英语翻译Owing to considerations of environmental protection and

英语翻译
Owing to considerations of environmental protection and human health,the adoption of lead-free solder has become an inevitable trend in the electronics industry.Among the various lead-free solder alloys,Sn–Ag–Cu (SAC) systems have been pro-posed as the most promising substitutes for tin–lead solder in reflow applications due to their relatively low melting temperature,generally superior mechanical properties,and relatively good solder abilities [1 –3].However,many issues with the SAC solders still
remain unresolved,such as the best composition,the large under-cooling in solidification,and the formation of large,brittle inter-metallic compounds (IMC) [4].Especially,alloys with high Ag content exhibit the formation of large Ag 3 Sn platelets at the solder-reaction layer interfaces,regardless of the kind of sub-strate [5].However,in meeting the demand for the miniaturization of integrated circuits,novel lead-free solders with better perfor-mance and reliability from interconnection BGA joints is needed.In order to further enhance the properties of Sn–Ag–Cu solder alloys,alloying elements such as transition metals,rare earths and nanoparticles were selected by addition into these alloys [6 –14].For e.g.,Pb-free solders doped with nano-sized,non-reacting,non-coarsening oxide dispersoids have been identified as potential materials that could provide higher microstructure stability and better mechanical properties than the conventional solders,such as in TiO2[7 ,8],A 2O3 [9 ,10],SiC [11] and ZrO2[12] .Another,adding minute amount of rare earth (RE) to the solder alloy is considered to be an effective way to improve the high temperature performance of solders [13 ,14].RE elements are the surface-active element,
which plays an important role in metallurgy of materials,such as
refinement of microstructure,alloying and purification of materials
and metamorphosis of inclusions.However,in the past decade,
China has tightened control of rare earth exports by introducing
export quotas that have been reduced each year,which is making
the rare earth elements relatively expensive[15] .

由于环境保护和人类健康的考虑,无铅焊料的采用已成为电子工业中的一种必然趋势.各种无铅焊料合金中Sn Ag,––铜（SAC）系统已经被提出作为锡铅焊料在回流–应用程序由于其相对较低的熔化温度最有前途的替代品,一般具有优越的机械性能,和相对良好的焊锡能力1–[ 3 ].然而,许多问题仍然与SAC焊料仍然没有得到解决,如最佳组成,冷却凝固在大,并形成大,脆性的金属间化合物（IMC）[ 4 ].特别是,高Ag含量合金焊料反应层的界面表现出大银3 Sn血小板的形成,无论子战略[ 5 ]的.然而,在满足集成电路的小型化的要求,新的无铅焊料具有更好的性能和可靠性的互连BGA焊点的需要.为了进一步提高锡银铜焊料合金––性能的合金元素,如过渡金属,稀土纳米粒子的选择加入到这些合金的6–[ 14 ].例如,无铅焊料掺杂纳米,无反应,无粗大氧化物弥散相已被确定为潜在的材料,可以提供更高的结构稳定性和更好的机械性能比传统的焊料,如TiO2 [ 7,8 ],[ 10 ] 9个2O3,氧化锆,碳化硅[ 11 ] [ 12 ].另外,添加微量的稀土（RE）的焊料合金被认为是提高焊料[ 13高温性能的有效途径,14 ].稀土元素是表面活性元素,它在冶金材料的一个重要的角色,如组织细化,合金化和净化材料变态的夹杂物.然而,在过去的十年,中国收紧稀土出口控制引入出口配额已被削减的每一年,这是稀土元素相对昂贵的[ 15 ].