|
Flux (metallurgy)
In metallurgy, a flux is a chemical reducing agent, flowing agent, or purifying agent. Fluxes may have more than one function at a time. They are used in both extractive metallurgy and metal joining. Some of the earliest known fluxes were sodium carbonate, potash, charcoal, coke, borax, lime, lead sulfide and certain minerals containing phosphorus. Iron ore was also used as a flux in the smelting of copper. These agents served various functions, the simplest being a reducing agent, which prevented oxides from forming on the surface of the molten metal, while others absorbed impurities into slag, which could be scraped off molten metal. Fluxes are also used in foundries for removing impurities from molten nonferrous metals such as aluminium, or for adding desirable trace elements such as titanium. As reducing agents, fluxes facilitate soldering, brazing, and welding by removing oxidation from the metals to be joined. In some applications molten flux also serves as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kolophonium Loeten
Rosin (), also known as colophony or Greek pitch (), is a resinous material obtained from pine trees and other plants, mostly conifers. The primary components of rosin are diterpenoids, i.e., C20 carboxylic acids. Rosin consists mainly of resin acids, especially abietic acid. Rosin often appears as a semi-transparent, brittle substance that ranges in color from yellow to black and melts at stove-top temperatures. In addition to industrial applications such as in varnishes, adhesives, and sealing wax, rosin is used with string instruments on the bow hair to enhance its ability to grip and sound the strings, and it provides grip in various sports and activities. Rosin also serves as an ingredient in medicinal and pharmaceutical formulations and can cause contact dermatitis or occupational asthma in sensitive individuals. It is an FDA approved food additive. The name "colophony" originates from , Latin for "resin from Colophon" (), an ancient Ionic city. Properties Rosin i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smelting
Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron-making, iron, copper extraction, copper, silver mining#Ore processing, silver, tin, lead smelting, lead and zinc smelting, zinc. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal behind. The reducing agent is commonly a fossil-fuel source of carbon, such as carbon monoxide from incomplete combustion of coke (fuel), coke—or, in earlier times, of charcoal. The oxygen in the ore binds to carbon at high temperatures, as the Chemical energy, chemical potential energy of the bonds in carbon dioxide () is lower than that of the bonds in the ore. Sulfide ores such as those commonly used to obtain copper, zinc or lead, are roasting (metallurgy), roasted before smelting in order to convert the sulfid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wetting
Wetting is the ability of a liquid to displace gas to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. These interactions occur in the presence of either a gaseous phase or another liquid phase not miscible with the wetting liquid. The degree of wetting (wettability) is determined by a force balance between adhesive and cohesive forces. There are two types of wetting: non-reactive wetting and reactive wetting. Wetting is important in the bonding or adherence of two materials. The wetting power of a liquid, and surface forces which control wetting, are also responsible for related effects, including capillary effects. Surfactants can be used to increase the wetting power of liquids such as water. Wetting has gained increasing attention in nanotechnology and nanoscience research, following the development of nanomaterials over the past two decades (i.e., graphene, carbon nanotube, boron nitride nanomesh). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redox
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. The oxidation and reduction processes occur simultaneously in the chemical reaction. There are two classes of redox reactions: * Electron transfer, Electron-transfer – Only one (usually) electron flows from the atom, ion, or molecule being oxidized to the atom, ion, or molecule that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * Atom transfer – An atom transfers from one Substrate (chemistry), substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously, the oxidation state of oxygen decreases as it accepts electrons r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. The oxidation and reduction processes occur simultaneously in the chemical reaction. There are two classes of redox reactions: * Electron-transfer – Only one (usually) electron flows from the atom, ion, or molecule being oxidized to the atom, ion, or molecule that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * Atom transfer – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously, the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welding
Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, primarily by using high temperature to melting, melt the parts together and allow them to cool, causing Fusion welding, fusion. Common alternative methods include solvent welding (of thermoplastics) using chemicals to melt materials being bonded without heat, and #Solid-state welding, solid-state welding processes which bond without melting, such as pressure, cold welding, and diffusion bonding. Metal welding is distinct from lower temperature bonding techniques such as brazing and soldering, which do not melt the base metal (parent metal) and instead require flowing a filler metal to solidify their bonds. In addition to melting the base metal in welding, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that can be stronger than the base material. Welding also requires a form of shield to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazing
Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal. Brazing differs from welding in that it does not involve melting the work pieces. Brazing differs from soldering through the use of a higher temperature and much more closely fitted parts. During the brazing process, the filler metal flows into the gap between close-fitting parts by capillary action. The filler metal is brought slightly above its melting ( liquidus) temperature while protected by a suitable atmosphere, usually a flux. It then flows over the base metal (in a process known as wetting) and is then cooled to join the work pieces together. Brazing joins the same or different metals with considerable strength. Process Brazing has many advantages over other metal-joining techniques, such as welding. Since brazing does not melt the base metal of the joi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soldering
Soldering (; ) is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creating a strong and durable joint. Soldering is commonly used in the electronics industry for the manufacture and repair of Printed circuit board, printed circuit boards (PCBs) and other electronic components. It is also used in plumbing and Metalworking, metalwork, as well as in the manufacture of jewelry and other decorative items. The solder used in the process can vary in composition, with different alloys used for different applications. Common solder alloys include tin-lead, tin-silver, and tin-copper, among others. Lead-free solder has also become more widely used in recent years due to health and environmental concerns associated with the use of lead. In addition to the type of solder used, the temperature and method of heating also p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium
Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of minerals, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide (TiO2), is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and cata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has a great affinity towards oxygen, passivation (chemistry), forming a protective layer of aluminium oxide, oxide on the surface when exposed to air. It visually resembles silver, both in its color and in its great ability to reflect light. It is soft, magnetism, nonmagnetic, and ductility, ductile. It has one stable isotope, 27Al, which is highly abundant, making aluminium the abundance of the chemical elements, 12th-most abundant element in the universe. The radioactive decay, radioactivity of aluminium-26, 26Al leads to it being used in radiometric dating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonferrous Metal
In metallurgy, non-ferrous metals are metals or alloys that do not contain iron ( allotropes of iron, ferrite, and so on) in appreciable amounts. Generally more costly than ferrous metals, non-ferrous metals are used because of desirable properties such as low weight (e.g. aluminium), higher conductivity (e.g. copper), non-magnetic properties or resistance to corrosion (e.g. zinc). Some non-ferrous materials are also used in the iron and steel industries. For example, bauxite is used as flux for blast furnaces, while others such as wolframite, pyrolusite, and chromite are used in making ferrous alloys. Important non-ferrous metals include aluminium, copper, lead, tin, titanium, and zinc, and alloys such as brass. Precious metals such as gold, silver, and platinum and exotic or rare metals such as mercury, tungsten, beryllium, bismuth, cerium, cadmium, niobium, indium, gallium, germanium, lithium, selenium, tantalum, tellurium, vanadium, and zirconium are also non-ferrous. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foundry
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed. Foundries are one of the largest contributors to the manufacturing recycling movement, melting and recasting millions of tons of scrap metal every year to create new durable goods. Moreover, many foundries use sand in their molding process. These foundries often use, recondition, and reuse sand, which is another form of recycling. Process In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
