Alloys of potassium

Alloys of potassium: - Potassium is a chemical element. It has the symbol K (Latin: kalium, from Arabic: القَلْيَه‎ al-qalyah “plant ashes”, cf. Alkali from the same root), atomic number 19, and atomic mass 39.0983. Potassium was first isolated from potash, hence the name. Elemental potassium is a soft silvery-white metallic alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the evolved hydrogen.

Potassium in nature occurs only as ionic salt. As such, it is found dissolved in seawater, and as part of many minerals. Potassium ion is necessary for the function of all living cells, and is thus present in all plant and animal tissues. It is found in especially high concentrations in plant cells, and in a mixed diet, it is most highly concentrated in fruits.

In many respects, potassium and sodium are chemically similar, although they have very different functions in organisms in general, and in animal cells in particular.

Precautions: - Potassium reacts very violently with water producing hydrogen gas which then usually catches fire. Potassium is usually kept under a hydrocarbon oil such as mineral oil or kerosene to stop the metal from reacting with water vapour present in the air. Unlike lithium and sodium, however, potassium should not be stored under oil indefinitely. If stored longer than 6 months to a year, dangerous shock-sensitive peroxides can form on the metal and under the lid of the container, which can detonate upon opening. It is recommended that potassium, rubidium or caesium not be stored for longer than three months unless stored in an inert (oxygen free) atmosphere, or under vacuum.^[29]

As potassium reacts with water to produce highly flammable hydrogen gas, a potassium fire is only exacerbated by the addition of water, and only a few dry chemicals are effective for putting out such a fire (see the precaution section in sodium).

Potassium also produces potassium hydroxide (KOH) in the reaction with water. Potassium hydroxide is a strong alkali and so is a caustic hazard, causing burns.

Due to the highly reactive nature of potassium metal, it must be handled with great care, with full skin and eye protection being used and preferably an explosive resistant barrier between the user and the potassium.

Alloys of nickel

Alloys of nickel: - Nickel is a chemical element, with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. It is one of the four ferromagnetic elements at about room temperature. Its use has been traced as far back as 3500 BC, but it was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who initially mistook its ore for a copper mineral. Its most important ore minerals are laterites, including limonite and garnierite, and pentlandite. Major production sites include Sudbury region in Canada, New Caledonia and Russia. The metal is corrosion-resistant, finding many uses in alloys, as a plating, in the manufacture of coins, magnets and common household utensils, as a catalyst for hydrogenation, and in a variety of other applications. Enzymes of certain life-forms contain nickel as an active center making the metal essential for them.

Alloys of mercury

Alloys of mercury: - Mercury, is a chemical element with the symbol Hg (Latinized Greek: hydrargyrum, meaning watery or liquid silver) and atomic number 80. A heavy, silvery d-block metal, mercury is one of six elements that are liquid at or near room temperature and pressure. The others are the elements caesium, francium, gallium, bromine, and rubidium. Of the metals, only mercury is liquid at standard conditions for temperature and pressure with the melting point of −38.83°C and the boiling point of 356.73°C, making it one of the narrowest liquid range of any metal. Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, and other scientific apparatus, though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favour of alcohol-filled, digital, or thermistor-based instruments. It remains in use in a number of other ways in scientific and scientific research applications, and in amalgam material for dental restoration. Mercury is mostly obtained by reduction from the mineral cinnabar. Electricity is passed through mercury vapor to produce short-wave ultraviolet light which then causes the phosphor coated on the inside of the tube to fluoresce, making visible light.
Mercury occurs in deposits throughout the world as mercuric sulfide or cinnabar, source of the red pigment vermilion. It is highly toxic by ingestion or inhalation of the dust, and mercury poisoning can also result from exposure to soluble forms (such as mercuric chloride or methylmercury), inhalation of mercury vapour, or eating fish contaminated with mercury.

Alloys of lead

Alloys of lead: - Lead is a main-group element with symbol Pb (Latin: plumbum) and atomic number 82. Lead is a soft, malleable poor metal, also considered to be one of the heavy metals. Lead has a bluish-white color when freshly cut, but tarnishes to a dull grayish color when exposed to air. It has a shiny chrome-silver luster when melted into a liquid.
Lead is used in building construction, lead-acid batteries, bullets and shot, weights, and is part of solder, pewter, fusible alloys and radiation shields. Lead has the highest atomic number of all stable elements, although the next element, bismuth, has a half-life so long (longer than the estimated age of the universe) it can be considered stable. Like mercury, another heavy metal, lead is a potent neurotoxin that accumulates in soft tissues and bone over time. Lead poisoning was documented in ancient Rome, Greece, and China.

Alloys of iron

Alloys of iron: - Iron is a chemical element with the symbol Fe (Latin: ferrum) and atomic number 26. Iron is a group 8 and period 4 element. Iron is lustrous and silvery in color. It is soft, about 80 Brinell, relative to steel, which is about 140 Brinell. It is one of the few ferromagnetic elements.
Iron-56 is the second heaviest stable isotope produced by the alpha process in stellar nucleosynthesis, the heaviest being nickel-62; heavier elements require a supernova for their formation. Iron is the most abundant element in the core of red giants, and is the most abundant metal in iron meteorites and in the dense metal cores of planets such as Earth. Iron and iron alloys are also the most common ferromagnetic materials in everyday use.

Alloys of gold

Alloys of gold: - Gold is a chemical element with the symbol Au (Latin: aurum) and atomic number 79. It is a highly sought-after precious metal, having been used as money, as a store of value, in jewelry, in sculpture, and for ornamentation since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is dense, soft, shiny and the most malleable and ductile pure metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without rusting in air or water. It is one of the coinage metals and formed the basis for the gold standard used before the collapse of the Bretton Woods system in 1971.
Modern industrial uses include dentistry and electronics, where gold has traditionally found use because of its good resistance to oxidative corrosion. Chemically, gold is a transition metal and can form trivalent and univalent cations upon solvation. At STP it is attacked by aqua regia (a mixture of acids), forming chloroauric acid and by alkaline solutions of cyanide but not by single acids such as hydrochloric, nitric or sulphuric acids. Gold dissolves in mercury, forming amalgam alloys, but does not react with it. Gold is insoluble in nitric acid, which will dissolve silver and base metals, and is the basis of the gold refining technique known as "inquartation and parting". Nitric acid has long been used to confirm the presence of gold in items, and this is the origin of the colloquial term "acid test", referring to a gold standard test for genuine value.

Price records: - Since 1968 the price of gold on the open market has ranged widely, from a high of $850/oz ($27,300/kg) on January 21, 1980, to a low of $252.90/oz ($8,131/kg) on June 21, 1999 (London Gold Fixing). The 1980 high was not overtaken until January 3, 2008 when a new maximum of $865.35 per troy ounce was set (a.m. London Gold Fixing).[23] The current record price was set on March 17, 2008 at $1023.50/oz (am. London Gold Fixing).

Alloys of copper

Alloys of copper: - Copper alloys are alloys with copper as their principal component. They have high resistance to corrosion. Due to its high electric conductivity, pure electrolytic copper is used mostly for making of electrical cables.
Brasses: - A brass is an alloy of copper with zinc. Brasses are usually yellow in color. The zinc content can vary between few % to about 40%; as long as it is kept under 15%, it does not markedly decrease corrosion resistance of copper.
Brasses can be sensitive to selective leaching corrosion under certain conditions, when zinc is leached from the alloy (dezincification), leaving behind a spongy copper structure.
Bronzes: - A bronze is an alloy of copper and other metals, most often tin, but also aluminium and silicon.
Aluminium bronzes are alloys of copper and aluminium. The content of aluminium ranges mostly between 5-11%. Iron, nickel, manganese and silicon are sometimes added. They have higher strength and corrosion resistance than other bronzes, especially in marine environment, and have low reactivity to sulfur compounds. Aluminium forms a thin passivation layer on the surface of the metal.
Phosphor bronze
Nickel bronzes, e.g. nickel silver and cupronickel