摘要
评述了Au与全部稀土金属的相互作用与合金化行为。随着RE原子序数增大 ,RE在Au中固溶度增大 ,当RE与Au之间原子尺寸差小于 2 5%和电负性差低于 0 7时 ,RE在Au中固溶度可大于 1 0at% ;讨论了影响固溶度的因素。在Au -RE系中出现有 1∶6,1∶5,1∶4 ,…… 2∶1,7∶3 (RE∶Au) 13种化学计量化合物和约 2 0种晶体结构 ;中间相的简约转变温度与其平均原子体积收缩成反比趋势 ,且中间相原子体积收缩越大 ,其稳定性越高。Au-RE系中存在 4个共晶系 9种共晶反应 ,简约共晶温度与RE原子尺寸之间存在一个判据 :简约共晶温度随RE原子半径增大呈线性下降 ,但当RE原子半径达到约 0 175nm (即与Au相对尺寸差 2 1% )时 ,更大原子尺寸差不再影响液相线和共晶温度下降 ,简约共晶温度保持常数。以简约温度图讨论了平衡相的演变规律并可借以预测未知相的相关数据。
The interaction and alloying behavior between Au and RE metals were reviewed in present paper.With increase of atomic numbers of lanthanide,the solid solubilities of RE in Au increase, and the solid solubilities will be beyond 1 0at%RE when the differences of atomic sizes are less than 25% and that of the electronegaties are less than 0 7 between RE and Au.In Au-RE systems,there are 13 stoichiometrical intermetallic compounds with RE∶Au ratio 1∶6,1∶5,1∶4,……2∶1,7∶3 and so on. The compounds have about 20 crystal structures with prototype like Au 6Ho,Ag 3 6 Gd,MoSi 2,CsCl and so on. The reduced transformation temperatures of various intermediate phases are inversely proportional to their average atomic volume construction.The larger the atomic volume construction,the higher the stability of intermediate phase.There exist 4 eutectic systems with 9 eutectic reactions in Au-RE systems.A criterion exists between the reduced eutectic temperature (Teu/T Au )and the atomic radii (r R)of RE metals:the Teu/T A values dedine linearly with the increase of r R Value and keep essentially a constant when r RE values are larger than 0 175nm (namely the atomic size differences between RE and Au are larger than 21%).The dependences of reduced transformation temperatures of various equilibrium phase on the atomic numbers of RE metals were discussed through the reduced temperature maps.
出处
《贵金属》
CAS
CSCD
北大核心
2000年第1期42-51,共10页
Precious Metals
关键词
稀土
固溶度
金属间化合物
共晶反应
金
Gold,Rare-Earths,Solid solubility,Intermetallic compounds,Eutectic reaction
