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Encyclopedia > Ceramic
Fixed Partial Denture, or "Bridge"

The word ceramic is derived from the Greek word κεραμικός (keramikos). The term covers inorganic non-metallic materials which are formed by the action of heat. Up until the 1950s or so, the most important of these were the traditional clays, made into pottery, bricks, tiles and the like, along with cements and glass. Clay based ceramics are described in the article on pottery. A composite material of ceramic and metal is known as cermet. The word ceramic can be an adjective, and can also be used as a noun to refer to a ceramic material, or a product of ceramic manufacture. Ceramics is a singular noun referring to the art of making things out of ceramic materials. The technology of manufacturing and usage of ceramic materials is part of the field of ceramic engineering. This article is about artwork made out of clay. ... ImageMetadata File history File links Download high resolution version (2061x1261, 1106 KB) My name is Russ Wagoner. ... ImageMetadata File history File links Download high resolution version (2061x1261, 1106 KB) My name is Russ Wagoner. ... Categories: Stub | Dentistry ... Inorganic chemistry is the branch of chemistry concerned with the properties and reactions of inorganic compounds. ... For other uses, see Clay (disambiguation). ... Unfired green ware pottery on a traditional drying rack at Conner Prairie living history museum. ... For other uses, see Brick (disambiguation). ... Mission, or barrel, roof tiles A tile is a manufactured piece of hard-wearing material such as ceramic, stone, porcelain, metal or even glass. ... For other uses, see Cement (disambiguation). ... This article is about the material. ... For other uses, see Clay (disambiguation). ... Unfired green ware pottery on a traditional drying rack at Conner Prairie living history museum. ... A cloth of woven carbon fiber filaments, a common element in composite materials Composite materials (or composites for short) are engineered materials made from two or more constituent materials with significantly different physical or chemical properties and which remain separate and distinct on a macroscopic level within the finished structure. ... This article is about metallic materials. ... A Cermet is a composite material composed of ceramic (cer) and metallic (met) materials. ... Ceramic engineering is the technology of manufacturing and usage of ceramic materials. ...


Many ceramic materials are hard, porous and brittle. The study and development of ceramics includes methods to mitigate problems associated with these characteristics, and to accentuate the strengths of the materials as well as to investigate novel applications.


The American Society for Testing and Materials (ASTM) defines a ceramic article as “an article having a glazed or unglazed body of crystalline or partly crystalline structure, or of glass, which body is produced from essentially inorganic, non-metallic substances and either is formed from a molten mass which solidifies on cooling, or is formed and simultaneously or subsequently matured by the action of the heat.”[1] ASTM International is an international voluntary standards organization that develops and produces technical standards for materials, products, systems and services. ... Crystal (disambiguation) Insulin crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ...

Contents

Types of ceramic materials

For convenience ceramic products are usually divided into four sectors, and these are shown below with some examples:

See also Wikimedia Commons has multimedia related to: Bricks Masonry Brickwork Ceramics Fire brick In role-playing games, a brick is a character whose main useful skill is being able to take a great deal of damage (usually physical damage) and act as a shield for weaker allies. ... Pipe is a tube or hollow cylinder for the conveyance of fluid. ... A hardwood floor (parquetry) is a popular feature in many houses. ... Mission, or barrel, roof tiles A tile is a manufactured piece of hard-wearing material such as ceramic, stone, porcelain, metal or even glass. ... The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ... Charcoal Kilns, California Gold Kiln, Victoria, Australia Hop kiln. ... For other uses, see Steel (disambiguation). ... Tableware are the cutlery, eating utensils, glassware, and dishware used when setting a table for dining. ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... Rocket Nozzle A nozzle is a mechanical device designed to control the characteristics of a fluid flow as it exits from an enclosed chamber into some medium. ... For other uses, see Ballistics (disambiguation). ... Health science is the discipline of applied science which deals with human and animal health. ... The term implant has different meanings: in Scientology, see Implant (Scientology) in medicine, see prosthesis This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... A Siemens steam turbine with the case opened. ... For other uses, see Missile (disambiguation). ...

Examples of structural ceramics

For other uses, see Brick (disambiguation). ... Mission, or barrel, roof tiles A tile is a manufactured piece of hard-wearing material such as ceramic, stone, porcelain, metal or even glass. ... PIPE can refer to PIPE (explosive) PIPE Networks Private Investment in Public Equity (PIPE) Physical Interface for PCI Express (PIPE) For other meanings, see also pipe. ...

Examples of whiteware ceramics

Bone china is type of porcelain body first developed in the Britain in which calcined ox bone, bone ash, is a major constituent. ... Earthenware is a common ceramic material, which is used extensively for pottery tableware and decorative objects. ... For other uses, see Quartz (disambiguation). ... This article does not cite any references or sources. ... “Fine China” redirects here. ... Kaolin Kaolinite (Aluminium Silicate Hydroxide) Kaolinite is a mineral with the chemical composition Al2Si2O5(OH)4. ... A Staffordshire stoneware plate from the 1850s with transferred copper print - (From the home of JL Runeberg) Stoneware is a category of clay and a type of ceramic distinguished primarily by its firing and maturation temperature (from about 1200°C to 1315 °C). ...

Classification of technical ceramics

Technical ceramics can also be classified into three distinct material categories:

Each one of these classes can develop unique material properties An oxide is a chemical compound containing at least one oxygen atom and other elements. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... Zirconia (ZrO2) is a white crystalline oxide of zirconium. ... Calcium carbide. ... The boride ion is B3- (a boron atom plus three electrons). ... Definition The nitride ion is very very gay and retarded A nitride (compound) is a compound that has nitrogen with more electropositive elements. ... A silicide is a compound that has silicon with more electropositive elements. ... Look up composite in Wiktionary, the free dictionary. ...


Examples of technical ceramics

Barium titanate is an oxide of barium and titanium with the chemical formula BaTiO3. ... Strontium titanate is an oxide of strontium and titanium with the chemical formula SrTiO3. ... This article or section is in need of attention from an expert on the subject. ... In engineering, electromechanics combines the sciences of electromagnetism of electrical engineering and mechanics. ... A transducer is a device, usually electrical or electronic, that converts one type of energy to another. ... See Capacitor (component) for a discussion of specific types. ... Ferroelectric RAM (FRAM or FeRAM) is a type of non-volatile computer memory, similar to EEPROM but based on electric field orientation and with near-unlimited number (exceeding 1010 for 5V devices and even more for 3. ... A crystallite is a domain of solid-state matter that has the same structure as a single crystal. ... Positive Temperature Coefficient (PTC) referers to materials that when temperature is raised, the electrical resistance increases sharply. ... A heating element converts electricity into heat through the process of Joule heating. ... Bismuth strontium calcium copper oxide, or BSCCO, chemical formula Bi2Sr2CanCun+1O2n+6, is a family of high-temperature superconductors. ... Unsolved problems in physics: Why do certain materials exhibit superconductivity at temperatures much higher than 50 kelvins? The term high-temperature superconductor was initially employed to designate the new family of cuprate-perovskite ceramic materials discovered by J.G. Bednorz and K.A. Müller in 1986. ... Boron carbide (chemical formula B4C) is an extremely hard ceramic material used in tank armor, bulletproof vests, and numerous industrial applications. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Standard atomic weight 10. ... For other uses, see Carbon (disambiguation). ... It has been suggested that Small-arms protective insert be merged into this article or section. ... Military vehicles are commonly armoured to withstand the impact of shrapnel, bullets or shells, protecting the soldiers inside from enemy fire. ... Boron nitride is a binary chemical compound, consisting of equal proportions of boron and nitrogen, with formula BN. Structurally, it is isoelectronic to carbon and takes on similar physical forms: a hexagonal, graphite-like one, and a cubic, diamond-like one. ... Two or more molecular entities (atoms, molecules, ions) are described as isoelectronic if they have the same number of valence electrons and the same structure (number and connectivity of atoms), but may differ in the elements involved. ... For other uses, see Graphite (disambiguation). ... A lubricant (colloquially, lube) is a substance (often a liquid) introduced between two moving surfaces to reduce the friction and wear between them. ... This article is about the mineral. ... A stack of ferrite magnets Ferrites are electrically non-conductive ferrimagnetic ceramic compound materials, consisting of various mixtures of iron oxides such as Hematite (Fe2O3) or Magnetite (Fe3O4) and the oxides of other metals. ... For other uses, see Iron (disambiguation). ... In physics, a ferrimagnetic material is one in which the magnetic moment of the atoms on different sublattices oppose as in antiferromagnetism but the opposing moments are unequal and a spontaneous magnetization remains. ... A magnetic core is the core of an electromagnet or inductor. ... For other uses, see Transformer (disambiguation). ... A 16×16 cm area core memory plane of 128×128 bits, i. ... Lead zirconium titanate (PZT, also Lead zirconate titanate) is a ceramic perovskite material that shows a marked piezoelectric effect - that is, it develops a voltage difference across two of its faces when compressed, and ferroelectric effect. ... Magnesium diboride (MgB2) is an inexpensive and simple superconductor that can be synthesized by high temperature reaction between boron and magnesium (in the liquid or gaseous state). ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Unconventional superconductors are materials that display superconductivity but that do not conform to BCS theory or its extensions. ... Sialon ceramics are a specialist class of high temperature refractory materials, with high strength (including at temperature), good thermal shock resistance and exceptional resistance to wetting or corrosion by molten non-ferrous metals, compared to other refractory materials such as, for example, alumina. ... Sialon ceramics are a specialist class of high temperature refractory materials, with high strength (including at temperature), good thermal shock resistance and exceptional resistance to wetting or corrosion by molten non-ferrous metals, compared to other refractory materials such as, for example, alumina. ... Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Silicon carbide (SiC) is a ceramic compound of silicon and carbon that is manufactured on a large scale for use mainly as an abrasive but also occurs in... Not to be confused with Silicone. ... A susceptor is a material used for its ability to absorb electromagnetic energy. ... In metallurgy, refraction is a property of metals that indicates their ability to withstand heat. ... Silicon nitride (Si3N4) is hard, solid substance, that can be obtained by direct reaction between silicon and nitrogen in high temperatures. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... An abrasive is a material, often a mineral, that is used to shape or finish (see metal polishing and wood finishing) a workpiece through rubbing which leads to part of the workpiece being worn away. ... An Egyptian carved and glazed steatite scarab amulet. ... // Definition An Insulator is a material or object which resists the flow of heat (thermal insulators) or electric charge (electrical insulators). ... Uranium oxide is an oxide of the element uranium. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... Nuclear Fuel Process A graph comparing nucleon number against binding energy Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... Core of a small nuclear reactor used for research. ... Yttrium barium copper oxide, often abbreviated YBCO, is a chemical compound with the formula YBa2Cu3O7. ... General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Standard atomic weight 88. ... For other uses, see Barium (disambiguation). ... Copper has played a significant part in the history of mankind, which has used the easily accessible uncompounded metal for nearly 10,000 years. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... A magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen. ... Zinc oxide is a chemical compound with formula ZnO. It is nearly insoluble in water but soluble in acids or alkalis. ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... A semiconductor is a solid whose electrical conductivity is in between that of a conductor and that of an insulator, and can be controlled over a wide range, either permanently or dynamically. ... A varistor is an electronic component with a significant non-ohmic current-voltage characteristic. ... Zirconium dioxide (ZrO2), sometimes known as zirconia, is a white crystalline oxide of zirconium. ... In its most common usage, the term phase change indicates that a substance has changed among the three classical phases of matter: solid, liquid and gas. ... This article or section does not cite its references or sources. ... Fast ion conductors,also known as solid electrolytes, conduct due to the movement of ions through voids in their crystal lattice. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... Metastability is the ability of a non-equilibrium state to persist for a long period of time. ... ... A ceramic knife is a knife made out of very hard ceramic, often zirconia. ...

Properties of ceramics

Mechanical properties

Ceramic materials are usually ionic or covalently-bonded materials, and can be crystalline or amorphous. A material held together by either type of bond will tend to fracture before any plastic deformation takes place, which results in poor toughness in these materials. Additionally, because these materials tend to be porous, the pores and other microscopic imperfections act as stress concentrators, decreasing the toughness further, and reducing the tensile strength. These combine to give catastrophic failures, as opposed to the normally much more gentle failure modes of metals. Electron configurations of lithium and fluorine. ... Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ... For other uses, see Crystal (disambiguation). ... Wax and paraffin are amorphous. ... For other uses, see Fracture (disambiguation). ... In physics and materials science, plasticity is a property of a material to undergo a non-reversible change of shape in response to an applied force. ... In materials science and metallurgy, toughness is the resistance to fracture of a material when stressed. ... Porosity is a measure of the void spaces in a material, and is measured as a fraction, between 0–1, or as a percentage between 0–100%. The term porosity is used in multiple fields including manufacturing, earth sciences and construction. ... A stress concentration is a phenomenon encounterered in mechanical engineering where an object under load has higher than average local stresses due to its shape. ... Tensile strength isthe measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. ... Catastrophic failure is a sudden and total failure of some system from which recovery is impossible. ... Failure mode The Manner by whick a failure is observed; it generally describes the way the failure occurs and its impact on equipment operation. ...


These materials do show plastic deformation. However, due to the rigid structure of the crystalline materials, there are very few available slip systems for dislocations to move, and so they deform very slowly. With the non-crystalline (glassy) materials, viscous flow is the dominant source of plastic deformation, and is also very slow. It is therefore neglected in many applications of ceramic materials. For other uses, see Plasticity. ... In materials science, a dislocation is a crystallographic defect, or irregularity, within a crystal structure. ... For other uses, see Viscosity (disambiguation). ...


Electrical properties

Semiconductors

There are a number of ceramics that are semiconductors. Most of these are transition metal oxides that are II-VI semiconductors, such as zinc oxide. A semiconductor is a solid whose electrical conductivity is in between that of a conductor and that of an insulator, and can be controlled over a wide range, either permanently or dynamically. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... Zinc oxide is a chemical compound with formula ZnO. It is nearly insoluble in water but soluble in acids or alkalis. ...


While there is talk of making blue LEDs from zinc oxide, ceramicists are most interested in the electrical properties that show grain boundary effects. External links LEd Category: TeX ... Zinc oxide is a chemical compound with formula ZnO. It is nearly insoluble in water but soluble in acids or alkalis. ...


One of the most widely used of these is the varistor. These are devices that exhibit the property that resistance drops sharply at a certain threshold voltage. Once the voltage across the device reaches the threshold, there is a breakdown of the electrical structure in the vicinity of the grain boundaries, which results in its electrical resistance dropping from several megohms down to a few hundred ohms. The major advantage of these is that they can dissipate a lot of energy, and they self reset — after the voltage across the device drops below the threshold, its resistance returns to being high. Depletion Region of an NMOS The threshold voltage of a MOSFET is usually defined as the gate voltage where a depletion region forms in the substrate (body) of the transistor. ... The term electrical breakdown has several similar but distinctly different meanings. ... Galvanized surface with visible crystallites (grains) of zinc. ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... The ohm (symbol: Ω) is the SI unit of electric resistance. ...


This makes them ideal for surge-protection applications. As there is control over the threshold voltage and energy tolerance, they find use in all sorts of applications. The best demonstration of their ability can be found in electrical substations, where they are employed to protect the infrastructure from lightning strikes. They have rapid response, are low maintenance, and do not appreciably degrade from use, making them virtually ideal devices for this application. Surge and noise protector Most hV6 A surge protector is an appliance designed to protect electrical devices from power surges and voltage spikes. ... A 115 kV to 41. ... Not to be confused with lighting. ...


Semiconducting ceramics are also employed as gas sensors. When various gases are passed over a polycrystalline ceramic, its electrical resistance changes. With tuning to the possible gas mixtures, very inexpensive devices can be produced. A gas detector is a device which detects the presence of various gases within an area, usually as part of a system to warn about gases which might be harmful to humans or animals. ...


Superconductivity

Under some conditions, such as extremely low temperature, some ceramics exhibit superconductivity. The exact reason for this is not known, but there are two major families of superconducting ceramics. A magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen. ...


Ferroelectricity and supersets

Piezoelectricity, a link between electrical and mechanical response, is exhibited by a large number of ceramic materials, including the quartz used to measure time in watches and other electronics. Such devices use both properties of piezoelectrics, using electricity to produce a mechanical motion (powering the device) and then using this mechanical motion to produce electricity (generating a signal). The unit of time measured is the natural interval required for electricity to be converted into mechanical energy and back again. Piezoelectricity is the ability of some materials (notably crystals and certain ceramics) to generate an electric potential[1] in response to applied mechanical stress. ... A crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. ...


The piezoelectric effect is generally stronger in materials that also exhibit pyroelectricity, and all pyroelectric materials are also piezoelectric. These materials can be used to inter convert between thermal, mechanical, and/or electrical energy; for instance, after synthesis in a furnace, a pyroelectric crystal allowed to cool under no applied stress generally builds up a static charge of thousands of volts. Such materials are used in motion sensors, where the tiny rise in temperature from a warm body entering the room is enough to produce a measurable voltage in the crystal. Pyroelectricity is the ability of certain materials to generate an electrical potential when they are heated or cooled. ... Motion detection includes methods by which motion has be identified. ...


In turn, pyroelectricity is seen most strongly in materials which also display the ferroelectric effect, in which a stable electric dipole can be oriented or reversed by applying an electrostatic field. Pyroelectricity is also a necessary consequence of ferroelectricity. This can be used to store information in ferroelectric capacitors, elements of ferroelectric RAM. In physics, the ferroelectric effect is an electrical phenomenon whereby certain ionic crystals may exhibit a spontaneous dipole moment. ... Ferroelectric capacitor is a capacitor used in digital electronics as a component of computer memory. ... Ferroelectric RAM (FRAM or FeRAM) is a type of non-volatile computer memory, similar to EEPROM but based on electric field orientation and with near-unlimited number (exceeding 1010 for 5V devices and even more for 3. ...


The most common such materials are lead zirconate titanate and barium titanate. Aside from the uses mentioned above, their strong piezoelectric response is exploited in the design of high-frequency loudspeakers, transducers for sonar, and actuators for atomic force and scanning tunneling microscopes. Lead zirconium titanate (PZT, also Lead zirconate titanate) is a ceramic perovskite material that shows a marked piezoelectric effect - that is, it develops a voltage difference across two of its faces when compressed, and ferroelectric effect. ... Barium titanate is an oxide of barium and titanium with the chemical formula BaTiO3. ... For the Marty Friedman album, see Loudspeaker (album) An inexpensive low fidelity 3. ... This article is about underwater sound propagation. ... Topographic scan of a glass surface The atomic force microscope (AFM) is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. ... Image of reconstruction on a clean Au(100) surface. ...


Positive thermal coefficient

Increases in temperature can cause grain boundaries to suddenly become insulating in some semiconducting ceramic materials, mostly mixtures of heavy metal titanates. The critical transition temperature can be adjusted over a wide range by variations in chemistry. In such materials, current will pass through the material until joule heating brings it to the transition temperature, at which point the circuit will be broken and current flow will cease. Such ceramics are used as self-controlled heating elements in, for example, the rear-window defrost circuits of automobiles. For other uses, see Heavy metal (disambiguation). ... The chemical compound Titanic acid, Ti(OH)4, is a white weak acid that is a hydrated form of titanium dioxide. ... In electronics, and in physics more broadly, Joule heating refers to the increase in temperature of a conductor as a result of resistance to an electrical current flowing through it. ...


At the transition temperature, the material's dielectric response becomes theoretically infinite. While a lack of temperature control would rule out any practical use of the material near its critical temperature, the dielectric effect remains exceptionally strong even at much higher temperatures. Titanates with critical temperatures far below room temperature have become synonymous with "ceramic" in the context of ceramic capacitors for just this reason. A dielectric is a physical model commonly used to describe how an electric field behaves inside a material. ...


Classification of ceramics

Non-crystalline ceramics: Non-crystalline ceramics, being glasses, tend to be formed from melts. The glass is shaped when either fully molten, by casting, or when in a state of toffee-like viscosity, by methods such as blowing to a mold. If later heat-treatments cause this class to become partly crystalline, the resulting material is known as a glass-ceramic. Glass-ceramic is a mixture of glass and ceramic materials (mainly lithium-, silicon-, or aluminium-oxides) yielding a material that is impervious to even extreme temperature shocks. ...


Crystalline ceramics: Crystalline ceramic materials are not amenable to a great range of processing. Methods for dealing with them tend to fall into one of two categories - either make the ceramic in the desired shape, by reaction in situ, or by "forming" powders into the desired shape, and then sintering to form a solid body. Ceramic forming techniques include shaping by hand (sometimes including a rotation process called "throwing"), slip casting, tape casting (used for making very thin ceramic capacitors, etc.), injection molding, dry pressing, and other variations. (See also Ceramic forming techniques. Details of these processes are described in the two books listed below.) A few methods use a hybrid between the two approaches. Ceramic forming techniques are ways of forming ceramic shapes. ...


In situ manufacturing

The most common use of this method is in the production of cement and concrete. Here, the dehydrated powders are mixed with water. This starts hydration reactions, which result in long, interlocking crystals forming around the aggregates. Over time, these result in a solid ceramic.


The biggest problem with this method is that most reactions are so fast that good mixing is not possible, which tends to prevent large-scale construction. However, small-scale systems can be made by deposition techniques, where the various materials are introduced above a substrate, and react and form the ceramic on the substrate. This borrows techniques from the semiconductor industry, such as chemical vapour deposition, and is very useful for coatings. DC plasma (violet) enhances the growth of carbon nanotubes in this laboratory-scale PECVD apparatus. ...


These tend to produce very dense ceramics, but do so slowly.


Sintering-based methods

The principles of sintering-based methods is simple. Once a roughly held together object (called a "green body") is made, it is baked in a kiln, where diffusion processes cause the green body to shrink. The pores in the object close up, resulting in a denser, stronger product. The firing is done at a temperature below the melting point of the ceramic. There is virtually always some porosity left, but the real advantage of this method is that the green body can be produced in any way imaginable, and still be sintered. This makes it a very versatile route. diffusion (disambiguation). ... Porosity is a measure of the void spaces in a material, and is measured as a fraction, between 0–1, or as a percentage between 0–100%. The term porosity is used in multiple fields including manufacturing, earth sciences and construction. ...


There are thousands of possible refinements of this process. Some of the most common involve pressing the green body to give the densification a head start and reduce the sintering time needed. Sometimes organic binders such as polyvinyl alcohol are added to hold the green body together; these burn out during the firing (at 200–350°C). Sometimes organic lubricants are added during pressing to increase densification. It is not uncommon to combine these, and add binders and lubricants to a powder, then press. (The formulation of these organic chemical additives is an art in itself. This is particularly important in the manufacture of high performance ceramics such as those used by the billions for electronics, in capacitors, inductors, sensors, etc. The specialized formulations most commonly used in electronics are detailed in the book "Tape Casting," by R.E. Mistler, et al., Amer. Ceramic Soc. [Westerville, Ohio], 2000.) A comprehensive book on the subject, for mechanical as well as electronics applications, is "Organic Additives and Ceramic Processing," by D. J. Shanefield, Kluwer Publishers [Boston], 1996. A binder is a material used to bind together two or more other materials in mixtures. ... Chemical structure of polyvinyl alcohol Polyvinyl alcohol (PVOH, PVA, or PVAL) is a water-soluble synthetic polymer. ... This article is about the engineering discipline. ... An inductor is a passive electrical device employed in electrical circuits for its property of inductance. ... Not to be confused with censure, censer, or censor. ...


A slurry can be used in place of a powder, and then cast into a desired shape, dried and then sintered. Indeed, traditional pottery is done with this type of method, using a plastic mixture worked with the hands.


If a mixture of different materials is used together in a ceramic, the sintering temperature is sometimes above the melting point of one minor component - a liquid phase sintering. This results in shorter sintering times compared to solid state sintering.


Other applications of ceramics

  • Ceramics are used in the manufacture of knives. The blade of the ceramic knife will stay sharp for much longer than that of a steel knife, although it is more brittle and can be snapped by dropping it on a hard surface.
  • Ceramic balls can be used to replace steel in ball bearings. Their higher hardness means that they are much less susceptible to wear and can often more than triple lifetimes. They also deform less under load meaning they have less contact with the bearing retainer walls and can roll faster. In very high speed applications, heat from friction during rolling can cause problems for metal bearings; problems which are reduced by the use of ceramics. Ceramics are also more chemically resistant and can be used in wet environments where steel bearings would rust. The major drawback to using ceramics is a significantly higher cost. In many cases their electrically insulating properties may also be valuable in bearings.
  • In the early 1980s, Toyota researched production of an adiabatic ceramic engine which can run at a temperature of over 6000 °F (3300 °C). Ceramic engines do not require a cooling system and hence allow a major weight reduction and therefore greater fuel efficiency. Fuel efficiency of the engine is also higher at high temperature, as shown by Carnot's theorem. In a conventional metallic engine, much of the energy released from the fuel must be dissipated as waste heat in order to prevent a meltdown of the metallic parts. Despite all of these desirable properties, such engines are not in production because the manufacturing of ceramic parts in the requisite precision and durability is difficult. Imperfection in the ceramic leads to cracks, which can lead to potentially dangerous equipment failure. Such engines are possible in laboratory settings, but mass-production is unfeasible with current technology.
  • Work is being done in developing ceramic parts for gas turbine engines. Currently, even blades made of advanced metal alloys used in the engines' hot section require cooling and careful limiting of operating temperatures. Turbine engines made with ceramics could operate more efficiently, giving aircraft greater range and payload for a set amount of fuel.
  • Recently, there have been advances in ceramics which include bio-ceramics, such as dental implants and synthetic bones. Hydroxyapatite, the natural mineral component of bone, has been made synthetically from a number of biological and chemical sources and can be formed into ceramic materials. Orthopedic implants made from these materials bond readily to bone and other tissues in the body without rejection or inflammatory reactions. Because of this, they are of great interest for gene delivery and tissue engineering scaffolds. Most hydroxy apatite ceramics are very porous and lack mechanical strength and are used to coat metal orthopedic devices to aid in forming a bond to bone or as bone fillers. They are also used as fillers for orthopedic plastic screws to aid in reducing the inflammation and increase absorption of these plastic materials. Work is being done to make strong, fully dense nano crystalline hydroxapatite ceramic materials for orthopedic weight bearing devices, replacing foreign metal and plastic orthopedic materials with a synthetic natural bone mineral. Ultimately these ceramic materials may be used as bone replacements or with the incorporation of protein collagens, synthetic bones.

A ceramic knife is a knife made out of very hard ceramic, often zirconia. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... Boron carbide (chemical formula B4C) is an extremely hard ceramic material used in tank armor, bulletproof vests, and numerous industrial applications. ... This article or section does not adequately cite its references or sources. ... For other uses, see Rifle (disambiguation). ... It has been suggested that this article or section be merged into Ceramic plate. ... Cockpit of a light aircraft, showing instrumentation dials and dual control yokes. ... This article is about the automaker. ... This article covers adiabatic processes in thermodynamics. ... Fuel efficiency, in its basic sense, is the same as thermal efficiency, meaning the efficiency of a process that converts energy contained in a carrier fuel into energy or work. ... A Carnot heat engine is a hypothetical engine that operates on the reversible Carnot cycle. ... Waste heat is the by-product heat of machines and technical processes for which no useful application is found. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ... A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. ... A superalloy, or high-performance alloy, is an alloy able to withstand extreme temperatures that would destroy conventional metals like steel and aluminum. ... Hydroxylapatite is a naturally occurring form of calcium apatite with the formula Ca5(PO4)3(OH), but is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two molecules. ...

See also

Look up Ceramic in
Wiktionary, the free dictionary.

Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 150 languages. ... Ancient Egyptian ceramic art: Louvre Museum. ... Ceramic forming techniques are ways of forming ceramic shapes. ... There are very few or no other articles that link to this one. ... “Fine China” redirects here. ... Unfired green ware pottery on a traditional drying rack at Conner Prairie living history museum. ... Geopolymer is a term covering a class of synthetic aluminosilicate materials with potential use in a number of areas, but predominantly as a replacement for Portland-based cements. ... The three point bending flexural test provides values for the modulus of elasticity in bending , flexural stress , flexural strain and the flexural stress-strain response of the material. ...

External links

  • Advanced Ceramics – The Evolution, Classification, Properties, Production, Firing, Finishing and Design of Advanced Ceramics
  • How pottery is made
  • How sanitaryware is made
  • World renowned ceramics collections at Stoke-on-Trent Museum Click on Quick Links in the right-hand column to view examples.
  • The Gardiner Museum - The only museum in Canada entirely devoted to ceramics.
  • Online database of ceramic artists, companies, and organisations
  • [1]-Introduction, Scientific Principles, Properties and Processing of Ceramics

  Results from FactBites:
 
Ceramics - Victoria and Albert Museum (145 words)
It is from a very large group of animals and birds ordered from the Meissen factory for the porcelain menagerie that Augustus planned for the upper floor of the 'Japanese Palace' at Dresden.
This comprehensive addition to the VandA website contains 60 videos and transcripts about ten selected objects from the Museum's 20th century ceramics collection.
Six people from the world of ceramics talk about each of the ten pots, giving a range of fascinating insights into a number of different pieces.
INTRODUCTION TO CERAMICS at NEWI (2497 words)
Ceramics can be defined as inorganic, non-metallic materials that are typically produced using clays and other minerals from the earth or chemically processed powders.
Ceramics are typically crystalline in nature and are compounds formed between metallic and non-metallic elements such as aluminium and oxygen (alumina- Al), silicon and nitrogen (silicon nitride- Si) and silicon and carbon (silicon carbide-SiC).
Ceramic, or high-temperature superconductors are now being developed for commercial applications and appear to be a sure bet to enter more commercial markets over the next few years.
  More results at FactBites »

 
 

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