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  HOME > Characteristics of Fine Ceramics > Electrical - Dielectricity 
Electrical
Insulation Dielectricity Conductivity Piezoelectricity Magnetism Superconductivity
Accumulation of Electricity

When voltage is applied to electrodes attached to opposite sides of an insulating ceramic, they exhibit electricity-accumulating properties. These insulators are said to be dielectric.

An insulator that can accumulate a volume of electricity exceptionally well is called ferroelectric. Some Fine Ceramics (also known as “advanced ceramics”) display this property. Consequently, ceramic has become an indispensable material for producing capacitors and electronic components that are widely used in products such as computers, televisions and mobile phones. Capacitors serve as "traffic controllers" within an electronic circuit by conducting electricity to certain parts, temporarily blocking electricity, or blocking only certain types of electrical signals.

 

Application: Ceramic capicitors.

Description
Dielectricity

Electricity, by definition, is the movement of electrons within the molecules of a material. Although electrons can move freely within conductors, they cannot do so within insulators. When a direct current voltage is applied to an insulator, electrons do not separate from molecules, and are divided by an electrical charge (positive or negative) induced at both ends of the material.

In addition, ions themselves may move. Materials in which electrical charges appear at both ends are called dielectric substances. Dielectricity is measured by the relative dielectric constant, a value representing the ratio of the dielectric constant of the material in question and that of a vacuum. The dielectric constant of quartz is 3.8, while that of sapphire (main component: oxidized aluminum) is 9.4. The dielectric constant of barium titanate, a ferroelectric material, is as high as 4,000 to 5,000.

Relative Dielectric Constants

Quartz
(SiO2)
3.8   
Sapphire
(Al2O3)
9.4   
Barium Titanate
(BaTiO3)
4,000 - 5,000   
   
 
The term "Fine Ceramics" is interchangeable with "advanced ceramics," "technical ceramics" and "engineered ceramics." Use varies by region and industry.
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