58 Materials

Aerospace materials are materials, frequently metal alloys, that have either been developed for, or have come to prominence through, their use for aerospace purposes.

Agricultural lime, also called aglime, agricultural limestone, garden lime or liming, is a soil additive made from pulverized limestone or chalk. The primary active component is calcium carbonate. Additional chemicals vary depending on the mineral source and may include calcium oxide. Unlike the types of lime called quicklime and slaked lime, powdered limestone does not require lime burning in a lime kiln; it only requires milling. All of these types of lime are sometimes used as soil conditioners, with a common theme of providing a base to correct acidity, but lime for farm fields today is often crushed limestone. Historically, liming of farm fields in centuries past was often done with burnt lime; the difference is at least partially explained by the fact that affordable mass-production-scale fine milling of stone and ore relies on technologies developed since the mid-19th century.

Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage, marine hull reinforcement, and as an asbestos substitute. The name is a blend of "aromatic polyamide".

Auxetics are structures or materials that have a negative Poisson's ratio. When stretched, they become thicker perpendicular to the applied force. This occurs due to their particular internal structure and the way this deforms when the sample is uniaxially loaded. Auxetics can be single molecules, crystals, or a particular structure of macroscopic matter. Such materials and structures are expected to have mechanical properties such as high energy absorption and fracture resistance. Auxetics may be useful in applications such as body armor, packing material, knee and elbow pads, robust shock absorbing material, and sponge mops.

Baby powder is an astringent powder used for preventing diaper rash and for cosmetic uses. It may be composed of talcum or corn starch. Baby powder can also be used as a dry shampoo, cleaning agent, and freshener.

A Bingham plastic is a viscoplastic material that behaves as a rigid body at low stresses but flows as a viscous fluid at high stress. It is named after Eugene C. Bingham who proposed its mathematical form.

A Bouligand structure is a layered and rotated microstructure resembling plywood, which is frequently found in naturally designed materials. It consists of multiple lamellae, or layers, each one composed of aligned fibers. Adjacent lamellae are progressively rotated with respect to their neighbors. This structure enhances the mechanical properties of materials, especially its fracture resistance, and enables strength and in plane isotropy. It is found in various natural structures including the cosmoid scale of the coelacanth, and the dactyl club of the mantis shrimp and many other stomatopods.

A chemiresistor is a material that changes its electrical resistance in response to changes in the nearby chemical environment. Chemiresistors are a class of chemical sensors that rely on the direct chemical interaction between the sensing material and the analyte. The sensing material and the analyte can interact by covalent bonding, hydrogen bonding, or molecular recognition. Several different materials have chemiresistor properties: metal-oxide semiconductors, some conductive polymers, and nanomaterials like graphene, carbon nanotubes and nanoparticles. Typically these materials are used as partially selective sensors in devices like electronic tongues or electronic noses.

Cork is an impermeable buoyant material, the phellem layer of bark tissue that is harvested for commercial use primarily from Quercus suber, which is native to southwest Europe and northwest Africa. Cork is composed of suberin, a hydrophobic substance. Because of its impermeable, buoyant, elastic, and fire retardant properties, it is used in a variety of products, the most common of which is wine stoppers. The montado landscape of Portugal produces approximately half of cork harvested annually worldwide, with Corticeira Amorim being the leading company in the industry. Cork was examined microscopically by Robert Hooke, which led to his discovery and naming of the cell.

D3O is an ingredient brand specialising in advanced impact protection technologies, materials and products. It comprises a portfolio of more than 30 technologies and materials including set foams, formable foams, set elastomers and formable elastomers.

Devoré is a fabric technique particularly used on velvets, where a mixed-fibre material undergoes a chemical process to dissolve the cellulose fibers to create a semi-transparent pattern against more solidly woven fabric. The same technique can also be applied to textiles other than velvet, such as lace or the fabrics in burnout t-shirts.

Dimitris Drikakis, PhD, FRAeS, CEng, is a Greek-British applied scientist, engineer and university professor. His research is multidisciplinary. It covers fluid dynamics, computational fluid dynamics, acoustics, heat transfer, computational science from molecular to macro scale, materials, machine learning, and emerging technologies. He has applied his research to diverse fields such as Aerospace & Defence, Biomedical, and Energy and Environment Sectors. He received The William Penney Fellowship Award by the Atomic Weapons Establishment to recognise his contributions to compressible fluid dynamics. He was also the winner of NEF's Innovator of the Year Award by the UK's Institute of Innovation and Knowledge Exchange for a new generation carbon capture nanotechnology that uses carbon nanotubes for filtering out carbon dioxide and other gases.

Ebonite is a brand name for a material generically known as hard rubber, and is obtained by vulcanizing natural rubber for prolonged periods. Ebonite may contain from 25% to 80% sulfur and linseed oil. Its name comes from its intended use as an artificial substitute for ebony wood. The material has also been called vulcanite, although that name formally refers to the mineral vulcanite.

Fiber or fibre is a natural or man-made substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene.

Filler materials are particles added to resin or binders that can improve specific properties, make the product cheaper, or a mixture of both. The two largest segments for filler material use is elastomers and plastics. Worldwide, more than 53 million tons of fillers are used every year in application areas such as paper, plastics, rubber, paints, coatings, adhesives, and sealants. As such, fillers, produced by more than 700 companies, rank among the world's major raw materials and are contained in a variety of goods for daily consumer needs. The top filler materials used are ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), kaolin, talc, and carbon black. Filler materials can affect the tensile strength, toughness, heat resistance, color, clarity etc. A good example of this is the addition of talc to polypropylene. Most of the filler materials used in plastics are mineral or glass based filler materials. Particulates and fibers are the main subgroups of filler materials. Particulates are small particles of filler which are mixed in the matrix where size and aspect ratio are important. Fibers are small circular strands that can be very long and have very high aspect ratios.

Food contact materials are materials that are intended to be in contact with food. These can be things that are quite obvious like a glass or a can for soft drinks as well as machinery in a food factory or a coffee machine.

A gemstone is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks and occasionally organic materials that are not minerals are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone.

Glass is a non-crystalline, often transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of the molten form; some glasses such as volcanic glass are naturally occurring. The most familiar, and historically the oldest, types of manufactured glass are "silicate glasses" based on the chemical compound silica, the primary constituent of sand. Soda-lime glass, containing around 70% silica, accounts for around 90% of manufactured glass. The term glass, in popular usage, is often used to refer only to this type of material, although silica-free glasses often have desirable properties for applications in modern communications technology. Some objects, such as drinking glasses and eyeglasses, are so commonly made of silicate-based glass that they are simply called by the name of the material.

Glass microspheres are microscopic spheres of glass manufactured for a wide variety of uses in research, medicine, consumer goods and various industries. Glass microspheres are usually between 1 and 1000 micrometers in diameter, although the sizes can range from 100 nanometers to 5 millimeters in diameter. Hollow glass microspheres, sometimes termed microballoons or glass bubbles, have diameters ranging from 10 to 300 micrometers.

Hybrid wood or wood hybrid systems (WHS) is a multilayer composite material, composed on the surface of a skin made of composite wood (WPC) adhering to an underneath structural core, in general aluminum. Invented in Japan in 2008, this technological evolution is based on wood composite technology which was conceived in 1972 by Sadao Nishibori and patented in 1983 to substitute threatened exotic wood species. WHS are not fibre-reinforced plastic (FRP).

An electrical insulator is a material in which the electron does not flow freely or the atom of the insulator have tightly bound electrons whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field. This contrasts with other materials, semiconductors and conductors, which conduct an electric current more easily. The property that distinguishes an insulator is its resistivity; insulators have higher resistivity than semiconductors or conductors. The most common examples are non-metals.

Iron(II) hydroxide or ferrous hydroxide is an inorganic compound with the formula Fe(OH)2. It is produced when iron(II) salts, from a compound such as iron(II) sulfate, are treated with hydroxide ions. Iron(II) hydroxide is a white solid, but even traces of oxygen impart a greenish tinge. The air-oxidised solid is sometimes known as "green rust".

A J-aggregate is a type of dye with an absorption band that shifts to a longer wavelength of increasing sharpness when it aggregates under the influence of a solvent or additive or concentration as a result of supramolecular self-organisation. The dye can be characterized further by a small Stokes shift with a narrow band. The J in J-aggregate refers to E.E. Jelley who discovered the phenomenon in 1936. The dye is also called a Scheibe aggregate after G. Scheibe who also independently published on this topic in 1937.

Latex is a stable dispersion (emulsion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well.

Layered double hydroxides (LDH) are a class of ionic solids characterized by a layered structure with the generic layer sequence [AcB Z AcB]n, where c represents layers of metal cations, A and B are layers of hydroxide anions, and Z are layers of other anions and neutral molecules. Lateral offsets between the layers may result in longer repeating periods.

Lute was a substance used to seal and affix apparatus employed in chemistry and alchemy, and to protect component vessels against heat damage by fire; it was also used to line furnaces. Lutation was thus the act of "cementing vessels with lute".

Materials for use in vacuum are materials that show very low rates of outgassing in vacuum and, where applicable, are tolerant to bake-out temperatures. The requirements grow increasingly stringent with the desired degree of vacuum to be achieved in the vacuum chamber. The materials can produce gas by several mechanisms. Molecules of gases and water can be adsorbed on the material surface. Materials may sublimate in vacuum. Or the gases can be released from porous materials or from cracks and crevices. Traces of lubricants, residues from machining, can be present on the surfaces. A specific risk is outgassing of solvents absorbed in plastics after cleaning.

A mesoporous material is a material containing pores with diameters between 2 and 50 nm, according to IUPAC nomenclature. For comparison, IUPAC defines microporous material as a material having pores smaller than 2 nm in diameter and macroporous material as a material having pores larger than 50 nm in diameter.

Milk fiber or milk wool is a type of Azlon a regenerated protein fiber based on the casein protein found in milk. There are several trade names for milk casein based fibers including Lanital, Fibrolane and Aralac.

Mineral wool is any fibrous material formed by spinning or drawing molten mineral or rock materials such as slag and ceramics.

Muka is prepared fibre of New Zealand flax. Prepared primarily by scraping, pounding and washing, it is a key material in Māori traditional textiles where it is usually used in tāniko or twined weaving.

A (Plant)natural rope is a rope that is made from natural fibers. These fibers are obtained from organic material. Natural ropes suffer from many problems including susceptibility to rotting, degradation, mildew and wear out very quickly.

Noil is the short fiber left over from combing wool or spinning silk and used as a decorative additive for many spinning projects like rovings and yarns. Silk noil is also called "raw silk", although that is a misnomer. As noil is a relatively short fiber, fabric made from noil is weaker and considered less valuable.

In material science and solid mechanics, orthotropic materials have material properties at a particular point, which differ along three mutually-orthogonal axes, where each axis has twofold rotational symmetry. These directional differences in strength can be quantified with Hankinson's equation.

In physics, a paste is a substance that behaves as a solid until a sufficiently large load or stress is applied, at which point it flows like a fluid. In rheological terms, a paste is an example of a Bingham plastic fluid.

A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo, milk, and ink. The size ranges from very small bottles to large carboys. Consumer blow molded containers often have integral handles or are shaped to facilitate grasping.

A porous medium or a porous material is a material containing pores (voids). The skeletal portion of the material is often called the "matrix" or "frame". The pores are typically filled with a fluid. The skeletal material is usually a solid, but structures like foams are often also usefully analyzed using concept of porous media.

Putty is a material with high plasticity, similar in texture to clay or dough, typically used in domestic construction and repair as a sealant or filler. Although some types of putty slowly polymerise and become stiff, many putties can be reworked indefinitely, in contrast to other types of filler which typically set solid relatively rapidly.

A radiant barrier is a type of building material that reflects thermal radiation and reduces heat transfer. Because thermal energy is also transferred by conduction and convection, in addition radiation, radiant barriers are often supplemented with thermal insulation that slows down heat transfer by conduction or convection.

Radiation-absorbent material, usually known as RAM, is a material which has been specially designed and shaped to absorb incident RF radiation, as effectively as possible, from as many incident directions as possible. The more effective the RAM, the lower the resulting level of reflected RF radiation. Many measurements in electromagnetic compatibility (EMC) and antenna radiation patterns require that spurious signals arising from the test setup, including reflections, are negligible to avoid the risk of causing measurement errors and ambiguities.

A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished products, energy, or intermediate materials that are feedstock for future finished products. As feedstock, the term connotes these materials are bottleneck assets and are required to produce other products.

A refractory material or refractory is a material that is resistant to decomposition by heat, pressure, or chemical attack, and retains strength and form at high temperatures. Refractories are polycrystalline, polyphase, inorganic, nonmetallic, porous, and heterogeneous. They are typically composed of oxides or non oxides like carbides, nitrides etc. of the following materials: silicon, aluminium, magnesium, calcium, and zirconium. Some metals with melting points >1850 °C like niobium, chromium, zirconium, tungsten, rhenium, tantalum etc. are also considered as refractories.

Rice hulls are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, or fuel. Rice hulls are part of the chaff of the rice.

A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition and the way in which it is formed. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere.

Rubblization is a construction and engineering technique that involves saving time and transportation costs by reducing existing concrete into rubble at its current location rather than hauling it to another location. Rubblization has two primary applications: creating a base for new roadways and decommissioning nuclear power plants.

A safety data sheet (SDS), material safety data sheet (MSDS), or product safety data sheet (PSDS) is a document that lists information relating to occupational safety and health for the use of various substances and products. SDSs are a widely used system for cataloguing information on chemicals, chemical compounds, and chemical mixtures. SDS information may include instructions for the safe use and potential hazards associated with a particular material or product, along with spill-handling procedures. The older MSDS formats could vary from source to source within a country depending on national requirements; however, the newer SDS format is internationally standardized.

Sealant is a substance used to block the passage of fluids through the surface or joints or openings in materials, a type of mechanical seal. In building construction sealant is sometimes synonymous with caulking and also serve the purposes of blocking dust, sound and heat transmission. Sealants may be weak or strong, flexible or rigid, permanent or temporary. Sealants are not adhesives but some have adhesive qualities and are called adhesive-sealants or structural sealants.

A semimetal is a material with a very small overlap between the bottom of the conduction band and the top of the valence band. According to electronic band theory, solids can be classified as insulators, semiconductors, semimetals, or metals. In insulators and semiconductors the filled valence band is separated from an empty conduction band by a band gap. For insulators, the magnitude of the band gap is larger than that of a semiconductor. Because of the slight overlap between the conduction and valence bands, semimetal has no band gap and a negligible density of states at the Fermi level. A metal, by contrast, has an appreciable density of states at the Fermi level because the conduction band is partially filled.

A slurry is a mixture of solids denser than water suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids, the liquid being a carrier that is pumped on a device such as a centrifugal pump. The size of solid particles may vary from 1 micron up to hundreds of millimeters.

Solid surface is a man-made material usually composed of a combination of alumina trihydrate (ATH), acrylic, epoxy or polyester resins and pigments. It is most frequently used for seamless countertop installations.

A space blanket is an especially low-weight, low-bulk blanket made of heat-reflective, thin, plastic sheeting. They are used on the exterior surfaces of spacecraft for thermal control, as well as by people. Their design reduces the heat loss in a person's body, which would otherwise occur due to thermal radiation, water evaporation, or convection. Their low weight and compact size before unfurling make them ideal when space or weight are at a premium. They may be included in first aid kits and with camping equipment. Lost campers and hikers have an additional possible benefit: the shiny surface flashes in the sun, allowing its use as an improvised distress beacon for searchers and as a method of signalling over long distances to other people.

Structural engineering depends on the knowledge of materials and their properties, in order to understand how different materials resist and support loads.

A superhard material is a material with a hardness value exceeding 40 gigapascals (GPa) when measured by the Vickers hardness test. They are virtually incompressible solids with high electron density and high bond covalency. As a result of their unique properties, these materials are of great interest in many industrial areas including, but not limited to, abrasives, polishing and cutting tools, disc brakes, and wear-resistant and protective coatings.

Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat.

In microfabrication, thermal oxidation is a way to produce a thin layer of oxide on the surface of a wafer. The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it. The rate of oxide growth is often predicted by the Deal–Grove model. Thermal oxidation may be applied to different materials, but most commonly involves the oxidation of silicon substrates to produce silicon dioxide.

Tortoiseshell or tortoise shell is a material produced from the shells of the larger species of tortoise and turtle, mainly the hawksbill sea turtle, which is a critically endangered species according to the IUCN Red List largely because of its exploitation for this trade. The large size, fine colour and unusual form of the hawksbill's scutes make it especially suitable. The distinctive patterning is referred to in names such as the tortoiseshell cat, several breeds of guinea pig, and the common names of several species of the butterfly genera Nymphalis and Aglais, and some other uses.

Wattle is a lightweight construction material made by weaving thin branches or slats between upright stakes to form a woven lattice. It has commonly been used to make fences and hurdles for enclosing ground or handling livestock. The wattle may be made as loose panels, slotted between timber framing to make infill panels, or it may be made in place to form the whole of a fence or wall. The technique goes back to Neolithic times.

Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic material – a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber.