氧化时间对2A12铝合金阳极氧化膜开裂行为的影响

采用不同阳极氧化时间制备氧化膜,并采用扫描电镜、电子探针、连续性检测、交流阻抗法和盐雾腐蚀试验对阳极氧化膜进行了研究。结果表明,不同阳极氧化时间生成的氧化膜层经热冲击后都会出现非穿透性裂纹;随阳极氧化时间延长,经热冲击后,氧化膜层裂纹密度增大。综合考虑不同氧化时间下制备的氧化膜的开裂行为和耐蚀性变化,阳极氧化30 min制备的膜层在热冲击后具相对较好的防护性能。     

二次阳极氧化对6061铝合金氧化膜结构和耐蚀性的影响

目的 研究相同工艺参数下一次阳极氧化和二次阳极氧化对6061铝合金上氧化膜结构的影响,探究基体结构差异性与膜层生长行为及性能间的对应关系。方法 以商业6061铝合金和SPS粉末烧结铝合金为研究对象,针对不同基体在一次阳极氧化和二次阳极氧化过程中,围绕基体组织特征对膜层结构的影响展开系统研究。同时,对不同工艺方法制备出的不同结构特点的氧化膜进行封闭后处理,结合电化学测试方法对膜层的耐蚀性能进行分析对比。结果 相比一次氧化过程,商业6061铝合金和SPS铝合金的二次氧化电流密度分别由12.07、56.62 mA/cm2增加至13.68、64.8 mA/cm2,膜层生长速率增大。同时,一次氧化后在基体表面形成的有序凹坑结构有助于二次氧化中膜层多孔结构有序性的提升,其中SPS烧结铝合金膜层孔洞呈规则的“六边形”结构。二次阳极氧化过程可以有效减少基体表面阴极性金属间化合物颗粒的分布,提高氧化膜的连续性,增强相应膜层的耐蚀性。结论 二次阳极氧化可以使生成的氧化膜层更加均匀规整,且整体耐蚀性显著提高。     

Microstructure and abrasive wear behaviour of anodizing composite films containing Si C nanoparticles on Ti6Al4V alloy

Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS） and X-ray photoelectron spectroscopy（XPS） were employed to characterize the morphology and composition of the films fabricated in the electrolytes with and without addition of Si C nanoparticles. Results show that Si C particles can be successfully incorporated into the oxide film during the anodizing process and preferentially concentrate within internal cavities and micro-cracks. The ball-on-disk sliding tests indicate that Si C-containing oxide films register much lower wear rate than the oxide films without Si C under dry sliding condition. Si C particles are likely to melt and then are oxidized by frictional heat during sliding tests. Potentiodynamic polarization behavior reveals that the anodized alloy with Si C nanoparticles results in a reduction in passive current density to about 1.54×10-8 A/cm2, which is more than two times lower than that of the Ti O2 film（3.73×10-8 A/cm2）. The synthesized composite film has good anti-wear and anti-corrosion properties and the growth mechanism of nanocomposite film is also discussed.     

Preparation of ZAO film by low-temperature hydrothermal approach and its electrical property

Al-doped ZnO (ZAO) films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3+ to Zn2+ was 1∶100, the annealing temperature and time were 200 ℃ and 2-6 h, respectively. The structure of the thin films was identified by X-ray diffraction (XRD), the surface morphology and thickness of the thin films were observed by scanning electron microscopy (SEM), and the electrical performance of the thin films was measured by four-point probes. It was shown that the films with an average particle size of 27.53 nm had a preferential orientation along (002), Al3+ had replaced the position of Zn2+ in the lattice without forming the Al2O3 phase and its thickness was 20-25 μm. With the increased annealing time, the intensity of diffraction peaks was decreased, the film exhibited irregular surface morphology gradually, and the resistivity of ZAO films was increased. The lowest resistivity obtained in this study was 3.45×10-5Ω·cm.     

TPN-十二烷基磺酸钠-层状双金属氢氧化物纳米杂化物的制备及防霉性能研究

实验制备了MgAl-TPN-十二烷基磺酸钠-层状双金属氢氧化物(MgAl-TPN-SDS-LDHs, 以下简称TPN-SDS-LDHs)纳米杂化物, 在醇酸树脂涂层中实现了缓慢且持续释放, 提高了TPN的防霉持久性。采用十二烷基磺酸钠(SDS)将非离子型、难溶性有机防霉剂2,4,5,6-四氯-1,3-苯二甲腈(TPN)包裹成阴离子表面活性剂胶束, 然后利用共沉淀法插层到MgAl-LDHs主体层间。利用X射线衍射、傅里叶红外光谱、扫描电子显微镜、透射电子显微镜和紫外?可见吸收光谱进行表征。结果表明: TPN插层成功, 在杂化物中的载药量为34.49%, 杂化物呈典型层状形貌。在乙酸丁酯中该纳米杂化物缓慢释放, 符合准二级动力学方程。将TPN-SDS-LDHs纳米杂化物应用于醇酸树脂涂层中并进行霉菌试验, 结果表明添加TPN-SDS-LDHs纳米杂化物涂层的防霉持久性能优于添加TPN涂层。     

BIT-层状双金属氢氧化物纳米杂化物的制备及防霉性能研究

采用共沉淀法将防霉剂1, 2-苯丙异噻唑啉-3-酮(BIT)成功插入到Mg-Al层状双金属氢氧化物层间(LDH), 合成Mg₂Al-BIT LDHs纳米杂化物。采用X射线衍射、傅里叶红外光谱、扫描电子显微镜进行表征。并在pH=4.8和7.2的介质中研究药物缓释动力学。结果显示BIT成功地插入到了LDH的层间, 载药量为44.35%, 释放动力学过程符合准二级动力学方程。将胶囊型防霉剂添加到醇酸树脂涂层中进行霉菌试验。结果表明Mg₂Al-BIT LDHs在耐耗、溶出、析出方面优于BIT, 后期防霉效果更好。     

石墨烯-银纳米粒子复合材料的制备及表征

以无毒、绿色的葡萄糖为还原剂, 在没有稳定剂、温和的液相反应条件下, 同时还原氧化石墨和银氨溶液中的银氨离子, 原位制备石墨烯-银纳米粒子复合材料. 采用X射线衍射、红外吸收光谱、拉曼光谱、扫描电镜和透射电子显微镜对所制备的石墨烯-银纳米粒子复合材料进行了表征. 结果表明: 氧化石墨和银离子在反应过程中同时被葡萄糖还原, 银纳米粒子均匀分布于石墨烯片层之间, 生成的银纳米粒子中大多数存在着孪晶界, 银纳米粒子的大小和分布受硝酸银用量的影响, 在合适的银离子浓度下, 负载在石墨烯片层上的银纳米粒子的粒径分布集中在25 nm左右; 复合材料中石墨烯的拉曼信号由于银粒子的存在增强了7倍.     

Ni0.5Zn0.5Fe2O4粉末化学镀铜前后的电磁性能

本文用溶胶-凝胶自燃烧法制备了Ni0.5Zn0.5Fe2O4粉末颗粒,以甲醛为还原剂在Ni0.5Zn05Fe2O4颗粒表面进行了化学镀铜,制备了Cu/Ni0.5Zn0.5Fe2O4复合粉体.用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对镀铜前的Ni0.5Zn0.5Fe2O4颗粒以及镀铜后的复合纳米颗粒进行了表征.对镀铜前的Ni0.5Zn0.5Fe2O4粉体和不同镀铜量的Cu/Ni0.5Zn0.5Fe2O4复合粉体进行了电磁性能的研究,结果表明镀铜后镍锌铁氧体的吸波性能明显提高,增重量为65%的Cu/Ni0.5Zn0.5Fe2O4复合粉体在频率为11GHz处反射率可达-12dB左右.     

基于灰色理论的高强铝合金应力腐蚀开裂预测模型的建立与应用

采用3.5%NaC1溶液中预制裂纹的方法测试了2124高强铝合金的应力腐蚀裂纹扩展长度随时间的变化,获得了裂纹扩展速率随腐蚀时间的变换规律及应力腐蚀断裂韧性界限值,并对断口进行分析.根据裂纹扩展的基本规律,运用灰色理论GM(1,1)模型,依据2124铝合金应力腐蚀开裂裂纹扩展长度的原始数据进行了灰色预测,并对预测结果进...     

三种有机物对LY12CZ铝合金在酸性溶液中的缓蚀行为研究

本工作选取了2-巯基苯并噻唑(MBIH)、苯并三氮唑(BTA)和8-羟基喹啉(8Q)等几种典型的缓蚀剂,研究了其对LY12CZ铝合金在酸性溶液中的缓蚀效果及机理.通过腐蚀失重法研究了三种缓蚀剂对LY12CZ铝合金在酸性溶液中腐蚀动力学的影响.利用光学显微镜(OM)、场发射扫描电子显微镜(FE-SEM)及能谱(EDS)等...