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Encyclopedia > Amorphous solid
Wax and paraffin are amorphous.

An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. (Solids in which there is long-range atomic order are called crystalline solids or morphous). Most classes of solid materials can be found or prepared in an amorphous form. For instance, common window glass is an amorphous ceramic, many polymers (such as polystyrene) are amorphous, and even foods such as cotton candy are amorphous solids. Image File history File linksMetadata Download high-resolution version (1664x2240, 735 KB) Just a shot above of yellow-orange candle with burnt wick, on white background Source: http://sxc. ... Image File history File linksMetadata Download high-resolution version (1664x2240, 735 KB) Just a shot above of yellow-orange candle with burnt wick, on white background Source: http://sxc. ... candle wax This page is about the substance. ... Paraffin is a common name for a group of alkane hydrocarbons with the general formula CnH2n+2, where n is greater than about 20, discovered by Carl Reichenbach. ... For other uses, see Solid (disambiguation). ... In physics, long-range order characterizes physical systems in which remote portions of the same sample exhibit correlated behavior. ... Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ... Quartz crystal Synthetic bismuth hopper crystal Insulin crystals Gallium, a metal that easily forms large single crystals A huge monocrystal of potassium dihydrogen phosphate grown from solution by Saint-Gobain for the megajoule laser of CEA. In chemistry and mineralogy, a crystal is a solid in which the constituent atoms... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... A polymer is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... Polystyrene is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... Cotton candy (American English), candy floss (British English), or fairy floss (Australian English) is a form of spun sugar. ...


Amorphous materials are often prepared by rapidly cooling molten material, such as glass. The cooling reduces the mobility of the material's molecules before they can pack into a more thermodynamically favorable crystalline state. Amorphous materials can also be produced by additives which interfere with the ability of the primary constituent to crystallize. For example addition of soda to silicon dioxide results in window glass and the addition of glycols to water results in a vitrified solid. Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dunamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... Sodium carbonate (also known as washing soda or soda ash), Na2CO3, is a sodium salt of carbonic acid. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... A diol is a chemical compound containing two hydroxyl groups (-OH groups). ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... A vitrification experiment for the study of nuclear waste disposal at Pacific Northwest National Labs Vitrification is a process of converting a material into a glass-like amorphous solid which is free of any crystalline structure, either by the quick removal or addition of heat, or by mixing with an...


Some materials, such as metals, are difficult to prepare in an amorphous state. Unless a material has a high melting temperature (as ceramics do) or a low crystallization energy (as polymers tend to), cooling must be done extremely rapidly. As the cooling is performed, the material changes from a supercooled liquid, with properties one would expect from a liquid state material, to a solid. The temperature at which this transition occurs is called the glass transition temperature or Tg. A liquid will usually assume the shape of its container A liquid is one of the main states of matter. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... A material’s glass transition temperature, Tg, is the temperature below which molecules have little relative mobility. ...

Contents

Glasses

In common parlance, the term glass refers to amorphous oxides, and especially silicates (compounds based on silicon and oxygen). Ordinary soda-lime glass, used in windows and drinking containers, is created by the addition of soda and lime (calcium oxide) to silicon dioxide. Without these additives silicon dioxide will (with slow cooling) form quartz crystals, not glass. 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. ... 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. ... Sodium carbonate (also known as washing soda or soda ash), Na2CO3, is a sodium salt of carbonic acid. ... Calcium oxide (CaO), commonly known as lime, quicklime or burnt lime, is a widely used chemical compound. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... Quartz is one of the most common minerals in the Earths continental crust. ... 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. ...


To avoid confusion, other types of glass often are referred to with a modifier, such as the term metallic glass to refer to amorphous metallic alloys. An amorphous metal is a metallic material with a disordered atomic-scale structure. ...

Unsolved problems in physics: What is the nature of the transition between a fluid or regular solid and a glassy phase? What are the physical processes giving rise to the general properties of glasses?

Image File history File links No higher resolution available. ... This is a list of some of the unsolved problems in physics. ... In physics, a phase transition, (or phase change) is the transformation of a thermodynamic system from one phase to another. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ...

Metallic glass

Some amorphous metallic alloys can be prepared under special processing conditions (such as rapid solidification, thin-film deposition, or ion implantation), but the term "metallic glass" refers only to rapidly solidified materials. Thin-film deposition is any technique for depositing a thin film of material onto a substrate or onto previously deposited layers. ... Ion implantation is a materials engineering process by which ions of a material can be implanted into another solid, thereby changing the physical properties of the solid. ...


Even with special equipment, such rapid cooling is required that, for most metals, only a thin wire or ribbon can be made amorphous. This is enough for many magnetic applications, but thicker sections are required for most structural applications such as scalpel blades, golf clubs, and cases for consumer electronics. Recent efforts have made it possible to increase the maximum thickness of glassy castings, by finding alloys where kinetic barriers to crystallization are greater. Such alloy systems tend to have the following inter-related properties: In physics, magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials. ... A scalpel is a very sharp knife used for surgery, anatomical dissection, and various arts and crafts. ... Golf club can mean several things: For the piece of sports equipment, see golf club (equipment) For an organization (whether non-profit or for profit) enrolling members and maintaining a golf course for their use, see country club. ... Consumer electronics is a term used to describe the category of electronic equipment intended for everyday use by people, the consumers. ... Casting may be used to create artistic sculptures Casting is a manufacturing process by which a molten material such as metal or plastic is introduced into a mold, allowed to solidify within the mold, and then ejected or broken out to make a fabricated part. ... Kinetic energy (also called vis viva, or living force) is energy possessed by a body by virtue of its motion. ...

  • Many different solid phases are present in the equilibrium solid, so that any potential crystal will find that most of the nearby atoms are of the wrong type to join in crystallization
  • The composition is near a deep eutectic, so that low melting temperatures can be achieved without sacrificing the slow diffusion and high liquid viscosity seen in alloys with high-melting pure components
  • Atoms with a wide variety of sizes are present, so that "wrong-sized" atoms interfere with the crystallization process by binding to atom clusters as they form.

One such alloy is the commercial "Liquidmetal", which can be cast in amorphous sections up to an inch thick. In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... A eutectic or eutectic mixture is a mixture of two or more elements which has a lower melting point than any of its constituents. ... Liquidmetal and Vitreloy are commercial names of an amorphous alloy developed by Liquidmetal Technologies. ...


Other synthesis routes

Amorphous solids produced by other routes, such as ion implantation and thin-film deposition are, technically speaking, not glasses. Ion implantation is a materials engineering process by which ions of a material can be implanted into another solid, thereby changing the physical properties of the solid. ... Thin-film deposition is any technique for depositing a thin film of material onto a substrate or onto previously deposited layers. ...


Damage

One way to produce a material without an ordered structure is to take a crystalline material and remove the order by damaging it. A practical, controllable way to do this is by firing ions into the material at high speed, so that collisions inside the material knock all atoms from their original positions. This technique is known as ion implantation, and only forms amorphous solids if the material is too cold for atoms to diffuse back to their original positions as the process continues. ... Ion implantation is a materials engineering process by which ions of a material can be implanted into another solid, thereby changing the physical properties of the solid. ...


Cold deposition

Techniques such as sputter deposition and chemical vapour deposition can be used to deposit a thin film of material onto a surface. If the surface is kept cold, the atoms being deposited will not, on average, gain enough energy to diffuse along the surface until they find a place in an ordered crystal. For every deposition technique, there is a substrate temperature below which the deposited film will be amorphous. However, surface diffusion requires much less energy than diffusion through the bulk, so that these temperatures are often lower than those required to make amorphous films by ion implantation. Sputter deposition is a method of depositing thin films by sputtering a block of source material onto a substrate. Sputtered atoms ejected into the gas phase are not in their thermodynamic equilibrium state, and tend to deposit on all surfaces in the vacuum chamber. ... DC plasma (violet) enhances the growth of carbon nanotubes in this laboratory-scale PECVD apparatus. ... This article or section does not cite any references or sources. ...


Toward a strict definition

It is difficult to make a distinction between truly amorphous solids and crystalline solids in which the size of the crystals is very small (less than two nanometres). Even amorphous materials have some short-range order among the atomic positions (over length scales of less than five nanometres). Furthermore, in very small crystals a large fraction of the atoms are located at or near the surface of the crystal; relaxation of the surface and interfacial effects distort the atomic positions, decreasing the structural order. Even the most advanced structural characterization techniques, such as x-ray diffraction and transmission electron microscopy, have difficulty in distinguishing between amorphous and crystalline structures on these length scales. A nanometre (American spelling: nanometer, symbol nm) is a unit of length in the metric system, equal to one thousand-millionth of a metre, which is the current SI base unit of length. ... A nanometre (American spelling: nanometer, symbol nm) is a unit of length in the metric system, equal to one thousand-millionth of a metre, which is the current SI base unit of length. ... CRYSTAL is a quantum chemistry ab initio program, designed primarily for calculations on crystals (3 dimensions), slabs (2 dimensions) and polymers (1 dimension) using translational symmetry, but it can be used for single molecules. ... Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ...


The transition from the liquid state to the glass, at a temperature below the equilibrium melting point of the material, is called the glass transition. From a practical point of view, the glass transition temperature is defined empirically as the temperature at which the viscosity of the liquid exceeds a certain value (commonly 1013 pascal-seconds). The transition temperature depends on cooling rate, with the glass transition occurring at higher temperatures for faster cooling rates. The precise nature of the glass transition is the subject of ongoing research. While it is clear that the glass transition is not a first-order thermodynamic transition (such as melting), there is debate as to whether it is a higher-order transition, or merely a kinetic effect. A simplistic view of a materials glass transition temperature (Tg) is the temperature below which molecules have very little mobility. ... Viscosity is a measure of the resistance of a fluid to deform under shear stress. ... The pascal second (symbol Pa·s) is the SI unit of dynamic viscosity. ...


Glass is sometimes referred to as a supercooled liquid; this amounts to an assertion that the glass transition is purely a kinetic, rather than a thermodynamic effect. One argument against speaking this way is the fact that supercooled liquids flow whereas glass does not. In standard usage, the term supercooled means that the fluid is still a liquid but is at a temperature below its freezing point. For example, freezing rain falls in liquid form and freezes on contact because it is already below the freezing point. See pitch drop experiment and a related section in glass. Supercooling is the process of chilling a liquid below its freezing point, without it becoming solid. ... Supercooling is the process of chilling a liquid below its freezing point, without it becoming solid. ... Freezing rain begins as snow, falling from a cloud towards earth and melts completely on its way down through a layer of relatively warm (above freezing) air. ... The pitch drop experiment at the University of Queensland. ... 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. ...


Some examples of amorphous solids are glass, polystyrene, and the silicon in many thin film solar cells. 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. ... Polystyrene is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... It has been suggested that Silicons ranking be merged into this article or section. ... Thin-film deposition is any technique for depositing a thin film of material onto a substrate or onto previously deposited layers. ... A solar cell, made from a monocrystalline silicon wafer A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. ...


See also

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. ... Amorphous silicon (a-Si) is the non-crystalline allotropic form of silicon. ... An amorphous metal is a metallic material with a disordered atomic-scale structure. ... Supercooling is the process of chilling a liquid below its freezing point, without it becoming solid. ... A vitrification experiment for the study of nuclear waste disposal at Pacific Northwest National Labs Vitrification is a process of converting a material into a glass-like amorphous solid which is free of any crystalline structure, either by the quick removal or addition of heat, or by mixing with an...

External links

  • Vogel-Tammann-Fulcher Equation Parameters
  • Fragility thy name is glass

Template:States of matter


  Results from FactBites:
 
Amorphous solid (277 words)
An amorphous solid is a solid in which the atoms do not have an ordered atomic structure.
Solids which are not amorphous are called crystalline solids.
Amorphous solids which are not oxides can also be called glass, but are often referred to with special terminology, for example amorphous metals could be called 'metallic glasses'.
Amorphous solid - definition of Amorphous solid in Encyclopedia (455 words)
An amorphous solid is a solid in which there is no long-range order of the positions of the atoms.
Amorphous solids produced by other routes, such as ion implantation are, technically speaking, not glasses.
It is difficult to make a distinction between truly amorphous solids and crystalline solids in which the size of the crystals is very small (less than two nanometers).
  More results at FactBites »

 
 

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