Ni－3．5Al合金在575℃氯气环境中的腐蚀

Ｎｉ－３．５Ａｌ合金在５７５℃氯气环境中的腐蚀涂江平，毛志远，李志章（浙江大学）由于大多数金属材料均能与高温氯气反应生成低熔点、高蒸气压的金属氯化物［１］，从而表现出很高的腐蚀速度．镍基合金在６００℃以下干氯气环境中具有较好的腐蚀抗力，可以作为在高温...     

高温煤粉对氧——乙炔焰Ni-WC粉末喷涂层的冲蚀磨损

本文利用X射线衍射、能谱分析和扫描电镜研究了镍基碳化钨合金粉末氧——乙炔焰喷涂涂层。涂层中碳化钨的含量对涂层的组织结构和冲蚀磨损性能产生重要的影响。结果表明，碳化钨呈均匀弥散分布的Ni-WC35涂层在高温煤粉的作用下具有最佳的耐冲蚀性能。     

纳米晶Mg2-xTixNi0.8Cr0.2四元合金的气态储氢性能

纳米晶Mg2-xTixNi0.8Cr0.2(x=0.05,0.10,0.15,0.20)四元合金由纯Mg,Ti,Ni,Cr粉在773 K经4h烧结后机械球磨而成.该合金具有良好的活化性能和吸氢动力学性能.合金在393 K,4.0 MPa氢压条件下,2min内便可以完成总吸氢量的75%(质量分数)以上,Mg1.95Ti0.05Ni0.8C0.2最大吸氢量可达到3.35%.在493 K,0.1 MPa条件下可快速放氢,Mg1.80Ti0.20Ni0.8Cr0.2在18 min内便可完成放氢过程,总放氢量为2.17%.所有合金具有良好的低温吸氢性能,353 K时Mg1.85Ti0.15Ni0.8Cr0.2合金最大吸氢量可达到2.08%.XRD分析结果显示,Ti替代Mg后,合金中主要存在Mg2Ni与Ni两相,另外,还有微量的Mg与TiNi相,TiNi相弥散分布在合金中,对合金的吸放氢性能有一定的催化作用.     

CoO AS ADDITIVE IN POSITIVE ELECTRODE OF NICKEL-METAL HYDRIDE BATTERY

A series of positive electrodes for Ni/MH battery were fabricated by addition of CoO.The morphology and microstructure of the electrodes were examined by SEM and EDS, and electrochemical behavior was investigated in three-compartment appliances at room temperature.The electrochemical performance of the positive electrodes with CoO was improved. Under the same charge-discharge cycle, the electrodes with CoO showed higher specific capacity, lower charge mean voltage and higher discharge mean voltage. But further increasing the content of CoO in the electrodes contributed negative effect on the overall performance. Addition of 8% (mass) CoO was suggested to be a suitable content for the positive electrode.     

纳米石墨对铝基复合材料阻尼性能的影响

石墨因具有较高的阻尼性能,成为提高铝基复合材料阻尼性能的理想增强体。本文用爆轰合成的纳米石墨粉作为增强体,采用粉末冶金的方法,对纳米石墨(n-G r)-A l-Mg-S i复合材料进行了热压。X射线衍射表明烧结体中出现了Mg2S i强化相,场发射扫描电镜分析表明加入1%(质量分数)纳米石墨可以较好地分散在铝基材料中。通过对其阻尼性能进行研究,表明纳米石墨可以使复合材料的阻尼性能提高10%以上。     

Effect of surface treatment on the structure and high-rate dischargeability properties of ABs-type hydrogen storage alloy

Surface-treated MmNi_3.55Co_0.75Mn_0.4Al_0.3 alloy as negative electrode material of nickel-metal hydride battery was employed to improve the high-rate dischargeability. Surface treatment was realized by dipping and stirring the alloy into a HCl aqueous solution with various concentrations at room temperature. The microstructure of the alloy before and after surface treatment was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties before and after surface treatment were comparedand the alloy treated in 0.025 mol/L HCl solution showed the optimal high-rate dischargeability.     

纳米碳管增强铜基复合材料的力学性能和物理性能

制备了纳米碳管增强铜基复合材料,研究了材料的一些重要力学和物理性能.结果表明:复合材料中纳米碳管的分布较均匀,其最佳体积分数为12%～15%.材料的断裂以纳米碳管的拔出和桥接为主,磨损主要是氧化磨损.热膨胀系数αc约为9.36×10-6/℃,存在加热-冷却膨胀曲线滞后现象.材料的电阻率约为2.7×10-6Ω·cm,孔隙率是电阻率的重要影响因素.     

纳米石墨润滑油制备及其流变性研究

采用相转移工艺 ,以水性石墨滤饼、15 0SN基础油为原料制备了纳米石墨润滑油 ,并用ThermoHaake流变仪考察了其流变性质。结果表明 :纳米石墨润滑油液固分散体系具有剪切变稀的流变学行为 ;超分散剂的加入能阻止石墨粒子紧密团聚结构的形成 ,改善分散体系的稳定性。通过Casson方程拟合 ,可得到静态屈服应力值 ,由该值表征的体系稳定性表明 ,随高分子型分散剂加入量的增多 ,体系的稳定性也逐渐增强 ,直至达到一个恒定值。     

Photoelectrochemical characteristics of AB5-type hydrogen storage alloy modified with SrTiO3 photocatalyst

Perovskite-type SrTiO3 powders were prepared by using strontium acetate, tetrabutyl titanate and sodium hydroxide via direct hydrolysis-precipitatlon process. AB5-type hydrogen storage alloy（HSA） electrodes modified with SrTiO3 powders were prepared and the photoelectrochemical characteristics of the as-prepared electrodes were investigated. The results of cyclic voltammograph show that the current of reduction peak increases remarkably under the light irradiation. The obvious photochargeable properties are obtained for the hydrogen storage alloys modified with Perovskite-type SrTiO3 powders. During photocharging process, the potential of the electrode shifts quickly to negative direction and a potential plateau occurs. HSA electrode modified with SrTiO3 powders prepared by direct hydrolysis-precipitation process gives the higher potential of about -0.90 V（vs Hg/HgO） under the light irradiation. SEM observation discloses that a large amount of microcracks occur on the surface of the electrode after photocharging process, which is caused by the formation of hydride in the bulk of electrode.