Nano-metallic materials: Advances and challenges

September 26, 2022

More than 40 years ago, scientists realized that disordered structures in real materials cannot be ignored. Many of the NEWLY discovered PHYSICAL EFFECTS, SUCH as certain phase transitions, quantum SIZE EFFECTS, and RELATED TRANSPORT PHENOMENA, OCCUR ONLY in ordered solids containing defects. In fact, if the crystal area of polycrystal characteristic scale (grain diameter or domain or film thickness) reaches a certain characteristic length (such as electronic wavelength, the mean free path, coherent length, correlation length, etc.), the performance of the materials will not only depend on the lattice in the interaction of the atom, is influenced by the reduction of its dimension, scale and High density defects control. In view of this, HGleitCr believes that if polycrystals of nanometer size can be synthesized, that is, materials composed mainly of non-coherent interfaces [e.g., 50%(in vol.) of non-co-cultivated grain boundaries and 50%(in vol.) of crystals], Its structure will be significantly different from ordinary polycrystal (grain size larger than LMM) or glass (order less than 2nm), which is called "nanocrystalline materials". Later, the crystal region or other materials whose characteristic length is in the nanometer range (less than 100NN) are broadly defined as "nanomaterials" or "nanostructured materials". Due to their unique microstructure and exotic properties, nanomaterials have attracted great attention from the scientific community and become a research hotspot worldwide. Their fields involve physics, chemistry, biology, microelectronics and many other disciplines. At present, the broad definition of nanomaterials mainly includes:

L) Clean or coat surface metal, semiconductor or polymer films;

2) Artificial superlattices and quantum structures;

3) semi-crystalline polymer and polymer mixture;

4) nanocrystals and nanocrystals;

5) Nanocomposites composed of metallic bonds, covalent bonds or molecular components.

Author:

Mr. Dongxu Li

E-mail:

JL11tech@163.com

Phone/WhatsApp:

+8618043212860