Glass-coating is a process invented in 1924 by G. F. Taylor and converted into production machine by Ulitovski for producing fine glass-coated metal filaments only a few micrometres in diameter.
In this process, known as the "Taylor-wire" or "microwire process" or "Taylor-Ulitovski process", the metal to be produced in microwire form is held in a glass tube, typically a borosilicate composition, which is closed at one end. This end of the tube is then heated in order to soften the glass to a temperature at which the metal part is in liquid state and the glass can be drawn down to produce a fine glass capillary containing a metal core. In recent years the process was converted to continuous one by continuously feeding the metal drop with new material. Although this process is simple enough it requires a lot of factors to be met at the same time. The continuous flow of metal that is being coated by the glass has to be melted at the same temperature as the glass otherwise there may be consistency problems which could lead to a change in the properties of the wire. This means that metals that have a high melting temperature can not be used because it may prove difficult to match the high melting point of the metal to a high melting point in a glass. The rate at which the metal wire is pulled also has to be monitored due to the fact that a fluctuation in the speed of pulling may cause a difference of width in the wire. Not only does the wire need to be pulled at the same rate but it also needs to be cooled in a stable environment, which is normally conducted by moving the wire through a stream of cooled water or oil. However. there are some apparatuses that can bypass some of these problems by heating the glass and the metal in separate chambers which allows for the use of metals with high melting points. Around the 1950s the Taylor-Ulitovski process was changed to a continuous feeding process of the materials in order to make these wires on a mass production scale.
Metal cores in the range 1 to 120 micrometres with a glass coating a few micrometres in diameter can be readily produced by this method. Glass-coated microwires successfully produced by this method include copper, silver, gold, iron, platinum, and various alloy compositions. It has even proved possible to produce amorphous metal ("glassy metal") cores because the cooling rate achievable by this process can be of the order of 1,000,000 kelvins per second. Glass-coated wire receives all of its material properties from its microstructure. The microstructure in turn receives its properties from the rate at which the wire is cooled. The magnetic properties of glass-coated wires also differ greatly from the properties of amorphous wires and cold-drawn wires due to the difference of the internal stresses that are occurring in the wire. When choosing a metal for the wire Fe-rich compositions of metals typically hold an advantage over Co-rich compositions since Co is more expensive and Fe-rich metals have better magnetic properties. The magnetic properties such as the magnetic softness of Fe-rich materials can be improved by annealing the metal while it is under mechanical stresses.When a magnet is said to be "soft" it implies that the magnetic abilities are only temporary. These magnets are easily magnetized when they are exposed to an electrical current. These types of magnets are often used in computers and technology to control the flow of electric current. This is what makes these wires useful in technological applications because they can easily control the flow of electricity in a device. A hard magnet on the other hand does not need an electrical current to remain magnetized so these magnets are permanent. These magnets are used to create magnetic fields in devices such as an automotive alternator.
The glass coating of wires improves the thermal stability of the wire. The wires will remain stable until the glass, in this case Pyrex (borosilicate), begins to soften. Pyrex generally begins to soften around 673 Kelvin, therefore, these wires can be used in coolers or in heaters that operate under the temperature of 673 Kelvin. Not only does the glass coating of the wire provide thermal stability but it also helps to prevent metallic corrosion of the wire.
Applications for microwire include miniature electrical components based on copper-cored microwire. Amorphous metal cores with special magnetic properties can even be employed in such articles as security tags and related devices. Cobalt and iron base alloys are used to produce anti-shoplifting labels and security papers. The glass-coated wire has also proven quite valuable in devices that are used to sense brain tumors and used in medical equipment. The main consumers of glass-coated wire are the medical and automobile industries since glass coated wire is very valuable when it comes to precise sensors.
The Taylor-Ulitovski process has been proven successful in academic environments however it was never duplicated for high volume mass production. The modified Adar-Bolotinsky process has made it possible to produce micro bonding wire directly from the melt, by casting instead of the traditional drawing, converting this process to a mass production scale. This special manufacturing process also makes it possible to develop RED micro wire, for example RED Copper wire which is unique composite wire with a thin glass-coating and a soft copper core. Glass-coated wire had a huge impact on the LED industry by reducing the cost of interconnect components, specifically using Copper wire instead of Gold. Using the Adar-Bolotinsky process has made it possible to coat these wires with glass which protects it from oxidisation, increasing the shelf and operating life. these improvements have contributed to the current success of LED lighting.
A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.
Solder is a fusible metal alloy used to create a permanent bond between metal workpieces. The word solder comes from the Middle English word soudur, via Old French solduree and soulder, from the Latin solidare, meaning "to make solid". In fact, solder must first be melted in order to adhere to and connect the pieces together after cooling, which requires that an alloy suitable for use as solder have a lower melting point than the pieces being joined. The solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Solder used in making electrical connections also needs to have favorable electrical characteristics.
An amorphous metal is a solid metallic material, usually an alloy, with disordered atomic-scale structure. Most metals are crystalline in their solid state, which means they have a highly ordered arrangement of atoms. Amorphous metals are non-crystalline, and have a glass-like structure. But unlike common glasses, such as window glass, which are typically electrical insulators, amorphous metals have good electrical conductivity.
A neodymium magnet (also known as NdFeB, NIB or Neo magnet) is the most widely used type of rare-earth magnet. It is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure. Developed independently in 1984 by General Motors and Sumitomo Special Metals, neodymium magnets are the strongest type of permanent magnet available commercially. Because of different manufacturing processes, they are divided into two subcategories, namely sintered NdFeB magnets and bonded NdFeB magnets. They have replaced other types of magnets in many applications in modern products that require strong permanent magnets, such as electric motors in cordless tools, hard disk drives and magnetic fasteners.
Nichrome is any of various alloys of nickel, chromium, and often iron. The most common usage is as resistance wire, as heating elements in things like toasters and space heaters, although they are also used in some dental restorations (fillings) and in a few other applications.
Cunife is an alloy of copper (Cu), nickel (Ni), iron (Fe), and in some cases cobalt (Co). The alloy has the same linear coefficient of expansion as certain types of glass, and thus makes an ideal material for the lead out wires in light bulbs and thermionic valves. Fernico exhibits a similar property. It is a magnetic alloy and can be used for making magnets.
Plating is a surface covering in which a metal is deposited on a conductive surface. Plating has been done for hundreds of years; it is also critical for modern technology. Plating is used to decorate objects, for corrosion inhibition, to improve solderability, to harden, to improve wearability, to reduce friction, to improve paint adhesion, to alter conductivity, to improve IR reflectivity, for radiation shielding, and for other purposes. Jewelry typically uses plating to give a silver or gold finish.
An intermetallic is a type of metallic alloy that forms a solid-state compound exhibiting defined stoichiometry and ordered crystal structure.
A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. Unlike the Peltier effect, this process is independent of the direction of current.
A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying the coating may be decorative, functional, or both. The coating itself may be an all-over coating, completely covering the substrate, or it may only cover parts of the substrate. An example of all of these types of coating is a product label on many drinks bottles- one side has an all-over functional coating and the other side has one or more decorative coatings in an appropriate pattern to form the words and images.
A superalloy, or high-performance alloy, is an alloy with the ability to operate at a high fraction of its melting point. Several key characteristics of a superalloy are excellent mechanical strength, resistance to thermal creep deformation, good surface stability, and resistance to corrosion or oxidation.
A ferrite is a ceramic material made by mixing and firing large proportions of iron(III) oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as barium, manganese, nickel, and zinc. They are electrically nonconductive, meaning that they are insulators, and ferrimagnetic, meaning they can easily be magnetized or attracted to a magnet. Ferrites can be divided into two families based on their resistance to being demagnetized (magnetic coercivity).
Electrical steel is an iron alloy tailored to produce specific magnetic properties: small hysteresis area resulting in low power loss per cycle, low core loss, and high permeability.
Resistance wire is wire intended for making electrical resistors. It is better if the alloy used has a high resistivity, since a shorter wire can then be used. In many situations, the stability of the resistor is of primary importance, and thus the alloy's temperature coefficient of resistivity and corrosion resistance play a large part in material selection.
Wolfson Centre for Magnetics (WCM) is a research and knowledge centre operating within School of Engineering at Cardiff University.
Glass-to-metal seals are a very important element of the construction of vacuum tubes, electric discharge tubes, incandescent light bulbs, glass encapsulated semiconductor diodes, reed switches, pressure tight glass windows in metal cases, and metal or ceramic packages of electronic components.
Superconducting wires are wires made of superconductors. When cooled below their transition temperatures, they have zero electrical resistance. Most commonly, conventional superconductors such as niobium-titanium are used, but high-temperature superconductors such as YBCO are entering the market. Superconducting wire's advantages over copper or aluminum include higher maximum current densities and zero power dissipation. Its disadvantages include the cost of refrigeration of the wires to superconducting temperatures, the danger of the wire quenching, the inferior mechanical properties of some superconductors, and the cost of wire materials and construction. Its main application is in superconducting magnets, which are used in scientific and medical equipment where high magnetic fields are necessary.
Splat quenching is a metallurgical, metal morphing, technique used for forming metals with a particular crystal structure by means of extremely rapid quenching, or cooling.
Chromium(III) boride, also known as chromium monoboride (CrB), is an inorganic compound with the chemical formula CrB. It is one of the six stable binary borides of chromium, which also include Cr2B,Cr5B3, Cr3B4, CrB2, and CrB4. Like many other transition metal borides, it is extremely hard (21-23 GPa), has high strength (690 MPa bending strength), conducts heat and electricity as well as many metallic alloys, and has a high melting point (~2100 oC). Unlike pure chromium, CrB is known to be a paramagnetic, with a magnetic susceptibility that is only weakly dependent on temperature. Due to these properties, among others, CrB has been considered as a candidate material for wear resistant coatings and high-temperature diffusion barriers.
Dr. Arcady P. Zhukov graduated in 1980 from the Moscow Steel and Alloys Institute, received Ph.D. degree from the Institute of Solid State Physics (Chernogolovka) of the Russian Academy of Science in 1988 and Doctor of Science (habilitation) from Moscow State “Lomonosov” University – in 2010. Presently -Ikerbasque Research professor at the Department of the Materials Physics of the University of Basque Country, Spain. He has published more than 450 referred papers in the international journals. A. Zhukov chaired Donostia International Workshop on Energy, Materials, and Nanotechnology (DINEMN),, International workshop on magnetic wires (IWMW-7) en Ordizia, co-chaired Donostia International Conference on Nanoscaled Magnetism (DICNMA), III Joint European Magnetic Symposia, organized and chaired few session of most important international conferences, gave above 50 invited talks at few international conferences. He is an associate Editor of IEEE Magnetic letters and International Journal on Smart Sensing and Intelligent Systems, member of several editorial boards and various committees of International Conferences, guest Editor of J. Magn. Magn. Mater, Phys. Stat. sol (A) and (C). A. Zhukov in collaboration with V. Zhukova wrote two books on magnetic properties and applications of glass-coated microwires, few book chapters, articles for the “Enciclopedia of NanoScience and Nanotechnology” and “Enciclopedia of Sensors”. Additionally Dr. A. Zhukov is the Editor of two books,. In 2000 A. Zhukov funded a spin-off company “TAMAG” involved in magnetic microsensors development. Most scientific activity is related to studies of magnetic properties of amorphous and nanocrystalline glass-coated microwires such as Giant Magnetoimpedance, GMI, effect and fast domain wall propagation.