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Vanadium Nitride
Vanadium nitride, VN, is a chemical compound of vanadium and nitrogen. Vanadium nitride is formed during the nitriding of steel and increases wear resistance. Another phase, V2N, also referred to as vanadium nitride, can be formed along with VN during nitriding. VN has a cubic, rock-salt structure. There is also a low-temperature form, which contains V4 clusters. The low-temperature phase results from a dynamic instability, when the energy of vibrational modes in the high-temperature NaCl-structure phase, are reduced below zero. It is a strong-coupled superconductor. Nanocrystalline vanadium nitride has been claimed to have potential for use in supercapacitors alt=Supercapacitor, upright=1.5, Schematic illustration of a supercapacitor upright=1.5, A diagram that shows a hierarchical classification of supercapacitors and capacitors of related types A supercapacitor (SC), also called an ultracapacitor, .... The properties of vanadium nitride depend sensitively on the stoichiom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cubic Crystal System
In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There are three main varieties of these crystals: *Primitive cubic (abbreviated ''cP'' and alternatively called simple cubic) *Body-centered cubic (abbreviated ''cI'' or bcc) *Face-centered cubic (abbreviated ''cF'' or fcc) Note: the term fcc is often used in synonym for the ''cubic close-packed'' or ccp structure occurring in metals. However, fcc stands for a face-centered cubic Bravais lattice, which is not necessarily close-packed when a motif is set onto the lattice points. E.g. the diamond and the zincblende lattices are fcc but not close-packed. Each is subdivided into other variants listed below. Although the ''unit cells'' in these crystals are conventionally taken to be cubes, the primitive unit cells often are not. Bravais lattices The three Bravais latices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearson Symbol
The Pearson symbol, or Pearson notation, is used in crystallography as a means of describing a crystal structure. It was originated by William Burton Pearson and is used extensively in Pearson's handbook of crystallographic data for intermetallic phases. The symbol is made up of two letters followed by a number. For example: * Diamond structure, cF8 * Rutile structure, tP6 Construction The two letters in the Pearson symbol specify the Bravais lattice, and more specifically, the lower-case letter specifies the Crystal system, crystal family, while the upper-case letter the Lattice (group), lattice type. The number at the end of the Pearson symbol gives the number of the atoms in the conventional unit cell (atoms which satisfy 1 > x,y,z \geq 0 for the atom's position (x,y,z) in the unit cell). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(III) Oxide
Vanadium(III) oxide is the inorganic compound with the formula V2O3. It is a black solid prepared by reduction of V2O5 with hydrogen or carbon monoxide. It is a basic oxide dissolving in acids to give solutions of vanadium (III) complexes. V2O3 has the corundum Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium, and chromium. It is a rock (geology), rock-forming mineral. It is a naturally transparency and translucency, transparent material, but ... structure. It is antiferromagnetic with a critical temperature of 160 K, below which there is an abrupt change in conductivity from metallic to insulating.E.M. Page, S.A.Wass (1994),''Vanadium:Inorganic and Coordination chemistry'', Encyclopedia of Inorganic Chemistry, John Wiley & Sons, This also distorts the crystal structure to a monoclinic space group: C2/c. Upon exposure to air it gradually converts into indigo-blue V2O4. In nature it occurs as the rare mineral kare ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium Carbide
Vanadium carbide is the inorganic compound with the formula . It is an extremely hard and refractory ceramic material. With a hardness of 9-9.5 Mohs, it is possibly the hardest metal-carbide known. It is of interest because it is prevalent in vanadium metal and alloys.Günter Bauer, Volker Güther, Hans Hess, Andreas Otto, Oskar Roidl, Heinz Roller, Siegfried Sattelberger "Vanadium and Vanadium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. Structure and preparation Being isomorphous with vanadium monoxide, it crystallizes in the rock salt structure. Because VC and VO are miscible, samples of VC typically contain an impurity of the oxide. It is produced by heating vanadium oxides with carbon at around 1000 °C. Vanadium carbide can be formed in the (111) orientation, when formed by radio frequency magnetron sputtering. Although VC is thermodynamically stable, it converts to at higher temperatures. Vanadium carbide is used as an ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium Nitride
Titanium nitride (TiN; sometimes known as tinite) is an extremely hard ceramic material, often used as a physical vapor deposition (PVD) coating on titanium alloys, steel, carbide, and aluminium components to improve the substrate's surface properties. Applied as a thin coating, TiN is used to harden and protect cutting and sliding surfaces, for decorative purposes (for its golden appearance), and as a non-toxic exterior for medical implants. In most applications a coating of less than is applied. Characteristics TiN has a Vickers hardness of 1800–2100, hardness of , a modulus of elasticity of , a thermal expansion coefficient of 9.35 K−1, and a superconducting transition temperature of 5.6 K. TiN oxidizes at 800 °C in a normal atmosphere. It is chemically stable at 20 °C, according to laboratory tests, but can be slowly attacked by concentrated acid solutions with rising temperatures. TiN has a brown color and appears gold when applied as a coati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(III) Nitride
Chromium nitride is a chemical compound of chromium and nitrogen with the formula CrN. It is very hard, and is extremely resistant to corrosion. It is an interstitial compound, with nitrogen atoms occupying the octahedral holes in the chromium lattice: as such, it is not strictly a chromium(III) compound nor does it contain nitride ions (N3−). Chromium forms a second interstitial nitride, dichromium nitride, Cr2N. Synthesis Chromium(III) nitride can be prepared by direct combination of chromium and nitrogen at 800 °C: :2 Cr + → 2 CrN It can also synthesize by Physical Vapour Deposition technique such as Cathodic arc deposition. Applications CrN is used as a coating material for corrosion resistance and in metal forming and plastic moulding applications. CrN is often used on medical implants and tools. CrN is also a valuable component in advanced multicomponent coating systems, such as CrAlN, for hard, wear-resistant applications on cutting tools. Magnetism The fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niobium Nitride
Niobium nitride is a compound of niobium and nitrogen (nitride) with the chemical formula NbN. At low temperatures (about 16 K) NbN becomes a superconductor, and is used in detectors for infrared light. Uses *Niobium nitride's main use is as a superconductor. **Detectors based on it can detect a single photon in the 1-10 micrometer section of the infrared spectrum, which is important for astronomy and telecommunications. It can detect changes up to 25 gigahertz. **Superconducting NbN nanowires can be used in particle detectors with high magnetic fields. *Niobium nitride is also used in absorbing anti-reflective coatings. *In 2015, it was reported that Panasonic Corp. has developed a photocatalyst based on niobium nitride that can absorb 57% of sunlight to support the decomposition of water to produce hydrogen gas as fuel for electrochemical fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydroge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken or new bonds formed or both. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium
Vanadium is a chemical element; it has Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer (passivation (chemistry), passivation) somewhat stabilizes the free metal against further oxidation. Spain, Spanish-Mexico, Mexican scientist Andrés Manuel del Río discovered compounds of vanadium in 1801 by analyzing a new lead-bearing mineral he called "brown lead". Though he initially presumed its qualities were due to the presence of a new element, he was later erroneously convinced by French chemist Hippolyte Victor Collet-Descotils that the element was just chromium. Then in 1830, Nils Gabriel Sefström generated chlorides of vanadium, thus proving there was a new element, and named it "vanadium" after the Scandinavian goddess of beauty and fertility, Vanadís (Freyja). The name was based on the wide range of colors fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. It is a common element in the universe, estimated at Abundance of the chemical elements, seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element chemical bond, bond to form N2, a colourless and odourless diatomic molecule, diatomic gas. N2 forms about 78% of Atmosphere of Earth, Earth's atmosphere, making it the most abundant chemical species in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772 and independently by Carl Wilhelm Scheele and Henry Cavendish at about the same time. The name was suggested by French chemist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitridization
Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface. These processes are most commonly used on low-alloy steels. They are also used on titanium, aluminium and molybdenum. Typical applications include gears, crankshafts, camshafts, cam followers, valve parts, extruder screws, die-casting tools, forging dies, extrusion dies, firearm components, injectors and plastic mold tools. Processes The processes are named after the medium used to donate. The three main methods used are: ''gas nitriding'', ''salt bath nitriding'', and ''plasma nitriding''. Gas nitriding In gas nitriding the donor is a nitrogen-rich gas, usually ammonia (NH3), which is why it is sometimes known as ''ammonia nitriding''. When ammonia comes into contact with the heated work piece it dissociates into nitrogen and hydrogen. The nitrogen then diffuses onto the surface of the material creating a nitride layer. This process has existed for near ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercapacitors
alt=Supercapacitor, upright=1.5, Schematic illustration of a supercapacitor upright=1.5, A diagram that shows a hierarchical classification of supercapacitors and capacitors of related types A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than solid-state capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and rechargeable batteries. It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries. Unlike ordinary capacitors, supercapacitors do not use the conventional solid dielectric, but rather, they use electrostatic double-layer capacitance and electrochemical pseudocapacitance, both of which contribute to the total energy storage of the capacitor. Supercapacitors are used in applicati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
