材料期刊网

MULTIPLE-SCATTERING DETERMINATION TO THE LOCAL ADSORPTION GEOMETRY OF SO2/Pd(111)

S.Cao , J.C.Tang , P.Zhu

金属学报(英文版)

We have calculated the sulphur 1s near edge X-roy absorption fine structure (NEX-AFS) spectra of SO2 adsorbed on Pd( 111 ) in terms of the multiple-scattering Cluster(MSC) method. The origin of the resonances in the NEXAFS spectra has been re-xealed. By the MSC calculation and a (DV)-Xα study we have for the first time iden-tiffed two weak features existing in S K-edge NEXAFS of SO2/Pd(111) system, whichare attributed to the interaction between the adsorbate and the substrate. Moreover,MSC calculation together with the reliability factor (R-.factor) analysis are employedto determine the local adsorption structures. These results are broadly in agreementwith those of Fourier-transform analysis of the surface extended X-ray absorption finestructure (SEXAFS).

关键词: multiple-scattering cltster. near edge X-ray absorption fine structure , null

VIM法中采用CaO坩埚对Ni基高温合金脱S的影响

牛建平 , 杨克努 , 管恒荣 , 胡壮麒

机械工程材料 doi:10.3969/j.issn.1000-3738.2002.02.002

研究了使用CaO坩埚在VIM法精炼Ni基高温合金过程中S的变化规律及加Al对脱S的影响.试验表明:当CaO坩埚中的含S量高于液态金属中的含S量时,坩埚中的S将进入金属液中而使液态金属增S.加入0.5%的Al经30min精炼后可以使液态金属中的S含量从30mg/kg降低至小于5mg/kg.对CaO坩埚内壁的XRD及成分分析表明,加Al脱S是由于在CaO坩埚壁和金属液间形成低熔点的具有很强脱S能力的3CaO@Al2O3渣.

关键词: VIM , CaO坩埚 , Ni基高温合金 , 脱S

CaO对气淬钢渣中C2S等温析晶动力学影响规律

张玉柱 , 鲍继伟 , 龙跃 , 邢宏伟

钢铁

用CaO对气淬钢渣进行调质重构,对不同CaO含量的气淬钢渣在不同温度条件下进行恒温热处理,利用金相显微镜和金相分析软件统计分析热处理后渣样中C2S等温析晶行为的规律,采用Arvami等人提出的JMA方程研究CaO对C2S等温析晶动力学的影响规律.结果表明:随着CaO含量的增加,钢渣中C2S结晶量呈现出先增加后减少的趋势,在碱度为3.25,恒温时间为30min时,C2S结晶量达到最大为64.06％.碱度为3.25时,C2S等温析晶活化能最小为-6.36 kJ/mol,此时C2S析晶的能量势垒最小,最有利于C2S析晶.

关键词: 气淬钢渣 , 碱度 , 动力学 , 等温析晶

采用CaO坩埚超纯净熔炼Ni基高温合金

牛建平 , 杨克努 , 孙晓峰 , 于洋 , 管恒荣 , 胡壮麒

机械工程材料 doi:10.3969/j.issn.1000-3738.2001.05.005

研究了CaO坩埚精炼Ni基高温合金的效果，并与MgO坩埚的熔炼效果进行了对比。结果表明：CaO坩埚比MgO坩埚有利于脱O、N；高温高真空下单纯使用CaO坩埚而无碱性渣不能脱S；熔化期对于O、N的脱除十分重要；适量的C的加入有利于脱O。

关键词: 镍基高温合金 , CaO坩埚 , 真空感应熔炼

Desulphurization during VIM Refining Ni-base Superalloy using CaO Crucible

Jianping NIU , Kenu YANG , Tao JIN , Xiaofeng SUN , Hengrong GUAN , Zhuangqi HU

材料科学技术（英文）

The variation of S content during VIM refining Ni-base superalloy using CaO crucible was studied. It was found that the desulphurization process could not be carried out by only using CaO crucible. The role of Al addition to desulphurization was also studied. Combining with the results of XRD and composition analysis of the CaO crucible, the mechanism of desulphurization was proposed. Thermodynamical calculation about the reaction between the interface of CaO crucible and liquid metal has been discussed. This work indicated that under proper refining technology the S content in the liquid Ni-base alloy could be reduced from 3×10-5 to 2×10-6-4×10-6.

关键词: Ni-base superalloy , null , null , null

Desulphurization during VIM refining Ni-base superalloy using CaO crucible

材料科学技术（英文）

The variation of S content during VIM refining Ni-base superalloy using CaO crucible was studied. It was found that the desulphurization process could not be carried out by only using CaO crucible. The role of Al addition to desulphurization was also studied. Combining with the results of XRD and composition analysis of the CaO crucible, the mechanism of desulphurization was proposed. Thermodynamical calculation about the reaction between the interface of CaO crucible and liquid metal has been discussed. This work indicated that under proper refining technology the S content in the liquid Ni-base alloy could be reduced from 3x10(-5) to 2x10(-6)similar to4x10(-6).

关键词: Ni-base superalloy;CaO crucible;VIM;desulphurization;calcium

脱磷渣中磷在CaO固相颗粒中扩散速率研究

彭军 , 刘爽 , 刘丽霞 , 郭永 , 安胜利

钢铁钒钛 doi:10.7513/j.issn.1004-7638.2016.03.021

转炉冶炼脱磷期间渣中含有一定量的固态CaO颗粒,为研究磷在CaO颗粒中的传递速度,在1385～1450℃,CaO饱和的CaO-SiO2-FetO-P2O5熔渣中用钼丝吊入CaO颗粒,分别保温10、20、30、60、100 s,之后取出空冷,采用SEM-EDS测量非均相脱磷渣中磷在CaO颗粒和渣间的分配并计算扩散系数,研究了温度对磷在CaO固相颗粒中的扩散速度的影响.结果表明,在试验温度下磷能够扩散进入CaO固体颗粒中,但由于CaO颗粒与渣中物质作用,磷的进一步扩散变得困难.1400℃下磷在CaO颗粒中的扩散速率常数DP为9.536× 10-10 m2/s;1385、1450℃时,DP分别为5.75749×10-10、7.42× 10-9m2/s.在1380～1450℃,CaO-SiO2-FetO-P2O5熔渣中磷在CaO颗粒中的扩散活化能为9.638× 105 J/mol.

关键词: 转炉 , 高磷铁水 , 脱磷 , CaO固相颗粒 , 扩散速率

Phase transition and elastic constants of CaO from first-principle calculations

Physica B-Condensed Matter

The structural B1-B2 phase transition of CaO and the elastic properties of the B1 phase of CaO are investigated by ab initio plane-wave pseudopotential density functional theory method. The dependences of the elastic constants c(ij), the aggregate elastic modulus B-s and G, the elastic anisotropic parameter A, and the Debye temperature Theta(D) on pressure are successfully discussed. From the usual condition of equal enthalpies, we find that the structural B1-B2 phase transition of CaO occurs at 62.8GPa, consistent with the experimental value 61 GPa. From our elastic constants of CaO under pressure, we find that the B1-B2 structural transformation occurs at about 178 GPa by the elastic instability, which is far higher than the transition pressure 62.8 GPa. (c) 2006 Elsevier B.V. All rights reserved.

关键词: phase transition;elastic properties;generalized gradient;approximation;CaO;alkaline-earth oxides;high-pressure;ab-initio;thermodynamic;properties;crystals;mgo;pseudopotentials;instabilities;temperature;stress

超细CaO粉炉内喷射脱硫的实验研究

钟北京 , 姚海军 , 何裕昆 , 周明德 , 傅维镳

工程热物理学报

本文对超细CaO粉炉内喷射脱硫进行了实验研究,分析了可能影响超细CaO粉炉内脱硫效率的多种因素,实验结果表明:使用预先煅烧生成的超细CaO粉在并不苛刻的反应条件下脱硫效果很好,颗粒大小、反应区温度、反应时间和Ca/S比对炉内喷钙脱硫的效率有重要的影响.

关键词: 脱硫 , 超细CaO , 实验研究

冷却方式对钢渣中f-CaO显微形貌及含量的影响

张玉柱 , 雷云波 , 李俊国 , 邢宏伟 , 韩志杰 , 龙跃

钢铁钒钛

采用扫描电子显微镜和化学分析方法对三种不同方式处理的钢渣中f-CaO的显微形貌及含量进行分析研究,试验结果表明,钢渣中弥散型f-CaO主要形成于C2S和C3S初晶、RO相形成和C3S分解等过程,其数量多、分布广、粒径较小；缓冷渣中氧化钙的典型显微形貌为灰色圆粒状、薄膜状、细小长条状；气淬渣中氧化钙的典型显微形貌为灰色薄膜状和细小长条状；热焖渣中氧化钙典型显微形貌为细小长条状；冷却强度对钢渣中f-CaO含量影响显著,因此冷却强度最弱的缓冷渣中f-CaO含量达到了6.96％,而冷却强度最高、经过水解的热焖渣中f-CaO含量只有0.55％；前期冷却强度高、后期冷却强度弱的气淬渣中f-CaO含量为2.28％；降低气淬钢渣粒径,可降低渣中f-CaO含量,从而提高其综合利用价值.

关键词: 钢渣 , 冷却强度 , 自由氧化钙 , 显微形貌 , 缓冷渣 , 气淬渣 , 热焖渣