Portal Lotan, Polishchuk Iryna, Koifman Khristosov Maria, Katsman Alexander, Pokroy Boaz
Department of Materials Science and Engineering, Technion-Israel Institute of Technology, 32000 Haifa, Israel.
Department of Materials Science and Engineering, Technion-Israel Institute of Technology, 32000 Haifa, Israel;
Proc Natl Acad Sci U S A. 2021 Sep 28;118(39). doi: 10.1073/pnas.2107930118.
Dislocations in metals affect their properties on the macro- and the microscales. For example, they increase a metal's hardness and strength. Dislocation outcrops exist on the surfaces of such metals, and atoms in the proximity of these outcrops are more loosely bonded, facilitating local chemical corrosion and reactivity. In this study, we present a unique autocatalytic mechanism by which a system of inorganic semiconducting gold(I) cyanide nanowires forms within preexisting dislocation lines in a plastically deformed Au-Ag alloy. The formation occurs during the classical selective dealloying process that forms nanoporous Au. Nucleation of the nanowire originates at the surfaces of the catalytic dislocation outcrops. The nanowires are single crystals that spontaneously undergo layer-by-layer one-dimensional growth. The continuous growth of nanowires is achieved when the dislocation density exceeds a critical value evaluated on the basis of a kinetic model that we developed.
金属中的位错会在宏观和微观尺度上影响其性能。例如，它们会增加金属的硬度和强度。这些金属的表面存在位错露头，这些露头附近的原子键合较松散，有利于局部化学腐蚀和反应活性。在本研究中，我们提出了一种独特的自催化机制，通过该机制，无机半导体氰化亚金（I）纳米线系统在塑性变形的金 - 银合金中预先存在的位错线内形成。这种形成过程发生在形成纳米多孔金的经典选择性脱合金过程中。纳米线的成核起源于催化位错露头的表面。这些纳米线是单晶，会自发地进行逐层一维生长。当位错密度超过我们根据所开发的动力学模型评估的临界值时，纳米线就能实现持续生长。
