材料期刊网

Sulphidation of Fe-Nb,Co-Nb and Ni-Nb Alloys in H_2-H_2S at 700℃

F.Gesmundo F.Viani Instituto di Chimica , Facolta di Ingegneria , Universita di Genova , Genova , 16129 , ItalyY.NIU Corrosion Science Lab. , Institute of Corrosion and Protection of Metals , Academia Sinica , Shenyang , 110015 , China

材料科学技术（英文）

The corrosion of alloys based on Fe,Co and Ni containing 15 and 30 wt-% Nb was studied at 700℃ in H_2-H_2S mixtures providing 10~(-8) atm S_2.The Fe and Co-based alloys formed duplex scales with an outer layer of pure base-metal sulphide and an inner layer containing both metals.The Nb addi- tions were not able to produce exclusive Nb sulphidation but yielded a significant decrease of the corrosion rates for both types of alloys with respect to the pure metals even though they were still much higher than that of pure Nb.The Ni-base alloys corroded rapidly forming a single complex scale layer,mainly due to the appearance of a liquid Ni-S solution.

关键词: niobium , null , null , null

CLAS+FROST: new generation of photoproduction experiments at Jefferson Lab.

中国物理C

关键词:

CORRELATION BETWEEN STRESS COMPONENTS AND STRESS CORROSION CRACKS IN BRASS Lecturer,Department of Materials Physics,University of Science and Technology Beijing,Beijing 100083,China

QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing , Beijing , China

金属学报(英文版)

The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.

关键词: stress corrosion cracking , null , null , null

LaB6功能陶瓷材料的研究现状

郑树起 , 闵光辉 , 于化顺 , 韩建德 , 王维倜 , 张树玉

材料导报

综述了目前国内外LaB6功能陶瓷材料的研究概况及应用,综合了制备LaB6粉末、多晶、单晶的各种工艺.

关键词: LaB6 , 功能陶瓷 , 制备工艺

Corrosion Science Laboratory,Academia Sinica(CSL AS)

材料科学技术（英文）

关键词:

Stereology in Materials Science

LIU Guoquan Department of Materials Science and Engineering , University of Science and Technology Beijing , 100083 , China.

材料科学技术（英文）

Quantitative analysis of populations having a geometric structure,which has developed into a special scientific subject called microstructology or stereology,is of great importance to the characterization and evaluation of microstructures and their evolution in various processes.This paper, besides a brief discussion on those topics such as the recent developments of computer assisted image analysis,mathematical morphology,and fractal analysis,will mainly focus on the scope,fundamen- tals,present status,and perspectives of classical stereology.Several case examples of its application to materials science will also be given.

关键词: stereology , null , null , null

Effect of CO2 on atmospheric corrosion of UNS G10190 steel under thin electrolyte film

Chemical Research in Chinese Universities

The atmospheric corrosion of UNS G10190 steel under a thin electrolyte film in the atmosphere polluted by CO2 has been studied in the lab using an atmospheric corrosion monitor (ACM) in combination with XRD and SEM observations of the surface of steel. The ACM study indicated that the corrosion rate of the steel increased with increasing carbon dioxide concentration. The XRD and SEM observations showed that no carbonate was found in the corrosion product on the steel surface. The corrosion product consisted of two layers, i.e., inner and outer layer. From the experimental results, it was concluded that CO2 played an enhancing role in the atmospheric corrosion of UNS G10190 steel. The film of the corrosion product showed slight protection.

关键词: atmospheric corrosion;thin electrolyte film;carbon dioxide;ACM;UNS;G10190 steel;zinc

La2O3-B4C系反应合成LaB6粉末

郑树起 , 闵光辉 , 邹增大 , 王效志 , 韩建德

金属学报

系统研究了利用La2O3和B4C粉制备LaB6粉末的反应合成工艺.La2O3-B4C系反应热力学分析表明反应产物的气体分压对LaB6的形成有重要影响,减小气体分压可以明显降低LaB6的合成温度,结合DTA测定结果,确定了LaB6粉末的合成温度.利用X射线衍射分析了不同温度和保温时间条件下所生成粉末的相组成,并分别用扫描电镜和化学分析方法分析了所生成LaB6粉末的颗粒尺寸、形貌及纯度.实验结果表明,La2O3-B4C系制备LaB6粉末的优化工艺是真空度133 Pa,1673 K保温2.5 h,所合成的LaB6粉末颗粒比较规整,大多呈近似圆球形,平均直径3μm,纯度达98.2%.

关键词: La2O3 , null , null , null , null

La2O3-B4C系反应合成LaB6粉末

郑树起 , 闵光辉 , 邹增大 , 王效志 , 韩建德

金属学报 doi:10.3321/j.issn:0412-1961.2001.04.018

系统研究了利用La2O3和B4C粉制备LaB6粉末的反应合成工艺.La2O3-B4C系反应热力学分析表明反应产物的气体分压对LaB6的形成有重要影响,减小气体分压可以明显降低LaB6的合成温度,结合DTA测定结果,确定了LaB6粉末的合成温度.利用X射线衍射分析了不同温度和保温时间条件下所生成粉末的相组成,并分别用扫描电镜和化学分析方法分析了所生成LaB6粉末的颗粒尺寸、形貌及纯度.实验结果表明,La2O3-B4C系制备LaB6粉末的优化工艺是真空度133 Pa,1673 K保温2.5 h,所合成的LaB6粉末颗粒比较规整,大多呈近似圆球形,平均直径3μm,纯度达98.2%.

关键词: La2O3 , B4C , 反应 , 合成 , LaB6

常压固相反应合成 LaB₆ 粉末及其反应机理

徐秀华 , 肖汉宁 , 郭文明 , 高朋召 , 彭苏华

无机材料学报 doi:10.3724/SP.J.1077.2011.00417

以La₂O₃和B₄C为原料, 在常压下合成了LaB₆粉末. 计算了常压合成LaB₆的热力学条件, 采用XRD、 SEM、激光粒度分析表征了不同温度和保温时间合成的LaB₆粉末的物相组成、颗粒形貌和粒度分布, 探讨了LaB₆粉末的合成反应机理. 结果表明, 常压下1650℃保温2h的产物经酸洗后, 能得到纯度为99.22%具有立方体结构的LaB₆粉末. 当La₂O₃颗粒尺寸远小于B₄C时, 合成过程中LaB₆首先在B₄C表面生成, 随温度升高和保温时间延长, 未反应的La₂O₃和LaBO₃通过LaB₆壳不断扩散到B₄C核表面直至反应完全. 合成LaB₆粉末的初始形貌和尺寸主要取决于反应物B₄C原料 .

关键词: LaB₆ , thermodynamic , solid-state reaction , reaction mechanism