Electroceramics
Encyclopedia
Electroceramics is a class of ceramic
materials used primarily for their electrical properties.
While ceramics have traditionally been admired and used for their mechanical, thermal and chemical stability, their unique electrical, optical and magnetic properties have become of increasing importance in many key technologies including communications, energy conversion and storage, electronics and automation. Such materials are now classified under electroceramics, as distinguished from other functional ceramics such as advanced structural ceramics.
Historically, developments in the various subclasses of electroceramics have paralleled the growth of new technologies. Examples include: ferroelectrics
- high dielectric capacitor
s, non-volatile memories; ferrite
s - data and information storage; solid electrolytes - energy storage and conversion; piezoelectrics - sonar; semiconducting oxides - environmental monitoring. Recent advances in these areas are described in the Journal of Electroceramics.
materials used for construction of ceramic capacitors include: zirconium barium titanate, strontium titanate
(ST), calcium titanate
(CT), magnesium titanate (MT), calcium magnesium titanate (CMT), zinc titanate
(ZT), lanthanum titanate (TLT), and neodymium titanate (TNT), barium zirconate (BZ), calcium zirconate (CZ), lead magnesium niobate (PMN), lead zinc niobate (PZN), lithium niobate
(LN), barium stannate (BS), calcium stannate (CS), magnesium aluminium silicate, magnesium silicate, barium tantalate, titanium dioxide
, niobium oxide
, zirconia, silica, sapphire
, beryllium oxide
, and zirconium tin titanate
Some piezoelectric materials can be used as well; the EIA Class 2 dielectric
s are based on mixtures rich on barium titanate
. In turn, EIA Class 1 dielectric
s contain little or no barium titanate.
(ITO), lanthanum-doped strontium titanate (SLT), yttrium-doped strontium titanate (SYT)
(YSZ), gadolinium-doped ceria (GDC), lanthanum strontium gallate magnesite(LSGM), beta alumina, beta" alumina
(PZT). Barium titanate
(BT), strontium titanate
(ST), quartz
,
and others are also used.
See :Category:Piezoelectric materials.
and Strontium carbonate
display magnetic properties. Lanthanum strontium manganite
exhibits colossal magnetoresistance
.
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
materials used primarily for their electrical properties.
While ceramics have traditionally been admired and used for their mechanical, thermal and chemical stability, their unique electrical, optical and magnetic properties have become of increasing importance in many key technologies including communications, energy conversion and storage, electronics and automation. Such materials are now classified under electroceramics, as distinguished from other functional ceramics such as advanced structural ceramics.
Historically, developments in the various subclasses of electroceramics have paralleled the growth of new technologies. Examples include: ferroelectrics
Ferroelectricity
Ferroelectricity is a property of certain materials which possess a spontaneous electric polarization that can be reversed by the application of an external electric field. The term is used in analogy to ferromagnetism, in which a material exhibits a permanent magnetic moment. Ferromagnetism was...
- high dielectric capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...
s, non-volatile memories; ferrite
Ferrite (magnet)
Ferrites are chemical compounds consisting of ceramic materials with iron oxide as their principal component. Many of them are magnetic materials and they are used to make permanent magnets, ferrite cores for transformers, and in various other applications.Many ferrites are spinels with the...
s - data and information storage; solid electrolytes - energy storage and conversion; piezoelectrics - sonar; semiconducting oxides - environmental monitoring. Recent advances in these areas are described in the Journal of Electroceramics.
Dielectric ceramics
DielectricDielectric
A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material, as in a conductor, but only slightly shift from their average equilibrium positions causing dielectric...
materials used for construction of ceramic capacitors include: zirconium barium titanate, strontium titanate
Strontium titanate
Strontium titanate is an oxide of strontium and titanium with the chemical formula SrTiO3. At room temperature, it is a centrosymmetric paraelectric material with a perovskite structure...
(ST), calcium titanate
Calcium titanate
Perovskite is a calcium titanium oxide mineral species composed of calcium titanate, with the chemical formula CaTiO3.The mineral was discovered in the Ural Mountains of Russia by Gustav Rose in 1839 and is named after Russian mineralogist Lev Perovski .It lends its name to the class of compounds...
(CT), magnesium titanate (MT), calcium magnesium titanate (CMT), zinc titanate
Zinc titanate
Zinc titanate, also known as zinc titanium oxide, is an inorganic compound which has the chemical formula of ZnTiO3. It is a white powder that is insoluble in water.-Toxicity:...
(ZT), lanthanum titanate (TLT), and neodymium titanate (TNT), barium zirconate (BZ), calcium zirconate (CZ), lead magnesium niobate (PMN), lead zinc niobate (PZN), lithium niobate
Lithium niobate
Lithium niobate is a compound of niobium, lithium, and oxygen. Its single crystals are an important material for optical waveguides, mobile phones, optical modulators and various other linear and non-linear optical applications.-Properties:...
(LN), barium stannate (BS), calcium stannate (CS), magnesium aluminium silicate, magnesium silicate, barium tantalate, titanium dioxide
Titanium dioxide
Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...
, niobium oxide
Niobium oxide
Niobium oxide may refer to:* Niobium monoxide , NbO* Niobium dioxide , NbO2* Niobium pentoxide , Nb2O5In addition to the above, other distinct oxides exist...
, zirconia, silica, sapphire
Sapphire
Sapphire is a gemstone variety of the mineral corundum, an aluminium oxide , when it is a color other than red or dark pink; in which case the gem would instead be called a ruby, considered to be a different gemstone. Trace amounts of other elements such as iron, titanium, or chromium can give...
, beryllium oxide
Beryllium oxide
Beryllium oxide , also known as beryllia, is an inorganic compound with the formula BeO. This colourless solid is a notable electrical insulator with a higher thermal conductivity than any other non-metal except diamond, and actually exceeds that of some metals. As an amorphous solid, beryllium...
, and zirconium tin titanate
Some piezoelectric materials can be used as well; the EIA Class 2 dielectric
EIA Class 2 dielectric
The EIA Class 2 dielectric materials are ceramic dielectric materials used in ceramic capacitors.The EIA Class 2 dielectrics in general are usually based on formulas with high content of barium titanate , possibly mixed with other dielectric electroceramics. Due to its piezoelectric properties,...
s are based on mixtures rich on barium titanate
Barium titanate
Barium titanate is the inorganic compound with the chemical formula BaTiO3. Barium titanate is a white powder and transparent as larger crystals...
. In turn, EIA Class 1 dielectric
EIA Class 1 dielectric
The EIA Class 1 dielectric materials are ceramic dielectric materials used in ceramic capacitors of small values The EIA Class 1 dielectric materials are ceramic dielectric materials used in ceramic capacitors of small values The EIA Class 1 dielectric materials are ceramic dielectric materials...
s contain little or no barium titanate.
Electronically conductive ceramics
Indium tin oxideIndium tin oxide
Indium tin oxide is a solid solution of indium oxide and tin oxide , typically 90% In2O3, 10% SnO2 by weight. It is transparent and colorless in thin layers while in bulk form it is yellowish to grey...
(ITO), lanthanum-doped strontium titanate (SLT), yttrium-doped strontium titanate (SYT)
Fast ion conductor ceramics
Yttria-stabilized zirconiaYttria-stabilized zirconia
Yttria-stabilized zirconia is a zirconium-oxide based ceramic, in which the particular crystal structure of zirconium oxide is made stable at room temperature by an addition of yttrium oxide...
(YSZ), gadolinium-doped ceria (GDC), lanthanum strontium gallate magnesite(LSGM), beta alumina, beta" alumina
Piezoelectric and ferroelectric ceramics
Commercially used piezoceramic is primarily lead zirconate titanateLead zirconate titanate
Lead zirconate titanate , also called PZT, is a ceramic perovskite material that shows a marked piezoelectric effect. PZT-based compounds are composed of the chemical elements lead and zirconium and the chemical compound titanate which are combined under extremely high temperatures. A filter is...
(PZT). Barium titanate
Barium titanate
Barium titanate is the inorganic compound with the chemical formula BaTiO3. Barium titanate is a white powder and transparent as larger crystals...
(BT), strontium titanate
Strontium titanate
Strontium titanate is an oxide of strontium and titanium with the chemical formula SrTiO3. At room temperature, it is a centrosymmetric paraelectric material with a perovskite structure...
(ST), quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
,
and others are also used.
See :Category:Piezoelectric materials.
Magnetic ceramics
Ferrites including Iron(III) OxideIron(III) oxide
Iron oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron oxide , which is rare, and iron oxide , which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe2O3 is the main...
and Strontium carbonate
Strontium carbonate
Strontium carbonate is the carbonate salt of strontium that has the appearance of a white or grey powder. It occurs in nature as the mineral strontianite.- Chemical properties :...
display magnetic properties. Lanthanum strontium manganite
Lanthanum strontium manganite
Lanthanum strontium manganite is an oxide ceramic material with the general formula La1-xSrxMnO3, where x describes the doping level and is usually in the range of 10-20%....
exhibits colossal magnetoresistance
Colossal magnetoresistance
Colossal magnetoresistance is a property of some materials, mostly manganese-based perovskite oxides, that enables them to dramatically change their electrical resistance in the presence of a magnetic field...
.
See also
- CeramicCeramicA ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
- Strontium titanateStrontium titanateStrontium titanate is an oxide of strontium and titanium with the chemical formula SrTiO3. At room temperature, it is a centrosymmetric paraelectric material with a perovskite structure...
- Barium titanateBarium titanateBarium titanate is the inorganic compound with the chemical formula BaTiO3. Barium titanate is a white powder and transparent as larger crystals...
- Lead zirconate titanateLead zirconate titanateLead zirconate titanate , also called PZT, is a ceramic perovskite material that shows a marked piezoelectric effect. PZT-based compounds are composed of the chemical elements lead and zirconium and the chemical compound titanate which are combined under extremely high temperatures. A filter is...