锰结合预先热处理对铝硅合金中富铁相组织和力学性能的影响

探索了通过加入金属Mn并结合熔体热处理工艺来控制铝硅合金中富铁相的形态.结果表明:熔体经过预先热处理后,加入Mn可以使绝大多数针状铁相转变成块状铁相,且粒径均一;预先热处理可以减少Mn的加入量而取得较好的效果,适宜的加入量为x(Mn)/x(Fe)=0.5～1.1(摩尔比),并可以通过控制Mn的加入量来控制块状富铁相杂质的粒径大小;经过联合处理的含铁铝硅合金的抗拉强度提高40～80 MPa,伸长率提高6%～7%.     

Sound absorption and insulation property of closed-cell aluminum foam

The closed-cell aluminum foams （specimen p=0.31 g/cm^3, diameter of 100 nun, and thickness of 20 mm for sound absorption testing; specimen p=0.51 g/cm^3, length of 1 240 mm, width of 1 100 mm, and thickness of 30 mm for sound insulation testing） were prepared by the method of molten body transitional foaming process. Its sound absorption property under frequency of 160-2 000Hz and the sound insulation property under frequency of 100-4 000 Hz were tested. The sound absorption results show that the sound absorption property is much better under middle frequencies than that under low and high frequencies. The sound absorption coefficient climbs when frequency increases from 160 Hz to 800 Hz and then drops when frequency is increased from 800 Hz to 2 000 Hz. The function of the sound absorption mainly depends on the Helmholtz resonator, the microphone as well as cracks of closed-cell aluminum foam. The sound insulation experiments show that the sound reduction index （R） is small under low frequencies, and large under high frequencies; the weighted sound reduction index （Rw） and the highest sound reduction index （R） can reach around 30.8 dB and 43 dB, respectively.     

高容量A2B7型超晶格贮氢合金的发展历程及问题

综述了高容量稀土镁镍基A2B7型超晶格贮氢合金的发展历程,其大致可以分为1997～2004年、2005～2007年和2008年至今的3个阶段。目前,A2B7型合金可实现最大放电容量高于380mAh/g、循环寿命超过500周期,国内已进入产业化试制阶段。对于A2B7型合金,PuNi3、Ce2Ni7、Pr5Co19型等超晶格结构相的定量识别、产业化关键技术突破及其在高容量密封二次电池中的集成应用是未来几年需要重视并解决的问题。     

Effect of TiH2 on preparation of closed-cell aluminum foam and its compressive behavior

The vesicant problem during the process of preparing closed-cell aluminum foam by molten body transitional foaming process was discussed and the effect of granularity and addition of TiH2 on porosity of closed-cell aluminum foam was investigated. The static compressive behavior of closed-cell aluminum foam and the influence of porosity on static compressive property of closed-cell aluminum foam were researched as well. The results show that with increasing granularity of TiH2, the porosity of closed-cell aluminum foam firstly increases and then decreases gradually, the granularity should be controlled in the range of 38-74μm which can result in higher porosity. The porosity of closed-cell aluminum foam increases with the increasing addition of TiH2, and the addition of TiH2 should be controlled fi＇om 1.5% to 2.5% which can result in homogeneous cell and moderate strength of closed-cell aluminum foam. The compressive process of closed-cell aluminum foam obviously displays linear elastic phase, plastic collapse phase, and densification phase, and the compressive strength grows with decreasing porosity.     

Ni-Mo-Co合金电极制备工艺的研究

采用电沉积方法制备出Ni-Mo-Co三元合金电极,研究了沉积电流密度、镀液温度及镀液pH值等条件对合金电极析氢催化活性的影响.采用EDS和XRD分析合金电极的化学组成和晶态结构.通过对极化曲线的比较分析得出最佳制备工艺条件为:电流密度15 mA/cm2,镀液温度25℃和pH值为10.该条件下制备的Ni-Mo-Co合金电极为非晶态结构,外观呈银白色,表面光滑致密,其化学组成为34.09%Ni、59.51%Mo、6.40%Co.在30%KOH 溶液中,其析氢过电位为η100=112mV,比Ni电极降低了352 mV,表现出良好的析氢催化活性.     

La-Mg-Ni系A5B19相储氢合金热处理工艺研究

重点研究了热处理工艺对(LaNdPrMg) (NiCoAl)3.8合金相成分和电化学性能的影响.总结发现1323 K保温5h急冷的热处理过程,在改善相成分方面,可以使合金中高容量的A5B19相丰度达到68％(质量分数),电化学性能测试表明,其最大放电容量达到400.9 mAh·g-1,电化学循环100周容量保持率达到82.44％.经分析认为,加热保温过程对改善储氢合金相结构的均匀性起到一定的作用,而急冷过程对改善储氢合金综合性能起到至关重要的作用.     

Nd元素部分取代对La_(0.8-x)Nd_xMg_(0.2)Ni_(3.3)Co_(0.5)(x=0～0.15)储氢合金结构和电化学性能影响

研究了Nd元素部分取代对La0.8-xNdxMg0.2Ni3.3Co0.5(x=0～0.15)合金的相结构和电化学性能影响。研究发现,由X射线衍射图谱分析,合金主要由CaCu5型相、PuNi3型相及少量Pr5Co19型相组成,随着Nd含量的增加,合金物相晶胞参数和晶胞体积在逐渐降低。合金电极电化学测试显示,随着Nd含量的增加,La0.8-xNdxMg0.2Ni3.3Co0.5(x=0～0.15)合金电极电化学容量从370.5 mAh.g-1(x=0)增加到最大容量377.7 mAh.g-1(x=0.05),然后下降369.2 mAh.g-1(x=0.15);合金电极电化学容量经过100次循环的容量保持率S100从65.9%(x=0)增加到最大至72.8%(x=0.15);合金电极的高倍率性能HRD1200逐渐从83%(x=0)增加到88%(x=0.15),动力学测试分析结果显示合金高倍率性能是由电催化活性和氢在合金体内的扩散两个过程控制共同控制的。综合考虑,Nd取代量为0.15时,合金电极电化学性能较好。