材料期刊网

Shift From Coke to Coal Using Direct Reduction Method and Challenges

Okonkwo Paul Chukwuleke , CAI Jiuju , Sam Chukwujekwu , XIAO Song

钢铁研究学报(英文版)

Ironmaking involves the separation of iron ores. It not only represents the first step in steelmaking but also is the most capitalintensive and energyintensive process in the production of steel. The main route for producing iron for steelmaking is to use the blast furnace, which uses metallurgical coke as the reductant. Concerns over the limited resources, the high cost of coking coals, and the environmental impacts of coking and sinter plants have driven steelmakers to develop alternative ironmaking processes that can use noncoking coals to reduce iron ores directly. Since the efficiency and productivity of modern large capacity blast furnaces will be difficult to surpass, blast furnaces will continue to retain their predominant position as the foremost ironmaking process for some time to come. The alternative ironmaking processes are therefore expected to play an increasingly significant role in the iron and steel industry, especially in meeting the needs of smallsized local and regional markets. It is likely that the importance of direct reduced iron (DRI) and hot metal as sources of virgin iron will continue to increase, especially in the developing countries where steelmaking is, and will be, primarily based on electric arc furnace (EAF) minimills. Consequently, the challenges that are faced by the new technology have to be embraced.

关键词: ironbearing material;coke;flux;coal;blast furnace;sintering;iron ore

Study of Carbon-poor Regions of Austenite during Bainitic Incubation Period by SAM

Xiaolei WU , Husheng JIA , Xiyan ZHANG and Mokuang KANG(Dept. of Materials Science & Engineering , Northwestern Polytechnical University , Xi'an , 710072 , China)(To whom correspondence should be addressed)

材料科学技术（英文）

The variation of carbon composition in undercooled austenite during bainitic incubation period has been investigated in 40CrMnSiMoVA by scanning auger microprobe (SAM). The results show that the outstanding diffusion and redistribution of carbon occur in isothermally reacted specimens. This leads to the formation of carbon-poor regions (CPR) near austenite grain boundaries and in austenite grains. The carbon content in CPR exceeds the equilibrium carbon composition of ferrite. Furthermore, it is indicated that the existence of CPR is thermodynamically possible.

关键词:

SAM AND XPS STUDIES ON SURFACE SEGREGATION OF SUBSTRATE ELEMENTS IN Au-Ni-KOVAR ALLOY SYSTEM

QI Yunxin TANG Wentai XIA Jianguo Nei Mongol Institute of Metallic Materials , Baotou , ChinaLI Wang ZHAN Zhenzong Institute of Physical and Chemical Engineering Research , Tianjin , China

金属学报(英文版)

The surface segregation of substrate elements through the Au layer in the Au-Ni-Kovar sys- tem specimens heated at 250—350℃ for 0.5—1.5 h has been studied by SAM and XPS. Visual evidence of the mechanism for Ni and Co surface segregation of the complicated sys- tem has been given,i.e.Ni and Co penetrated the gold layer mainly by grain boundary diffu- sion and then covered the Au layer by surface diffusion.The strdy results of the chemical states of surface segregation elements not only indicate that oxygen adsorption and oxidation reaction are the driving force for the surface segregation of Ni and Co,but also show that the above segregation can result in water absorption on surfaces.

关键词: Au-Ni-Kovar alloy system , null , null , null , null

Au-Ni-Kovar合金系统基底元素表面偏聚的SAM和XPS研究

齐芸馨 , 唐文泰 , 夏建国 , 李望 , 展振宗

金属学报

本文采用SAM和XPS对实用Au-Ni-Kovar合金系统热处理样品(250—350℃,0.5—1.5h)进行了基底元素穿透Au层的表面偏聚研究,给出了这一复杂系统中Ni,Co表面偏聚机理的直观证据,即Ni,Co主要是通过晶界扩散穿透Au层而后以表面扩散覆盖镀Au表面的;表面偏聚元素化学态的研究则不仅表明,氧的吸附和氧化反应是Ni,Co表面偏聚的驱动力,而且发现,上述偏聚会引起样品表面吸水的现象。

关键词: Au-Ni-Kovar合金系统 , surface segregation , substrate element , SAM , XPS

基于SAM的不锈钢点焊接头无损检测

孙鑫宇 , 曾凯 , 何晓聪 , 张龙 , 胡伟

宇航材料工艺 doi:10.3969/j.issn.1007-2330.2015.06.017

运用超声波扫描显微镜(SAM)对1 mm厚SUS304不锈钢薄板点焊接头进行无损检测,分析不同焊接工艺条件下的C扫描图像,并对C扫描图像各特征区域的A扫描信号进行采集、分析,研究两者间的对应关系,通过超声波C扫描成像法对焊核直径进行测量.结果表明:超声波扫描显微镜可以检测不锈钢点焊接头缺陷,并通过C扫描图像区分缺陷类型;在电极压力为0.15 MPa、焊接电流大于8 kA时,C扫描图像可以清楚的反映飞溅、过烧等缺陷;C扫描图像各特征区域表现出不同的A扫描信号特征;基于超声波C扫描测量的焊核直径为4.39-5.25 mm.

关键词: SUS304不锈钢 , 点焊接头 , 超声波C扫描 , A扫描

SAM ANALYSIS OF NITRIDE IN 30CrNi STEEL

QI Yunxin Nei Monggol Institute of Metallic Materials , Baotou , China QI Yunxin , Professor , P.O.Box No.4 , Baotou 014034 , Nei Monggol , China

金属学报(英文版)

The nitride in 30CrNi steel and its composition along boundaries have been studied by means of scanning Auger microprobe.The nitride identified metallographically is Zr(C,N)which contains a small amount of Ti and O.The interface width between the Zr(C,N)and the matrix is about 1.6 μm.An Fe-rich shell is.found on the surface of Zr(C,N)which appeared on the fracture surface.The thickness of shell is 0.1-0.8μm.The Fe concentration of its outmost layer is 3-18 at.-% and decreases exponentially along the depth direction.

关键词: nitride , null , null , null , null

CNTs/RE-SAM的制备及其吸收光谱分析

雷子恒 , 王传英 , 程先华

表面技术

用混和酸对碳纳米管进行功能化处理,并配制稀土改性碳纳米管悬浮液,通过自组装技术在单晶硅表面制备稀土改性碳纳米管复合薄膜.XPS和SEM检测结果表明:功能化处理后,碳纳米管表面含有羟基、羧基等官能团；稀土改性溶液中稀土的质量分数为0.3％时,对碳纳米管的改性效果最明显.从吸收光谱可以看出,稀土改性碳纳米管复合薄膜在紫外-可见光区域均有吸收,特征峰相对密集在紫外光区域,能够拓展晶体硅太阳能电池的光谱响应范围.

关键词: 碳纳米管 , 稀土 , 功能化 , 吸收光谱

Factors affecting the quality and corrosion inhibition ability of self-assembled monolayers of a Schiff base

Corrosion

Self-assembled monolayers (SAM) of a Schiff base were prepared on a copper surface under different conditions, and the quality and protection ability of resulting films against aqueous corrosion of copper were evaluated by alternating current (AC) impedance technique. Some factors, including surface treatment and applied potentials during and after self-assembly, were investigated. The results indicate that nitric acid (HNO3) etching of the copper prior to adsorption can improve the quality and corrosion inhibition ability of SAM significantly. An appropriately applied potential during self-assembly contributed to the improvement of the quality of SAM, and the long hydrocarbon chain in the molecular structure of the Schiff base enhanced the protection of SAM. Fourier transform infrared (FTIR) reflection spectroscopy and x-ray photoelectron spectroscopy (XPS) were used in the analysis of SAM.

关键词: alternating current impedance;aqueous corrosion;copper;films;Fourier;transform infrared reflection spectroscopy;Schiff base;self-assembled;monolayers;x-ray photoelectron spectroscopy;electrochemical impedance spectroscopy;copper corrosion;protection;films;alkanethiols;coatings;nacl;eis

表面纳米结构及其自由能对滴状冷凝传热的影响

马学虎 , 汪明哲 , 兰忠 , 王四芳 , 李晓楠

工程热物理学报

通过抛光和氧化刻蚀方法在基体壁面形成微米和纳米尺度的微观结构,然后制备十八烷基硫醇分子自组装膜,从而得到空气中表观接触角为160°的SAM-1表面和空气中表观接触角为116°的SAM-2表面.实验研究了常压条件下两类表面的滴状冷凝传热特性.结果表明两种表面都能够有效提高冷凝传热效果.但是,具有表面纳米结构的SAM-1表面的滴状冷凝传热特性低于SAM-2表面.分析了纳米结构和液固自由能差效应对滴状冷凝传热影响的共同作用机理.

关键词: 滴状冷凝传热 , 表面自由能差 , 表面纳米结构 , 疏水表面

聚苯胺/凹凸棒纳米纤维的制备及性能研究

邵亮 , 冯洁 , 李强德

功能材料 doi:10.3969/j.issn.1001-9731.2013.20.030

使用硅烷偶联剂苯胺甲基三乙氧基硅烷(AMTES)改性凹凸棒粘土(ATP),制备了表面具有自组装单片层的SAM-ATP,并以其为模板,制备了结构较为均一的 SAM-ATP/PANI 纳米纤维。对制备工艺中 SAM-ATP 的用量进行了探讨,研究表明,当SAM-ATP含量为15.4%(质量分数)时,SAM-ATP/PANI纳米纤维结构较为均一、分散性良好,且具有最好的室温电导率2.3×10-4 S/cm,使用紫外-可见分光光度计(UV-Vis)对电导率的变化原因进行了分析,使用热重分析仪(TGA)对材料的热稳定性进行了探讨,研究显示SAM-ATP的引入可有效提高PANI热稳定性。使用傅立叶变换红外分光光度计(FT-IR)和透射电子显微镜(TEM)对 SAM-ATP/PANI 纳米复合材料的结构和形貌进行了表征。

关键词: 聚苯胺 , 凹凸棒 , 苯胺甲基三乙氧基硅烷 , 纳米纤维 , 热稳定性