研究B2O3含量对CaO-SiO2-B2O3-TiO2系高炉渣微观结构和输运性质的影响。结果表明：B2O3的含量4%时,B—O、Si—O、Ti—O和Ca—O的键长分别为1.34、1.62、1.95和2.24 ?。渣中存在[SiO4]四面体、[BO3]三角体和[TiO6]八面体稳定结构单元。体系中加入B2O3含量并不会改变O—Si—O、O—B—O和O—Ti—O键角分布情况。随着B2O3的加入,Si—O—Si和B—O—B键角分别从156.12°和148.43°增大到158.17°和157.08°,大部分Ti-O-Ti键角分布在100.48°,小部分Ti—O—Ti键角从140.17°减小到135.53°。随着B2O3含量的增加,B—O—M(Ca、Si、B和Ti)氧连接占比增多,熔体中高配位结构解聚为低配位结构,体系整体聚合度降低,各离子自扩散系数均增大,熔体黏度从0.183 Pa?s降低到0.140 Pa?s。     

熔体测温技术

本文主要是从接触式测温技术与非接触式测温技术这两个方面介绍了国内外铜熔体测温技术的现状与发展趋势,指出解决接触式测温技术的关键是优良的套管材料。     

Diffusion and Adsorption of Benzene and Propylene in MFI, MWW and BEA Zeolites:Molecular Dynamics and Grand Canonical Monte Carlo Simulations

The diffusion and adsorption behaviors of benzene and propylene in zeolites MFI, MWW and BEA have been studied by molecular dynamics(MD) and grand canonical Monte Carlo(GCMC) simulations. The diffusion coefficients of benzene and propylene in MFI, MWW and BEA zeolites were calculated by simulating the mean-square displacements(MSD) at 298 and 600 K. Benzene and propylene showed the different adsorption rules in the channels of the three zeolites. For propylene, the molecular loadings decreased in the order: BEA(linear channel)＞BEA (tortuous channel)＞MFI(linear channel)＞MWW(12-membered rings, 12MR channel)＞MFI(tortuous channel)＞MWW (10-membered rings, 10MR channel); for benzene, the molecular loadings decreased in the order: BEA(linear channel)＞BEA(tortuous channel)＞MWW(12MR channel)＞MFI(linear channel)＞MFI(tortuous channel)＞MWW(10MR channel). Besides, the adsorption isotherms of benzene and propylene in the three zeolites at 298 and 443 K were simulated. The results show that the different factors influenced the molecular adsorption at various temperatures and pressures, leading to the different rules for the adsorption of benzene and propylene molecules in the zeolites. At a low pressure, the unfavorable energy would make the loadings of propylene lower than those of benzene. When pressure was higher than 0.25 kPa, the adsorption of benzene in MFI would nearly reach saturation.     

氧化物复合脱铜剂钢液脱铜

实验研究了1600℃时,不同C-ZnO配比条件下,Al₂O₃-ZnO-C及Al₂O₃-ZnO-Al复合脱铜剂的钢液脱铜效果.对氧化物复合脱铜剂的脱铜原理,脱铜步骤及提高脱铜效率的因素进行了分析讨论.     

铁酸盐粘结相熔化速率及对烧结强度的影响

 考察了添加SiO2和Al2O3对铁酸钙（铁酸一钙CaO·Fe2O3和二铁酸钙CaO·2Fe2O3）熔化速率的影响。同时考察了铁酸盐添加SiO2和Al2O3对以其为粘结相的烧结试样强度的影响。试验结果表明：铁酸一钙中添加SiO2和Al2O3促进了熔体的形成;而二铁酸钙添加SiO2和Al2O3则抑制了其熔体的形成。在CF中添加SiO2和Al2O3对烧结试样强度的影响中,当添加w(SiO2)=2%和w(Al2O3)=4%时获得相对较大的烧结强度;而在CF2中添加SiO2和Al2O3则对烧结试样强度有不利影响。     

喂丝法钢液脱铜

提出了用喂丝法向钢液中插入铵盐或氨基化合物的脱铜方法.在常压下,Ar气氛中,向钢液中分别加入NH₄Cl和NH₂CONK₂把约300g钢水含铜量从0.6%降至0.47%～0.5%,仅用脱铜剂2～4g.氯化铵有氯化和铵分解的双重脱铜作用,比尿素脱铜效果更好.     

Calculation Model for Surface Tension of Slag Melt

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铝及其合金熔体净化技术的实践

本文分析了铝熔体中氢与Al2O3夹杂物的来源及相互作用．提出了铝熔体净化必须“除气除渣同时进行，除渣是除气的前提”的原则．介绍了气体 精炼剂-气体-过滤综台净化技术．及提高铝熔体净化效果的新技术途径。     

ZL205A铝合金熔体净化效果分析

介绍了铝熔体中夹杂物与气体的主要存在形态及其相互作用。结合生产应用实践．简述了ZL205A铝合金熔体的净化工艺及其影响因素，提出铝液的净化应以除渣为主．去气为辅。     

乙酰胺-尿素-NaBr熔体中Gd-Co合金膜的电沉积研究

利用循环伏安法和恒电位电解法探讨了353K时乙酰胺．尿素(26．7%，质量分数)-NaBr(12．0％，质量分数)熔体体系中Gd-Co合金膜的电化学制备。研究了沉积时的电流密度、时间、温度以及Gd(Ⅲ)/Co(Ⅱ)浓度比对沉积膜质量的影响。结果表明，在乙酰胺-尿素(26．7％)-NaBr(12．0％)熔体中，控制恰当的体系组成和沉积条件，均可得到表面均匀、附着力强、有金属光泽的灰黑色非晶态Gd-Co合金膜，其中Gd的质量分数可达4．92％～85．89％，所得到的沉积膜通过SEM，EDS和XRD进行了分析。     

泡沫Al-6Si合金的制备工艺研究

采用熔体发泡法制备泡沫铝硅合金。研究发泡剂添加量、粘度、加热温度、搅拌速度等对孔隙率及孔结构的影响 ,并通过对发泡介质TiH2 的预处理 ,研究TiH2 形成表层氧化物对延缓其在熔体中的分解及发泡过程的作用。考察制备泡沫铝材料实验的再现性 ,从而确定最佳工艺参数。研究表明 ,以TiH2 为发泡介质 ,采用熔体发泡制备孔隙结构均匀 ,孔隙率为 60 %～ 80 %的泡沫铝硅合金的最佳工艺条件是 :加热温度为 610～ 63 0℃ ,TiH2 含量为 1.2 %～ 1.4%,金属钙加入量为 1.5 %,增粘搅拌时间为 4～ 5min ,搅拌速度约为 80 0r·min- 1 ;发泡介质分散搅拌时间为 3 0～ 40s,搅拌速度约为 2 0 0 0r·min- 1 。     

Fe C N金属熔体作用浓度计算模型

 实验在MoSi2电阻炉内用饱和浓度法测试了Fe C N体系氮的浓度和活度,并根据含化合物的金属熔体结构的共存理论模型,推导了Fe C N金属熔体作用浓度计算模型。实验测得1 485 ℃碳饱和的Fe C N熔体中在氮分压01 MPa时氮的溶解度为0006 5%,并且计算的作用浓度与相应的实测活度相符合,从而证明所得模型可以反映Fe C N金属熔体的结构本质,由模型得出金属熔体高碳含量有利于脱氮。