File Name: crystalline and amorphous materials .zip
- Amorphous solid
- 12.1: Crystalline and Amorphous Solids
- On Structure and Properties of Amorphous Materials
Polymer Morphology. They have characteristic geometrical shape 2. It provides guidance for solubility and dissolution testing of amorphous dispersions.
Crystalline solids have regular ordered arrays of components held together by uniform intermolecular forces, whereas the components of amorphous solids are not arranged in regular arrays. The learning objective of this module is to know the characteristic properties of crystalline and amorphous solids. With few exceptions, the particles that compose a solid material, whether ionic, molecular, covalent, or metallic, are held in place by strong attractive forces between them. When we discuss solids, therefore, we consider the positions of the atoms, molecules, or ions, which are essentially fixed in space, rather than their motions which are more important in liquids and gases. The faces of crystals can intersect at right angles, as in galena PbS and pyrite FeS 2 , or at other angles, as in quartz.
A crystal or crystalline solid is a solid material whose constituents such as atoms , molecules , or ions are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. Examples of large crystals include snowflakes , diamonds , and table salt. Most inorganic solids are not crystals but polycrystals , i. Examples of polycrystals include most metals , rocks, ceramics , and ice. A third category of solids is amorphous solids , where the atoms have no periodic structure whatsoever.
Amorphous solid , any noncrystalline solid in which the atoms and molecules are not organized in a definite lattice pattern. Such solids include glass, plastic , and gel. Solids and liquids are both forms of condensed matter; both are composed of atoms in close proximity to each other. But their properties are, of course, enormously different. While a solid material has both a well-defined volume and a well-defined shape, a liquid has a well-defined volume but a shape that depends on the shape of the container. Stated differently, a solid exhibits resistance to shear stress while a liquid does not.
12.1: Crystalline and Amorphous Solids
On Structure and Properties of Amorphous Materials
Ayer, R. A Zr2Fe model alloy system was used to investigate the role of amorphous structure on corrosion resistance. Metal spun ribbons were prepared in single phase form in both the amorphous and crystalline states, with their respective atomic structures confirmed using X-ray diffraction and transmission electron microscopy.
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