Ceramics And Electrical Conductivity

Most of ceramic materials are dielectric materials having very low electric conductivity but supporting electrostatic field.

Ceramics and electrical conductivity.

This is due to the fact that charge transport mechanisms are frequency dependent. Most ceramics resist the flow of electric current and for this reason ceramic materials such as porcelain have traditionally been made into electric insulators. Some ceramics however are excellent conductors of electricity. Looking at the values quoted in various handbooks papers and data sheets two things are observed.

This is due to their good structural properties together with excellent electrical conductivity when doped with aliovalent cations such as mg 2 ca 2 or particularly y 3 1. Electrical conductivity of ceramics varies with the frequency of field applied and also with temperature. In practice it is primarily the result impurities and lattice defects and may vary widely from batch to batch. Anderson discusses the properties and characteristics of this unique class of ceramics which allow them to be utilized both as electrical insulators as well as electrical conductors.

The electrical conductivity of ceramic substrates is extremely low. They withstand chemical erosion that occurs in other materials subjected to acidic or caustic environments. Most of these conductors are advanced ceramics modern materials whose properties are modified through precise control over their fabrication from powders into products. Some elements such as carbon or silicon maybe considered ceramics ceramic materials are brittle hard strong in compression and weak in shearing and tension.

Zirconia ceramics are among the most prominent engineering ceramics. Electrical conductivity in metals is a result of the movement of electrically charged particles. All of these factors are closely related to the chemical properties of the constituent elements and this provides a convenient way to classify the materials into groups having related properties. The problem with the thermal conductivity of ceramics is the dependence on the composition grain size and manufacturing process which make it rather difficult to obtain a reliable value from literature only.

As the temperature increases the ratio of thermal to injected carriers increases. Also it is observed that the metallic nanofluids show less conductivity enhancement than oxides which is counterintuitive keeping the higher conductivity of metals into consideration. The atoms of metal elements are characterized by the presence of valence electrons which are electrons in the outer shell of an atom that are free to move about. It is observed from the figure that the electrical conductivity increases linearly with concentration for ceramic cuo and al 2 o 3 nanofluids and increases in a nonlinear fashion for metallic nanofluids cu.