Metals in the context of Recrystallization temperature

• A ″ natural material a substance that comes from plants, animals, or the earth, and has not been made by humans.. Minerals and the metals that can be extracted from them (without further modification) are also considered to belong into this category. Natural materials are used as building materials and clothing. Types include:

• Biotic materials
  • Wood (rattan, bamboo, bark, etc.)
• Plant fiber (coir, ramie, sisal, cotton, flax, hemp, jute, kapok, kenaf, moss, linen, abacá, etc.)
• Animal fiber (wool, silk, alpaca, camel, angora, cashmere, mohair, etc.)
• Inorganic material
  • Stone (flint, granite, limestone, obsidian, sandstone, sand, gems, glass, etc.)
  • Native metal (copper, iron, gold, silver, etc.)
  • Composites (clay, plasticine, etc.)
• Other natural materials.
  • Soil

Arsenical bronze is an alloy in which arsenic, as opposed to or in addition to tin or other constituent metals, is combined with copper to make bronze. The use of arsenic with copper, either as the secondary constituent or with another component such as tin, results in a stronger final product and better casting behavior.

Copper ore is often naturally contaminated with arsenic; hence, the term "arsenical bronze" when used in archaeology is typically only applied to alloys with an arsenic content higher than 1% by weight, in order to distinguish it from potentially accidental additions of arsenic.

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in them having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.

The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. They can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation by atmospheric moisture and oxygen (and in the case of lithium, nitrogen). Because of their high reactivity, they must be stored under oil to prevent reaction with air, and are found naturally only in salts and never as the free elements. Caesium, the fifth alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones.

Tarnish is a thin layer of corrosion that forms over copper, brass, aluminum, magnesium, neodymium and other similar metals as their outermost layer undergoes a chemical reaction. Tarnish does not always result from the sole effects of oxygen in the air. For example, silver needs hydrogen sulfide to tarnish, although it may tarnish with oxygen over time. It often appears as a dull, gray or black film or coating over metal. Tarnish is a surface phenomenon that is self-limiting, unlike rust. Only the top few layers of the metal react. The layer of tarnish seals and protects the underlying layers from reacting.

Tarnish preserves the underlying metal in outdoor use, and in this form is called chemical patina, an example of which is the green or blue-green form of copper(II) carbonate known as verdigris. Unlike patina advantageous in applications such as copper roofing and copper, bronze, and brass statues and fittings exposed to the elements, a chemical patina may be considered undesirable, as on silverware, or a matter of taste or convention, as in toning on coins.

De re metallica (Latin for On the Nature of Metals [Minerals]) is a book in Latin cataloguing the state of the art of mining, refining, and smelting metals, published a year posthumously in 1556 due to a delay in preparing woodcuts for the text. The author was Georg Bauer, whose pen name was the Latinized Georgius Agricola ("Bauer" and "Agricola" being respectively the German and Latin words for "farmer"). The book remained the authoritative text on mining for 180 years after its publication. It was also an important chemistry text for the period and is significant in the history of chemistry.

Mining was typically left to professionals, craftsmen and experts who were not eager to share the experiential knowledge they had accumulated over centuries; this knowledge was passed down orally within a small group of technicians and mining overseers. In the Middle Ages, these people held the same leading role as the master builders of the great cathedrals, or were perhaps like alchemists; a small, cosmopolitan elite within which knowledge was guarded from the outside world. Only a few writers found it worth the effort to write about mining, and only in the Renaissance did this begin to change. With improved transport and the invention of the printing press, knowledge spread much faster than before. In 1500, the first printed book dedicated to mining engineering, called the Nützlich Bergbüchleyn ("The Useful Little Mining Book") was published by Ulrich Rülein von Calw. The most important works in this genre, however, were the twelve books of De Re Metallica.

An oven is a tool that is used to expose materials to a hot environment. Ovens contain a hollow chamber and provide a means of heating the chamber in a controlled way. In use since antiquity, they have been used to accomplish a wide variety of tasks requiring controlled heating. Because they are used for a variety of purposes, there are many different types of ovens. These types differ depending on their intended purpose and based upon how they generate heat.

Ovens are often used for cooking, usually baking, sometimes broiling; they can be used to heat food to a desired temperature. Ovens are also used in the manufacturing of ceramics and pottery; these ovens are sometimes referred to as kilns. Metallurgical furnaces are ovens used in the manufacturing of metals, while glass furnaces are ovens used to produce glass.

In chemistry, a reactivity series (or reactivity series of elements) is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to lowest. It is used to summarize information about the reactions of metals with acids and water, single displacement reactions and the extraction of metals from their ores.

A toe ring is a ring made out of metals and non-metals worn on any of the toes. The second toe of either foot is where they are worn most commonly. This is because proportionately it is the longest toe and thus the easiest toe to put a ring on and stay without being connected to anything else. In most western countries they are a relatively new fashion accessory, and typically have no symbolic meaning. They are usually worn with barefoot sandals, anklets, bare feet or flip flops.

Like finger rings, toe rings come in many shapes and forms, from intricately designed flowers embedded with jewels to simple bands. Fitted toe rings are rings that are of one size, whereas adjustable toe rings have a gap at the bottom so they can be easily made to fit snugly.

Self-healing materials are artificial or synthetically created substances that have the built-in ability to automatically repair damages to themselves without any external diagnosis of the problem or human intervention. Generally, materials will degrade over time due to fatigue, environmental conditions, or damage incurred during operation. Cracks and other types of damage on a microscopic level have been shown to change thermal, electrical, and acoustical properties of materials, and the propagation of cracks can lead to eventual failure of the material. In general, cracks are hard to detect at an early stage, and manual intervention is required for periodic inspections and repairs. In contrast, self-healing materials counter degradation through the initiation of a repair mechanism that responds to the micro-damage. Some self-healing materials are classed as smart structures, and can adapt to various environmental conditions according to their sensing and actuation properties.

Although the most common types of self-healing materials are polymers or elastomers, self-healing covers all classes of materials, including metals, ceramics, and cementitious materials. Healing mechanisms vary from an instrinsic repair of the material to the addition of a repair agent contained in a microscopic vessel. For a material to be strictly defined as autonomously self-healing, it is necessary that the healing process occurs without human intervention. Self-healing polymers may, however, activate in response to an external stimulus (light, temperature change, etc.) to initiate the healing processes.

Bi-metallic coins are coins consisting of two (bi-) metals or alloys, generally arranged with an outer ring around a contrasting center. The bi-metal form is typically used to protect against counterfeiting.

Common circulating examples include the European €1 and €2, United Kingdom £1 and £2, Canadian $2, South Africa R5, Egyptian £1, Turkish 1 lira and 50 kurus, Indian ₹10 and ₹20, Indonesian Rp1,000, Polish 2 and 5 zł, Czech 50 Kč, Hungarian 100 and 200 Ft, Bulgarian 1 and 2 lv., Hong Kong $10, Argentine $1 and $2, Brazilian R$1, Chilean $100 and $500, Colombian $500 and $1000, Peruvian S/2 and S/5, Albanian 100 Lekë, Thai 10 baht and all Mexican coins of $1 or higher denomination. For a more complete list, see List of bi-metallic coins.

Microparticles are particles between 0.1 and 100 μm in size. Commercially available microparticles are available in a wide variety of materials, including ceramics, glass, polymers, and metals. Microparticles encountered in daily life include pollen, sand, dust, flour, and powdered sugar. The study of microparticles has been called micromeritics, although this term is not very common.

Microparticles have a much larger surface-to-volume ratio than at the macroscale, and thus their behavior can be quite different. For example, metal microparticles can be explosive in air.

Digging, also referred to as excavation, is the process of using some implement such as claws, hands, manual tools or heavy equipment, to remove material from a solid surface, usually soil, sand or rock on the surface of Earth. Digging is actually the combination of two processes, the first being the breaking or cutting of the surface, and the second being the removal and relocation of the material found there. In a simple digging situation, this may be accomplished in a single motion, with the digging implement being used to break the surface and immediately fling the material away from the hole or other structure being dug.

Many kinds of animals engage in digging, either as part of burrowing behavior or to search for food or water under the surface of the ground. Historically, humans have engaged in digging for both of these reasons, and for a variety of additional reasons, such as engaging in agriculture and gardening, searching for minerals, metals, and other raw materials such as during mining and quarrying, preparing for construction, making fortifications and irrigation, and also excavations in archaeology, searching for fossils and rocks in palaeontology and geology and burial of the dead.

The Merensky Reef is a layer of igneous rock in the Bushveld Igneous Complex (BIC) in the North West, Limpopo, Gauteng and Mpumalanga provinces of South Africa which together with an underlying layer, the Upper Group 2 Reef (UG2), contains most of the world's known reserves of platinum group metals (PGMs) or platinum group elements (PGEs)—platinum, palladium, rhodium, ruthenium, iridium and osmium. The Reef is 46 cm thick and bounded by thin chromite seams or stringers. The composition consists predominantly of cumulate rocks, including leuconorite, anorthosite, chromitite, and melanorite.