共查询到18条相似文献,搜索用时 156 毫秒
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以面心立方金属钯为研究对象,基于第一性原理中的局域密度近似理论(LDA),计算了不同晶格长度下的原子间内聚能并得到其原子内聚能曲线.通过陈-莫比乌斯晶格反演势理论,得到了精确的反演对势曲线.采用不同势函数对该曲线拟合,通过对拟合效果的对比和分析,提出了全局精度较高的双指数型势函数.同时,分别采用第一性原理方法,原子嵌入势(EAM)方法和反演势数据计算了钯的声子谱.比较声子谱曲线发现,曲线的变化趋势是相似的,说明反演势可以合理的反应原子间相互作用.并且反演势方法所需的计算时间明显少于EAM势方法,说明反演势方法在计算量上有明显优势.最后,计算了金属钯的热膨胀系数,弹性模量和格林乃森常数等物理量.计算结果与实验数据基本符合,表明构建的钯的反演势是准确有效的. 相似文献
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《贵金属》2017,(Z1)
以面心立方金属钯为研究对象,基于第一性原理中的局域密度近似理论(LDA),计算了不同晶格长度下的原子间内聚能并得到其原子内聚能曲线。通过陈-莫比乌斯晶格反演势理论,得到了精确的反演对势曲线。采用不同势函数对该曲线拟合,通过对拟合效果的对比和分析,提出了全局精度较高的双指数型势函数。同时,分别采用第一性原理方法,原子嵌入势(EAM)方法和反演势数据计算了钯的声子谱。比较声子谱曲线发现,曲线的变化趋势是相似的,说明反演势可以合理的反应原子间相互作用。并且反演势方法所需的计算时间明显少于EAM势方法,说明反演势方法在计算量上有明显优势。最后,计算了金属钯的热膨胀系数,弹性模量和格林乃森常数等物理量。计算结果与实验数据基本符合,表明构建的钯的反演势是准确有效的。 相似文献
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昆明贵金属研究所一室与化学制品车间合作,研究了从废铂铑(含少量铱)合金溶解液中,用萃取法分离提纯铂和铑的工艺流程.其方法要点是①用P204(二-2-乙基己基磷酸)萃取铑,分离铂和铑;②粗铑溶液通氯气氧化,用TAPO(三烷基氧化膦)萃取其中的微量铂、铱等贵金属杂质以纯化铑,离子交换除贱金属,甲酸还原,氢还原得纯铑;③粗铂溶液用氧化载体水解法提纯,氯化铵沉淀,锻烧得纯铂.原料溶液成分 相似文献
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描述了用熔丝法在铂点(1769℃)和铑点(1963℃)分度铱铑//铱热电偶的方法。分度是在以钽管和纯氧化铝管为内衬的碳管炉中,于大气气氛下进行。用0.01级直流电位差计测量热电势。分度的重现性为±2℃,误差为±3.6℃。用一等标准光学高温计检查了分度结果的可靠性,并用扫描电子显微镜检查了防碳污染的效果。 相似文献
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基于第一性原理计算研究了热电极铱和铱铑合金的能带结构和态密度。采用虚拟晶体近似方法建立了铱铑合金模型,通过搭建的试验平台测试了IrRh10-Ir热电偶和IrRh40-Ir热电偶的热电性能。结果表明,计算出的纯金属铱和铑的晶格常数与试验参数符合较好,铱铑合金具有良好的导体性能和结构稳定性。IrRh10-Ir热电偶和IrRh40-Ir热电偶具有良好的线性特性,灵敏度分别为2.7、5.6 μV/℃。有望将第一性原理计算分析应用于热电极材料的选择上。 相似文献
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ZHU Ping GU Guobang QU Zhiping HUANG Yanfei YAO Wenxue 《稀有金属(英文版)》2006,25(2):99-105
Platinum, palladium and rhodium of the raw feeds extracted and separated with a new sulfoxide extractant (MSO) were studied in the paper. The pilot test results showed that the percentage extractions are more than 99% for platinum and palladium in Pt-Pd feed, and the percentage strippings are 100% and 99.2% with HCl and ammonia, respectively. The ratio of palladium to platinum is 0.0016 in stripping platinum solution, and the ratio of platinum to palladium is 0.0020 in stripping palladium solution. The percentage extraction of platinum is 99% in Pt-Rh feed, and the percentage stripping is 100%. The ratio of rhodium to platinum is 0.0002 in stripping platinum solution. Therefore, platinum, palladium, and rhodium feeds are separated effectively with MSO. 相似文献
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为了适应饰品加工市场对高光亮镀铑添加剂国产替代进口的需要,在传统镀铑液配方及工艺的基础上,依据电化学原理,设计了全光亮镀铑添加剂的配方组合及工艺流程,并通过正交试验法对所获镀层的表观进行了评定,初步获得了一种新型全光亮镀铑添加剂.阐述了镀铑添加剂的作用机理,探索了最佳工艺用量.结果表明,采用本添加剂所得工艺配方简单,成本适中,操作方便,无毒无害,便于维护.在一定温度和电流密度条件下,所得镀铑层平整光亮,酷似白金,可作为仿白金装饰性镀层的理想工艺. 相似文献
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Jia-Ying Xie Li-Dong Teng Nan-Xian Chen S. Seetharaman 《Journal of Alloys and Compounds》2006,420(1-2):269-272
Based on the successful applications of lattice inversion method in many fields, the crystal structure and phase stability of Cr23C6 and Mn23C6 are investigated using the interatomic potentials obtained by lattice inversion method in this research. The calculated atomic coordinates and crystal parameters are in good agreement with the experimental results and the phase stability of Cr23C6 and Mn23C6 are tested by random atom shifts and global deformations. The calculated energy also indicates that the Cr23C6 is more stable than Mn23C6. 相似文献
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The phase stability, lattice constants and site preference of the disordered TbCu7-type rare-earth intermetallic compound PrCo7−xTx (T = Ti, Zr, Hf, Cu) are studied via interatomic pair potentials based on Chen's lattice inversion method. The results show that the ternary element T (T = Ti, Zr, Hf) can decrease the internal energy and stabilize the PrCo7 structure. The calculations also show that the T atoms preferentially occupy the 2e sites. The calculated lattice parameters and site preference are in agreement with the experimental data. The results indicate that the interatomic pair potentials are valid for studying some structural properties of the disordered intermetallics. 相似文献
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R dependence of electronic structure in perovskite type structure compounds, RBRh3 (R: Sc, Y and La)
Masaoki Oku Toetsu Shishido Masao Arai Kazuaki Wagatsuma Kazuo Nakajima 《Journal of Alloys and Compounds》2005,390(1-2):202-207
The electronic structures of perovskite type structure, RBRh3 (R: Sc, Y and La) were studied by X-ray photoelectron spectroscopy and calculation with full potential linearized augmented plane wave (FLAPW) method. As the lattice constant of the crystals increases with the atomic number of R, it can be discussed how the bond length between boron and rhodium atoms effect on the bonding character. The valence band XPS profiles of the samples are well coincided with the calculated profiles. The calculated electron density maps of the valence bands indicate the following. The charge transfer directions are from R to rhodium atoms and from boron to rhodium atoms. The bonds of RRh and BRh atoms have also covalent character. The covalency of RRh bond increases with the order of the atomic number of R atoms. On the other hand, the covalent bond of BRh decreases with the order atomic number. 相似文献
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贵金属铑和铱的电子结构和物理性质 总被引:1,自引:0,他引:1
应用纯金属单原子(OA)理论确定了面心立方(fcc)结构贵金属Rh和Ir的电子结构分别为[Kr](4dn)∧6.7400(5sc)∧0.0000(5sf)∧0.3600和[Xe](5dn)∧0.7100(5dc)∧7.2900(6sc)∧0.2700(6sf)∧0.7300,并计算了它们的热能曲线、晶格常数、结合能、弹性和膨胀系数随温度的变化,另外对其体心立方(bcc),密排六方(hcp)结构初态特征晶体和初态液体的电子结构进行了研究。从而提供了不同晶体结构Rh和Ir的结构参数和性能参数,为Rh和Ir金属元素及其相关材料的理论设计提供了完整的数据资料。 相似文献