Gu Q F, Krauss G, Steurer W, Gramm F, Cervellino A
Laboratory of Crystallography, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland.
Phys Rev Lett. 2008 Feb 1;100(4):045502. doi: 10.1103/PhysRevLett.100.045502. Epub 2008 Jan 28.
We studied the compressibility of silver (10 nm) and gold (30 nm) nanoparticles, n-Ag and n-Au, suspended in a methanol-ethanol mixture by x-ray diffraction (XRD) with synchrotron radiation at pressures up to 30 GPa. Unexpectedly for that size, the nanoparticles show a significantly higher stiffness than the corresponding bulk materials. The bulk modulus of n-Au, K(0)=290(8) GPa, shows an increase of ca. 60% and is in the order of W or Ir. The structural characterization of both kinds of nanoparticles by XRD and high-resolution electron microscopy identified polysynthetic domain twinning and lamellar defects as the main origin for the strong decrease in compressibility.
我们通过同步辐射X射线衍射（XRD）研究了悬浮在甲醇 - 乙醇混合物中的银（10纳米）和金（30纳米）纳米颗粒（n - Ag和n - Au）在高达30吉帕压力下的压缩性。对于该尺寸的颗粒而言出人意料的是，纳米颗粒表现出比相应块状材料明显更高的硬度。n - Au的体积模量K(0)=290(8)吉帕，显示出约60%的增加，并且与钨或铱处于同一量级。通过XRD和高分辨率电子显微镜对这两种纳米颗粒进行的结构表征确定，多晶域孪晶和层状缺陷是压缩性大幅降低的主要原因。
