Sintering is a method for making objects from powder, by heating the material (below its melting point) until its particles adhere to each other. Sintering is traditionally used for manufacturing ceramic objects, and has also found uses in such fields as powder metallurgy. Powder is a substance that has been crushed into very fine grains. ... The melting point of a solid is the temperature at which it changes state from solid to liquid. ... Dew drops adhering to a spider web Adhesion is the molecular attraction exerted between bodies in contact. ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικος (keramikos, potters earth, or pottery). The term covers inorganic non-metallic materials whose formation is due to the action of heat. ... Powder metallurgy is a forming and fabrication technique consisting of three major processing stages. ...

The word "sinter" comes from the Middle High German Sinter, a cognate of English "cinder". This article or section does not cite its references or sources. ...

Sintered bronze in particular is frequently used as a material for bearings, since its porosity allows lubricants to flow through it. In the case of materials with high melting points such as Teflon and tungsten, sintering is used when there is no alternative manufacturing technique. In these cases very low porosity is desirable and can often be achieved. Assorted ancient Bronze castings found as part of a cache, probably intended for recycling. ... A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... Teflon is polytetrafluoroethylene (PTFE), a polymer of fluorinated ethylene. ... General Name, Symbol, Number tungsten, W, 74 Chemical series transition metals Group, Period, Block 6, 6, d Appearance grayish white, lustrous Atomic mass 183. ...

In most cases the density of a collection of grains increases as material flows into voids, causing a decrease in overall volume. Mass movements that occur during sintering consist of the reduction of total porosity by repacking, followed by material transport due to evaporation and condensation from diffusion. In the final stages, metal atoms move along crystal boundaries to the walls of internal pores, redistributing mass from the internal bulk of the object and smoothing pore walls. Surface tension is the driving force for this movement. This article or section is in need of attention from an expert on the subject. ... Water vapor condensing over a cup of hot tea Condensation is the change in matter of a substance to a denser phase, such as a gas (or vapor) to a liquid. ... This article or section does not cite its references or sources. ... A pore, in general, is some form of opening, usually very small. ... In physics, surface tension is an effect within the surface layer of a liquid that causes that layer to behave as an elastic sheet. ...

Metallurgists can sinter most, if not all, metals. This applies especially to pure metals produced in vacuum which suffer no surface contamination. Many nonmetallic substances also sinter, such as glass, alumina, zirconia, silica, magnesia, lime, beryllium oxide, ferric oxide, and various organic polymers. Sintering, with subsequent reworking, can produce a great range of material properties. Changes in density, alloying, or heat treatments can alter the physical characteristics of various products. For instance, the tensile strength E_n of sintered iron powders remains insensitive to sintering time, alloying, or particle size in the original powder, but depends upon the density (D) of the final product according to E_n/E = (D/d)^3.4, where E is Young's modulus and d is the maximum density of iron. Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... Zirconia (ZrO2) is a white crystalline oxide of zirconium. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Periclase occurs naturally in contact metamorphic rocks and is a major component of most basic refractory bricks. ... Lime is a general term for various naturally occurring minerals and materials derived from them in which carbonates, oxides and hydroxides of calcium predominate. ... Beryllium oxide (BeO) is a white crystalline oxide. ... Iron(III) oxide - also known as ferric oxide, red iron oxide, synthetic maghemite, rouge,or rust - is one of several oxide compounds of iron, and is most notable for its ferromagnetic properties. ... Benzene An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with the exception of carbides, carbonates, carbon oxides and elementary carbon. ... Polymer is a term used to describe large molecules consisting of repeating structural units, or monomers, connected by covalent chemical bonds. ... An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... It has been suggested that this article or section be merged into Strength of materials. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... This article is about a physical property. ...

Particular advantages of this powder technology include:

1. the possibility of very high purity for the starting materials and their great uniformity
2. preservation of purity due to the restricted nature of subsequent fabrication steps
3. stabilization of the details of repetitive operations by control of grain size in the input stages
4. absence of stringering of segregated particles and inclusions (as often occurs in melt processes)
5. no requirement for deformation to produce directional elongation of grains

Many literary references exist on sintering dissimilar materials for solid/solid phase compounds or solid/melt mixtures in the processing stage. Any substance which melts may also become atomized using a variety of powder production techniques. When working with pure elements, one can recycle scrap remaining at the end of parts manufacturing through the powdering process for reuse. ... Fabrication may refer to more than one thing: Fabrication (metal) Semiconductor device fabrication Lie Fiction Fable This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Stringering in swordsmanship is the clasping of opposing blade surfaces pressed together, used as a protective move to prevent thrusts. ... In engineering mechanics, deformation is a change in shape due to an applied force. ...

Ceramic sintering

Ancient sintering techniques for the making of pottery and ceramic art objects remain in wide use to this day, but research has also led to more advanced techniques which work for a wider array of ceramics. Most ceramic materials have a lower affinity for water and a lower plasticity index than clay, requiring organic additives in the stages before sintering. The general procedure of creating ceramic objects via sintering of powders includes: Unfired green ware pottery on a traditional drying rack at Conner Prairie living history museum. ... Look up affinity in Wiktionary, the free dictionary. ... The Plasticity Index (often abbreviated as PI) is a numerical measure of the plasticity of a soil. ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ...

• Mixing water, binder, anti-flocculant, and ceramic powder to form a slurry
• Spray-drying the slurry
• Putting the spray dried powder into a mold and pressing it to form a green body (an unsintered ceramic item)
• Heating the green body at low temperature to burn off the binder
• Sintering at a high temperature to fuse the ceramic particles together

There are two types of sintering: with pressure (also known as hot pressing), and without pressure. A variant used for 3D shapes is called hot isostatic pressing. A deflocculant is a thinning agent used to reduce viscosity or prevent flocculation; incorrectly called a dispersant. ... A slurry is a mixture, which comes in different varieties: Metal Slurry can be used in pipe fitting and other welding tasks, as well as slurry based bombs like the BLU-82. ... Spray drying is the process of mixing and drying a slurry (a kind of suspension) to form a homogeneous mixture of powders. ... One half of a bronze mould for casting a socketed spear head dated to the period 1400-1000 BC. There are no known parallels for this mould. ...

See also

• Selective laser sintering, a rapid prototyping technology.