材料期刊网

TENSILE TESTING OF C/C COMPOSITES ATHIGH TEMPERATURES

Author S.R. Zhou , S.R. Qiao , S.H. Bai and C.S. Tian Faculty 401 , Northwestern Polytechnical University , Xian 710072 , ChinaManuscript received 18 October 1998

金属学报(英文版)

The tensile properties of three different carbonfiberreinforced carbon composites (C/C), mat C/C, 2D laminate and 4D C/C, were investigated under the combined influence of temperature and loading rate. From the experiments the following could be concluded: loading rate between 10-1-10 mm/min was valid; the fracture stress of the three kinds of C/C composites increased with increasing temperature in the range from room temperature to 1900, and the initial modulus of 2D laminate C/C composites increased with the increase of temperature up to 2000.

关键词: tensile testing , null , null , null

C-S-H 凝胶及其研究方法

杨南如

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2003.02.011

在分析C-S-H凝胶的复杂性和特征的基础上,就测定它的化学组成、C-S-H凝胶中[SiO4]4-四面体的聚合度及其结构的化学和物理的方法作了简要介绍.现代各种测试方法的出现和使用,对C-S-H凝胶的组成和集中[SiO4]4-四面体的聚合结构有了较为完整的概念.

关键词: C-S-H凝胶 , 化学组成 , 凝胶结构 , 测定方法

C-S-H凝胶对Pb(Ⅱ)的吸附固化作用

王昕 , 刘晶 , 汪澜 , 考宏涛

硅酸盐通报

以分析纯Ca(NO3)2·4H2O、Na2SiO3·9H2O、Pb(NO3)2为原料,通过溶液反应法,制备纯净的C-S-H凝胶和掺杂Pb的C-S-H凝胶,研究了C-S-H凝胶在形成过程中对Pb的吸附固化作用及掺杂Pb后C-S-H凝胶的结构变化.结果表明,可溶铅盐由2％增至6％时,C-S-H凝胶对Pb均有良好的吸附固化作用,俘获Pb总量增大.XRD图谱发现掺杂Pb的C-S-H凝胶,其主峰位置发生偏移,出现明显的Ca(OH)2衍射峰.红外测试表明含Pb C-S-H凝胶硅氧四面体的链接方式发生变化,Q2伸缩振动峰向低波数方向偏移,Q1伸缩振动峰吸收强度增加.

关键词: C-S-H凝胶 , Pb(Ⅱ) , 吸附固化

纳米无定形C-S-H凝胶颗粒及其结构表征

崔素萍 , 郭红霞 , 王辰 , 王子明

硅酸盐通报

以无水氯化钙( CaCl2)和水玻璃为原料,通过室温沉淀反应制备了水化硅酸钙(C-S-H)凝胶颗粒.采用SEM、FTIR、XRD、XRF、TEM等对不同C/S和pH值条件下制备的C-S-H凝胶颗粒的形貌和结构进行了表征.结果表明,较低pH值条件下制备的C-S-H凝胶颗粒间呈现不同程度的团聚,-Si-O键之间显示一定的聚合度,其平均粒径在15 ～25nm之间,且呈无定形结构；在pH值较高时,该凝胶颗粒呈半结晶结构.

关键词: 水化硅酸钙(C-S-H) , 凝胶颗粒 , 钙硅比(C/S)

Corrosion behaviour of carbon steel in different concentrations of HCl solutions containing H(2)S at 90 degrees C

Corrosion Science

The corrosion behavior of SAE-1020 carbon steel in H(2)S-containing solutions with different concentration of HCl at 90 degrees C was investigated by weight loss, electrochemical measurements, SEM and XRD analysis. The results showed that the corrosion rate of carbon steel increased with increasing HCl concentration. Uniform corrosion was found on the carbon steel surface in H(2)S + HCl solutions, while corrosion cavities were observed in the solution only containing H(2)S. The ratio of Faradaic process of total corrosion process increased with the increase of HCl concentration. The corrosion products were solely composed of mackinawite in the H(2)S-containing solutions with or without HCl. (c) 2011 Elsevier Ltd. All rights reserved.

关键词: Steel;Weight loss;EIS;SEM;XRD;Acid corrosion;acidic chloride solutions;hydrogen-sulfide;aqueous-solution;iron;sulfides;electrochemical-behavior;media;dissolution;impedance;polarization;environments

The effect of H(2)S concentration on the corrosion behavior of carbon steel at 90 degrees C

Corrosion Science

The electrochemical behavior of SAE-1020 carbon steel in 0.25 M Na(2)SO(4) solution containing different concentrations of H(2)S at 90 degrees C was investigated using the methods of weight loss, electrochemical measurements, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the corrosion rate of carbon steel increased significantly with the increase of H(2)S concentration. H(2)S accelerated the corrosion rate of SAE-1020 carbon steel by a promoted hydrogen evolution reaction. Severe corrosion cavities were observed on the carbon steel surface in the solutions containing H(2)S due to cementites stripped off from the grain boundary. The loose corrosion products formed on the steel surfaces were composed of mackinawite. (C) 2010 Elsevier Ltd. All rights reserved.

关键词: Steel;Weight loss;SEM;XRD;Acid corrosion;hydrogen-sulfide;acid-solutions;electrochemical-behavior;aqueous-solution;iron sulfides;chloride solutions;impedance;media;environments;dissolution

固体核磁共振技术在C-S-H中的研究进展

孙倩 , 管学茂 , 勾密峰 , 朱建平

硅酸盐通报

C-S-H是水泥水化的主要胶凝材料,其结构直接影响混凝土工程性,由于其结晶度较低,中短程有序,采用固体核磁(NMR)可作为分析其结构的方法之一.本文从C-S-H的模型,NMR中特征参数,平均分子链长(MCL)和聚合度三个角度,对水化龄期、掺合料、钙硅比三个方面进行了综述,并展望了固体核磁技术在C-S-H中的发展趋势.

关键词: C-S-H , 聚合度 , MCL , 核磁共振

The sulfidation of a Cu-15 vol.% Nb alloy in H-2-H2S mixtures at 400-600 degrees C

Oxidation of Metals

The corrosion of a Cu-15 vol.% Nb alloy by H-2-H2S mixtures has been studied under 10(-12) atm S-2 at 400 and 500 degrees C and under 10(-10) atm S-2 at 500 and 600 degrees C. The alloy is a two-phase mixture of the two terminal solid solutions and is composed of a Cu-rich matrix containing particles of the Nb-rich phase elongated parallel to the sample surface and isolated mainly from each other. The alloy corroded at rates similar to those of pure copper at 400 and 500 degrees C under 10(-12) atm S-2, but more slowly than pure copper at 500 and 600 degrees C under 10(-10) atm S-2. The scales were duplex, containing an external layer of pure copper sulfide and an inner very porous region composed of a mixture of sulfides of the two metals in which, however, the core of the large Nb particles was still uncorroded.

关键词: niobium;copper;sulfidation;2-phase binary-alloys;high-temperature oxidation;low-oxygen pressures;most-reactive component;possible scaling modes;low oxidant pressures;1 atm o-2;h2-h2s mixtures;600-800-degrees-c;corrosion

Corrosion of Y, Fe and Fe-15Y in H-2-H2S mixture under 10(-3) Pa S-2 at 600 similar to 800 degrees C

材料科学技术（英文）

The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.

关键词: high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation

配合物[Sm(C7H5O3)2(C4H6NO2S)]·2H2O的热化学研究

杨德俊 , 李旭 , 李强国 , 肖圣雄 , 张应军 , 黄熠

中国稀土学报

将六水氯化钐,水杨酸与硫代脯氨酸3种物质一起反应,制得了一种新的稀土三元固体配合物[Sm(C7H5O3)2(C4H6NO2S)]·2H2O(s).通过红外光谱、热重差热分析、元素分析等手段确定了其结构与组成.在常压、298.15 K下,分别测定了六水氯化钐、水杨酸、硫代脯氨酸和该配合物在混合溶剂(二甲亚砜:乙醇:3 mol·L-1HCI=1:1:1)中的溶解焓,并根据热化学原理得出了298.15 K时配合物[Sm(C7H5O3)2(C4H6NO2S)]·2H2O(s)的标准摩尔生成焓△fHθm=(-2913.73±3.10)kJ·moL-1.

关键词: 稀土配合物 , 六水氯化钐 , 硫代脯氨酸 , 水杨酸 , 热化学