Nanoglasses: a new kind of noncrystalline materials
نویسنده
چکیده
Nanoglasses are a new class of noncrystalline solids. They differ from today's glasses due to their microstructure that resembles the microstructure of polycrystals. They consist of regions with a melt-quenched glassy structure connected by interfacial regions, the structure of which is characterized (in comparison to the corresponding melt-quenched glass) by (1) a reduced (up to about 10%) density, (2) a reduced (up to about 20%) number of nearest-neighbor atoms and (3) a different electronic structure. Due to their new kind of atomic and electronic structure, the properties of nanoglasses may be modified by (1) controlling the size of the glassy regions (i.e., the volume fraction of the interfacial regions) and/or (2) by varying their chemical composition. Nanoglasses exhibit new properties, e.g., a Fe90Sc10 nanoglass is (at 300 K) a strong ferromagnet whereas the corresponding melt-quenched glass is paramagnetic. Moreover, nanoglasses were noted to be more ductile, more biocompatible, and catalytically more active than the corresponding melt-quenched glasses. Hence, this new class of noncrystalline materials may open the way to technologies utilizing the new properties.
منابع مشابه
Extending X-ray crystallography to allow the imaging of noncrystalline materials, cells, and single protein complexes.
In 1999, researchers extended X-ray crystallography to allow the imaging of noncrystalline specimens by measuring the X-ray diffraction pattern of a noncrystalline specimen and then directly phasing it using the oversampling method with iterative algorithms. Since then, the field has evolved moving in three important directions. The first is the 3D structural determination of noncrystalline mat...
متن کاملJu l 1 99 8 A molecular - dynamics study of ductile and brittle fracture in model noncrystalline solids
A molecular-dynamics study of ductile and brittle fracture in model noncrystalline solids Abstract Molecular-dynamics simulations of fracture in model amorphous solids are shown to exhibit brittle or ductile behavior depending on small changes in interatomic potential. Yet, simulations of these two model solids under pure shear reveal no significant difference in their ultimate yield stress. To...
متن کاملA nanoglass alloying immiscible Fe and Cu at the nanoscale.
Synthesized from ultrafine particles with a bottom-up approach, nanoglasses are of particular importance in pursuing unique properties. Here, we design a metallic nanoglass alloy from two components of ∼Cu64Sc36 and ∼Fe90Sc10 nanoglasses. With nanoalloying mutually immiscible Fe and Cu, the properties of the nanoglass alloys can be tuned by varying the proportions of the ∼Fe90Sc10 component. Th...
متن کاملBeyond crystallography: diffractive imaging using coherent x-ray light sources.
X-ray crystallography has been central to the development of many fields of science over the past century. It has now matured to a point that as long as good-quality crystals are available, their atomic structure can be routinely determined in three dimensions. However, many samples in physics, chemistry, materials science, nanoscience, geology, and biology are noncrystalline, and thus their th...
متن کاملDensity measurements of noncrystalline materials at high pressure with diamond anvil cell.
We describe an x-ray absorption method for in situ density measurement of non-crystalline materials in the diamond anvil cell using a monochromatic synchrotron x-ray microbeam. Sample thickness, which is indispensable in the absorption method, can be determined precisely by extrapolating the thickness profile of the gasket obtained by x-ray absorption and diffraction measurements. Diamond defor...
متن کامل