A.A.El-Meligi
材料科学技术（英文）
Al-alloy (AA5022) corrosion penetration (CP) and crystal structure were investigated after running static immersion corrosion tests in 1 mol/L HCl solution and different concentrations of rare earth elements (La3+), (Ce3+) and their combination, at different temperatures. X-ray diffraction (XRD) was used to examine the surface structure before and after immersion, and secondary electron detector (SED) was operated to study surface morphology. In 1 mol/L HCl solution the corrosion penetration increased with increasing temperature and immersion time. The increase of La3+ concentrations up to 1000×10-6 g/L led to the decrease in the corrosion penetration, and the decrease in Ce3+ concentrations up to 50×10-6 g/L decreases the corrosion penetration of the alloy. Mix3 (combination of La3+ and Ce3+) dramatically reduced the corrosion penetration. This suggests that a synergistic effect exists between La3+ and Ce3+. The reaction kinetics both in absence and presence of La3+ and Ce3+ and their combination would follow a parabolic rate law. The XRD patterns revealed that the intensities of certain hkl phases are affected. The crystalline structure has not been deformed either before or after testing and there are no additional peaks except that of the as-received alloy. In the case of accelerating CP, the surface morphology shows that the roughness and voids of surface are increased.
关键词:
Al-alloy
,
Corrosion
,
penetration
,
Crystal
,
<span style="color:red">sspan>
王智宇
,
陈景鑫
,
张福安
,
钱国栋
,
樊先平
稀有金属材料与工程
通过水热法合成分散性良好的CdS纳米颗粒,并采用声化学法在颗粒外包覆TiO2壳层,获得的复合材料具有更好的光催化特性.讨论了水热反应温度保温时间与晶粒尺寸、结晶性之间的关系以及声化学制备过程中反应条件与陈化时间对壳层生长的影响.采用X射线衍射、透射电镜、漫反射光谱、光催化性能测试等手段表征CdS颗粒的尺寸、形貌及CdS/TiO2的结构与光催化特性.结果表明:水热过程中,提高反应温度、保温时间有利于提高产物的结晶性.声化学合成CdS/TiO2复合材料过程中,超声作用能促进核壳结构的形成.提高前驱溶液的浓度,在获得CdS/TiO2核壳结构的同时会析出TiO2纳米粒子.在降解甲基橙的实验中,CdS/TiO2材料表现出比单组分材料更好的催化性能.
关键词:
核壳结构
,
水热法
,
声化学法
,
光催化
沈江南
,
蒋婷婷
,
冯杰
高分子材料科学与工程
以S,S-二（α,α′-二甲基-α″-丙烯酸）三硫代碳酸酯（BDATC）为链转移剂,甲基丙烯酰胺（MAM）为第一单体,通过可逆加成断裂链转移聚合（RAFT）法合成出链转移剂（PMAM-CTA）,以N-乙烯基吡咯烷酮（NVP）作为第二单体合成PAM-b-PNVP,再水解得到含有氨基和羧基的CO2分离固定载体膜材料N-乙烯基-γ-氨基丁酸钠-丙烯酸钠共聚物（VSA-SA）。通过FT-IR、1H-NMR、XRD和DSC对PMAM-CTA、PMAM-b-PNVP和VSA-SA进行表征,采用GPC测定分子量及分子量分布。研究发现,该聚合具有活性可控聚合的特征,聚合动力学呈一级线性关系,得到数均相对分子质量可控、相对分子质量分布（1.2～1.3）窄的聚合物。与自由基聚合产物相比,水解产物VSA-SA的结晶度减小,载体含量增加。
关键词:
可逆加成断裂链转移聚合
,
嵌段共聚物
,
固定载体
,
<span style="color:red">Sspan>,<span style="color:red">Sspan>-二(α,α′-二甲基-α″-丙烯酸)三硫代碳酸酯
