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稀土元素Ce对纯铜导电性及力学性能的影响 总被引:12,自引:0,他引:12
在纯铜中加入稀土元素Ce,研究不同含量Ce及不同保温时间对纯铜的导电性、抗拉强度、硬度、耐磨性等的影响.研究发现在纯铜中加入Ce起到净化、去杂质的作用,改善纯铜的导电性;也可使晶粒细化,改善纯铜的抗拉强度及其它力学性能.且熔炼时加入稀土后的保温时间要适当.在试验的条件下保温时间以30 min为宜,稀土Ce的最佳加入量w为0.02%. 相似文献
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研究了稀土Ce加入量对挤压态纯铜杆的电导率、硬度和疲劳性能的影响.结果表明,加入稀土元素Ce的挤压铜杆晶粒明显比未加稀土的细小,起到细化晶粒的作用;加入稀土Ce能提高纯铜的电导率和硬度,改善挤压纯铜杆的疲劳性能,稀土Ce加入量为0.04%时,挤压纯铜杆的综合性能最好. 相似文献
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稀土元素La和Ce在纯铜中的吸收率及其对组织的影响 总被引:2,自引:1,他引:1
选稀土元素La、Ce,并从稀土元素种类、熔点高低、加入方法、加入量、颗粒大小、浇注温度、保温时间等方面对稀土在纯铜中的吸收率进行了分析,从而找出影响稀土在纯铜中吸收率的因素,研究了铸态下稀土在纯铜中的分布位置、存在的状态以及形成的化合物等,分析了稀土在铜合金中的收得率及其对纯铜组织和性能的影响. 相似文献
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为了探索稀土元素在钢中的作用机理,分别研究混合稀土加入量La+Ce:36ppm、La+Ce:44ppm、La+Ce:51ppm与空白试样(La+Ce:0ppm)对含Nb结构钢强度及韧性的影响规律。通过拉伸试验、低温冲击试验以及SEM和EDS对材料性能和显微结构进行分析。结果表明:在Fe-0.07%C-0.025%Nb-x%(La+Ce)成分体系下,降Nb而添加适量混合La+Ce稀土化合物,随着La+Ce含量增加,断裂过程韧窝增大且逐渐加深,含Nb结构钢的屈服强度和抗拉强度呈增大趋势,且延伸率随着稀土含量和强度的增加未呈现大幅度下降趋势。说明混合La+Ce稀土化合物可以替代贵金属Nb元素来提升产品的强度指标。对于低温冲击试验,由断口形貌和四种成分系钢带试样吸收冲击能量对比得出,在含Nb结构钢中,混合La+Ce稀土加入量为36ppm时,变质钢中的夹杂物形成有效的LaCeO2S析出粒子阻碍断裂过程裂纹扩展,-40℃和-60℃的低温冲击韧性最优。 相似文献
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稀土元素对工业纯铝导电性的影响 总被引:16,自引:4,他引:12
研究了稀土元素对工业纯铝导电性的影响。结果表明:混合稀土对工业纯铝的导电性没有改善作用;在一定的数量范围内纯稀土元素镧、铈的加入,对铝的常温导电性有一定的改善作用,高温时则使电阻率略微上升。还对镧、铈降低铝常温电阻率的机理作了初步的探讨。 相似文献
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AgSnO_2触头材料中的SnO_2是一种高硬度并且近乎绝缘的宽禁带半导体材料,使得触头材料的电阻增大,加工成型困难,用稀土元素La、Ce、Y掺杂SnO_2可以改善触头材料的性能。基于密度泛函理论的第一性原理,运用平面波超软赝势法,对SnO_2和掺杂稀土元素的SnO_2进行电子结构和弹性常数的计算。结果表明,掺杂可以提高导电性能、降低SnO_2的硬度,其中添加稀土元素La的SnO_2的硬度最小;Y掺杂SnO_2的硬度较小、导电性最高且普适弹性各向异性的指数最小。 相似文献
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The mixtures of LiBH4 with halides of Ce or La in a molar ratio of 3:1 were investigated to explore their hydrogen storage properties. The ball milling of LiBH4 with chloride of Ce or La yielded Ce(BH4)3 and La(BH4)3, while fluoride of Ce or La did not react with LiBH4 during extended ball milling at room temperature. The dehydrogenation temperatures of the ball-milled mixtures were reduced to 220-320 °C, which were much lower than that of pure LiBH4. The diborane emission during hydrogen release was observed at a low level. The dehydrogenation temperature is found to be affected by the composition of rare earth halides, but less influenced by ball milling time. The endothermic dehydrogenation reactions produced lithium halides, hydrides and borides of the corresponding rare earth element. Moreover, the LiBH4 + 1/3(Ce, La)(Cl, F)3 showed partial reversibility through the formation of an unknown borohydride, allowing for a potential hydrogen storage system. 相似文献
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The effect of rare earth elements Ce and La on the evolution behavior of inclusions in HRB400E steel was studied through experimental observations and thermodynamic calculations. Neutral salt spray corrosion experiments were also conducted to investigate the effect of Ce–La on the corrosion resistance of steel. The results showed that the typical inclusions in steel without rare earth were MnS and MnO–SiO2. A small amount of Mn–Si–O–S inclusions was also observed. After adding rare earth, the typical inclusions were transformed into isolated (Ce,La)2O2S, (Ce,La)2O3 + MnS, and (Ce,La)2O2S + MnS complex inclusions. The thermodynamic calculations indicated that the rare earth elements in molten steel preferentially reacted with MnO–SiO2 inclusions and dissolved oxygen and sulfur to form (Ce,La)2O3 and (Ce,La)2O2S. Small amounts of [S] and [Mn] adhered to the surface of the nucleated rare earth inclusions to form complex inclusions. After Ce–La treatment, the corrosion rate of the steel decreased from 3.491 to 1.992 mm year−1, and the corrosion resistance was improved. The change in corrosion behavior is due to the modification of the inclusions into rare earth inclusions with good compatibility with the steel matrix. 相似文献
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采用Ce﹑Pr和Nd少量混合稀土部分替代La,采用感应熔炼及高温退火工艺制备(La0.7Ce0.1PrxNd0.2-x)0.67Mg0.33Ni3.0(x=0,0.1,0.2)系列贮氢合金。结果表明,与La0.67Mg0.33Ni3.0合金相比较,混合稀土元素加入后对合金的相组成没有本质影响,(La0.7Ce0.1PrxNd0.2-x)0.67Mg0.33Ni3.0(x=0,0.1,0.2)合金微观组织由主相PuNi3型结构与LaMgNi4第二相组成;随混合稀土加入和Pr含量x的增加,PuNi3型相晶体结构的晶胞体积和a轴减小,但c轴及轴比c/a增大。电化学性能测试结果表明,用混合稀土Ce﹑Pr和Nd少量替代La后均能明显改善合金的综合电化学性能,合金的电化学容量与La0.67Mg0.33Ni3.0合金(392.0mAh/g)比较虽略有下降,但随Pr含量x的增加,混合稀土合金电极容量有所提高(384mAh/g);经100次循环后,混合稀土合金电极容量保持率从La0.67Mg0.33Ni3.0合金时的64%提高到82%~83%,其高倍率放电性能则从78.4%提高到了89%~91%。 相似文献