you ever wondered what are the enigmatic amorphous materials?According to the structure, and they are different from solid and liquid from.The fact that such bodies are condensed in a special state, having only short-range order.Examples of amorphous materials - resin, glass, amber, rubber, polyethylene, polyvinyl chloride (PVC windows our favorite), and various other polymers.This solid bodies which do not have a crystal lattice.Yet they include wax, various adhesives, hard rubber and plastic.
Unusual properties of amorphous substances
During splitting in amorphous bodies are not formed faces.The particles completely randomly and are in close proximity to each other.They may be highly dense and viscous.How they are affected by external factors?Under the influence of different temperatures of the body are flowing like a liquid, and at the same time quite elastic.In the case where the external action does not last long, the amorphous structure of the material may crack when a powerful blow to pieces.Long-term impact from the outside leads to the fact that they simply flow.
Try to spend a little experiment at home with the use of resin.Put it on a hard surface, and you'll notice that it begins to flow smoothly.That's right, because it is amorphous!The rate depends on the temperature readings.If it will be very high, the resin begins to flow much faster.
What else is characteristic of such bodies?They can take any form.If the amorphous material in the form of small particles into a vessel, such as a pitcher, they also take the form of the vessel.Yet they are isotropic, ie they exhibit the same physical properties in all directions.
melting and transition to other states.Metal and glass
amorphous state of matter is not intended to maintain a certain temperature.At low rates of body stiffen, high - melt.Incidentally, this also depends on the viscosity of the substances.The low temperature helps to reduce the viscosity is high, on the contrary, it increases.
For substances amorphous type can be distinguished one more feature - the transition to the crystalline state, and spontaneous.Why is this happening?The internal energy in the crystalline body is much smaller than in the amorphous.We can observe this in the example of glass production - with time windows become cloudy.
metallic glass - what is it?Metal can eliminate the crystal lattice during the melting, that is to make the material amorphous glassy structure.During hardening the artificial cooling of the crystal lattice is formed again.Amorphous metal has a remarkable resilience to corrosion.For example, to make him a body of the car would not need a variety of coatings, as not subjected to accidental break-ups.Amorphous material is a body, whose atomic structure has unprecedented strength, and thus amorphous metal could be used in a completely any industrial sector.
crystal structure of substances
to a good understanding of the characteristics of metals and to be able to work with them, you need to have knowledge of the crystal structure of various substances.Metal manufacturing industry and the region have not been able to get such a development, if people did not have certain knowledge about the changes in the structure of alloys, technological methods and performance.
four states of matter
is well known that there are four aggregate states: solid, liquid, gaseous, plasma.Amorphous solid can be crystalline.With such a structure can be observed spatial periodicity in the arrangement of the particles.These particles in crystals can perform periodic motion.All the bodies that we see in the gaseous or liquid state, you can see the movement of particles in a chaotic mess.Amorphous solids (eg metals in the condensed state: ebony, glass products, resin) can be called frozen liquid type, because they have a change can be seen form the characteristic trait of the viscosity.
difference amorphous solids from gases and liquids
Manifestations of plasticity, elasticity, strain hardening characteristic of many bodies.The crystalline and amorphous substances are more possess these characteristics, while the liquids and gases do not have such properties.But you can see that they contribute to the elastic volume change.
crystalline and amorphous materials.Mechanical and physical properties
What are the crystalline and amorphous materials?As mentioned above, it may be called amorphous those bodies which have enormous viscosity, at ordinary temperature and their fluidity is impossible.But high temperatures, in contrast, allows it to be flowable as a fluid.
Very different from the substance of the crystalline type.These solids can have its melting point, depending on the external pressure.Preparation of crystals possibly cooling the liquid.If you do not take certain measures, we can see that in the liquid state are beginning to have different centers of crystallization.The region surrounding these centers, the formation of a solid.Very small crystals begin to connect with each other in a chaotic manner, and it turns out the so-called polycrystalline.Such a body is isotropic.
Features substances
What determines the physical and mechanical properties of the bodies?Are important atomic bonds, as well as the type of crystal structure.Crystals ionic type characterized by ionic bonds, which means that the smooth transition from one atom to another.Thus the formation of positively and negatively charged particles.Ionic bond, we can observe a simple example - are characteristics peculiar to a variety of oxides and salts.Another feature of ionic crystals - low heat conductivity, but its performance can increase considerably when heated.The lattice sites can be seen a variety of molecules that differ strong atomic bonds.
set of minerals that we find everywhere in nature, have a crystalline structure.And amorphous state of matter - it is also the nature in its purest form.Only in this case the body is something formless, but the crystals can take the form of beautiful polyhedra with having flat faces, as well as form new amazing beauty and purity of the solids.
What are crystals?Amorphous-crystalline structure
form such bodies is constant for a given connection.For example, Beryl always looks like a hexagonal prism.Spend a little experiment.Take a small crystal of salt cubic shape (the ball) and put it in a special solution as much as possible the same saturated salt.Over time, you'll notice that the body remains the same - it again took the form of a cube or a sphere, which is inherent in the crystals of salt.
semicrystalline material - these bodies, which may contain both amorphous and crystalline phases.What affects the material properties of such a structure?Mainly a different ratio of the volume and different location in relation to each other.Common examples of such materials are materials made of ceramic, porcelain, glass ceramics.From the table of properties of materials with amorphous-crystalline structure it becomes aware that porcelain contains the maximum percentage of the glass phase.Performance varies between 40-60-year-percent.The lowest content we see on the example of stone casting - less than 5 percent.At this higher absorption of water will have ceramic tile.
As you know, industrial materials such as porcelain, ceramic tile, stone molding and glass ceramics - is amorphous-crystalline materials, because they contain glassy phase while the crystals in its structure.It should be noted that material properties do not depend on the content of the glass phase.
Amorphous metals
Application amorphous substances most actively carried out in the field of medicine.For example, quick cooling of the metal is widely used in surgery.Due to the related developments, many people were able to move independently after a serious injury.The fact is that the substance of the amorphous structure is an excellent biomaterial for implantation into bone.These special screws, plates, pins, safety pins implement in severe fractures.Previously, in surgery for such purposes used steel and titanium.Only later it was noticed that amorphous materials decompose very slowly in the body and is an amazing feature makes it possible to recover the bone tissue.Subsequently, the substance is replaced by bone.
application of amorphous materials such as in metrology and precision mechanics
Precision mechanics is based on the accuracy of, and therefore is called.A particularly important role in the industry, as well as in the metrology instrument play figures ultra precise measurement, it allows for use in devices amorphous solids.Through precise measurements conducted laboratory and research institutes in the field of mechanics and physics, there is a reception of new products, improvement of scientific knowledge.
Polymers
Another example of application of amorphous material - a polymer.They may slowly change from solid to liquid, while the crystalline polymers have a melting point rather than a softening temperature.What is the physical state of amorphous polymers?If you give these substances a low temperature, you will notice that they will be in the glassy state and exhibit the properties of solids.Gradual warming contributes to the fact that the polymers are beginning to move into a state of increased elasticity.
amorphous substance, examples of which we are led, are used extensively in industry.Superelastic state allows polymers somehow deformed, and this state is achieved due to the increased flexibility of the links and molecules.Further increase in temperature leads to a performance that the polymer becomes even more elastic properties.He begins to go into a special fluid and viscous state.
If you leave the situation without control and prevent further increase in temperature, the polymer is subjected to destruction, that is destruction.Viscous state indicates that all the links in the macromolecule are very mobile.When flowing polymer molecule, the links not only straightened, but also much closer to each other.Intermolecular effect turns into a solid polymer material (rubber).This process is called vitrification mechanically.The resulting material was used for the production of films and fibers.
Polymer basis available polyamides, polyacrylonitriles.To manufacture the polymer film, it is necessary to push the polymer through the spinneret which have slot-like opening, and applied to the tape.Thus manufactured packaging materials and bases for magnetic tapes.Polymers also include various varnishes (forming the foam in an organic solvent), adhesives, and other fastening materials and composites (base resin with a filler), plastics.
Applications polymers
This kind of amorphous substance strongly infiltrated into our lives.They are used everywhere.These include:
1. Various foundations for the manufacture of varnishes, adhesives, plastic products (phenol-formaldehyde resins).
2. elastomers or synthetic rubbers.
3. Insulating material - PVC, or the famous plastic PVC windows.It is resistant to fire, as it is considered nonflammable, has a high mechanical strength and electrical insulation properties.
4. Polyamide - a substance having a very high strength, wear resistance.He is characterized by high dielectric characteristics.
5. Plexiglass or polymethyl methacrylate.Him we can use in the field of electrical engineering, or to use as a material for construction.
6. Teflon, or polytetrafluoroethylene, - known insulator, which does not exhibit the properties of dissolution in organic solvents.Extensive temperature range and good dielectric properties allow to use it as a hydrophobic or anti-friction material.
7. Polystyrene.This material is not exposed to acid.It, as well as Teflon, and polyamide can be considered as a dielectric.Very durable against mechanical impact.Polystyrene is used everywhere.For example, it is well established as a structural and insulating material.It is used in electricity and electronics.
8. Probably the best known polymer for us - it is polyethylene.The material is resistant when exposed to aggressive environment, it is absolutely not transmit moisture.If the package is made of polyethylene, can not be afraid that the contents will deteriorate under the influence of heavy rain.Polyethylene - is also a dielectric.Its use is extensive.Because it is manufactured pipe design, a variety of electrical products, insulation film, membrane cable telephone and power lines, parts for radios and other equipment.
9. PVC - a high-polymer material.It is a synthetic and thermoplastic.It has the structure of molecules which are asymmetric.Almost is water and is made by molding by stamping or by molding.PVC is used most often in the electrical industry.On the basis of creating a variety of insulating tubes and hoses for chemical protection, battery banks, grommets and gaskets, wire and cable.PVC is also an excellent substitute for harmful lead.It can not be used as high-frequency circuits as dielectric.And all of the fact that in this case the level of dielectric losses will be high.It has high conductivity.
