Scrabble?! MICROSTRUCTURES

Definitions of MICROSTRUCTURES in various dictionaries:

Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by a microscope above 25× magnification. The microstructure of a material (such as metals, polymers, ceramics or composites) can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice. Microstructure at scales smaller than can be viewed with optical microscopes is often called nanostructure, while the structure in which individual atoms are arranged is known as crystal structure. The nanostructure of biological specimens is referred to as ultrastructure. A microstructure’s influence on the mechanical and physical properties of a material is primarily governed by the different defects present or absent of the structure. These defects can take many forms but the primary ones are the pores. Even if those pores play a very important role in the definition of the characteristics of a material, so does its composition. In fact, for many materials, different phases can exist at the same time. These phases have different properties and if managed correctly, can prevent the fracture of the material. The atoms and molecules comprising minerals and living matter are bound by six types of bonds with different intensities and properties. Examples include metallic bonds, covalent bonds, ionic bonds, and weak bonds. Among the weak bonds, there is a distinction between polar bonds or hydrophilic bonds (hydrogen bonds and van der Waals bonds) and nonpolar or hydrophobic bonds. From these properties will come the spatial form of the associated atoms and the molecules and then, at a larger scale, of the crystal, and finally of the organism as a whole. Metallic bonds are formed by the sharing of electrons in the outer layer of the atom in an electron cloud, where they are free and delocalized. This free-electron gas ensures the cohesion of the remaining cations and enables electrical conduction in metals and alloys. Covalent bonds are formed by the sharing of pairs of valence electrons in order to fill the outer electron shells of each atom. They are very strong bonds that are found in non-metals such as semiconductors, certain ceramics, polymers, and biological materials. Ionic bonds are formed by the transfer of an electron from one atom to the other. They are strong bonds that appear, for example, between a metal atom that has released an electron and a non-metal atom that has captured the free electron. After bonding, both atoms become charged. These bonds are found in minerals, ceramics, biological materials, and certain polymers (ionomers). Weak polar bonds are electrostatic and correspond to simple attractions between dipoles in compounds or molecules with inhomogeneous or polarizable charges. They act over long distance...