Department of Mechanical Engineering and Materials Science, Rice University, Houston, Texas 77005, USA.
Nat Nanotechnol. 2010 Mar;5(3):218-24. doi: 10.1038/nnano.2010.4. Epub 2010 Feb 14.
The welding of metals at the nanoscale is likely to have an important role in the bottom-up fabrication of electrical and mechanical nanodevices. Existing welding techniques use local heating, requiring precise control of the heating mechanism and introducing the possibility of damage. The welding of metals without heating (or cold welding) has been demonstrated, but only at macroscopic length scales and under large applied pressures. Here, we demonstrate that single-crystalline gold nanowires with diameters between 3 and 10 nm can be cold-welded together within seconds by mechanical contact alone, and under relatively low applied pressures. High-resolution transmission electron microscopy and in situ measurements reveal that the welds are nearly perfect, with the same crystal orientation, strength and electrical conductivity as the rest of the nanowire. The high quality of the welds is attributed to the nanoscale sample dimensions, oriented-attachment mechanisms and mechanically assisted fast surface-atom diffusion. Welds are also demonstrated between gold and silver, and silver and silver, indicating that the technique may be generally applicable.
在纳米尺度上进行金属焊接，可能在电气和机械纳米器件的自下而上制造中发挥重要作用。现有的焊接技术采用局部加热，需要精确控制加热机制，并引入了损坏的可能性。已经证明了不加热（或冷焊接）的金属焊接，但仅在宏观长度尺度和大施加压力下。在这里，我们证明了直径在 3 至 10nm 之间的单晶金纳米线可以仅通过机械接触在几秒钟内冷焊在一起，并且施加的压力相对较低。高分辨率透射电子显微镜和原位测量表明，焊缝几乎是完美的，与纳米线的其余部分具有相同的晶体取向、强度和电导率。焊缝的高质量归因于纳米级样品尺寸、取向附生机制和机械辅助快速表面原子扩散。还在金和银之间以及银和银之间进行了焊接，表明该技术可能具有普遍适用性。
