Essay About Properties Of Ceramics And Desirable Properties Of These Materials

Structures and Properties of Ceramics
Structures and Properties of Ceramics
Most ceramics are compounds between metallic
and nonmetallic elements for which the interatomic bonds are either totally
ionic, or predominantly ionic but having some covalent character
The term “ceramic” comes from the Greek word keramikos, which means “burnt stuff,” indicating
that desirable properties of these materials are normally achieved through
a high-temperature heat treatment process called firing.
Ceramic Structures
Because ceramics are composed of at least two elements, and often more, their crystal
structures are generally more complex than those for metals. The atomic bonding
in these materials ranges from purely ionic to totally covalent; many ceramics
exhibit a combination of these two bonding types, the degree of ionic character
being dependent on the electronegativities of the atoms.
CRYSTAL STRUCTURES
For those ceramic materials for which the atomic bonding is predominantly ionic,
the crystal structures may be thought of as being composed of electrically charged
ions instead of atoms. The metallic ions, or cations, are positively charged, because
they have given up their valence electrons to the nonmetallic ions, or
anions, which are negatively charged.
Two characteristics of the component ions
in crystalline ceramic materials influence the crystal structure: the magnitude of
the electrical charge