Hot pressing provides higher density material. Chemical vapor deposition can place a film of a ceramic on another material. Cermets are ceramic particles containing some metals. The wear resistance of tools is derived from cemented carbides with the metal phase of cobalt and nickel typically added to modify properties.
Filaments are commonly used for reinforcement in composite materials. Another application of materials science in industry is making composite materials. These are structured materials composed of two or more macroscopic phases. Applications range from structural elements such as steel-reinforced concrete, to the thermal insulating tiles which play a key and integral role in NASA's Space Shuttle thermal protection system which is used to protect the surface of the shuttle from the heat of re-entry into the Earth's atmosphere.
RCC is a laminated composite material made from graphite rayon cloth and impregnated with a phenolic resin. After curing at high temperature in an autoclave, the laminate is pyrolized to convert the resin to carbon, impregnated with furfural alcohol in a vacuum chamber, and cured-pyrolized to convert the furfural alcohol to carbon.
To provide oxidation resistance for reuse ability, the outer layers of the RCC are converted to silicon carbide. Other examples can be seen in the "plastic" casings of television sets, cell-phones and so on. These plastic casings are usually a composite material made up of a thermoplastic matrix such as acrylonitrile butadiene styrene ABS in which calcium carbonate chalk, talc , glass fibers or carbon fibers have been added for added strength, bulk, or electrostatic dispersion. These additions may be termed reinforcing fibers, or dispersants, depending on their purpose.
Polymers are chemical compounds made up of a large number of identical components linked together like chains. They are an important part of materials science.
Polymers are the raw materials the resins used to make what are commonly called plastics and rubber. Plastics and rubber are really the final product, created after one or more polymers or additives have been added to a resin during processing, which is then shaped into a final form. Plastics which have been around, and which are in current widespread use, include polyethylene , polypropylene , polyvinyl chloride PVC , polystyrene , nylons , polyesters , acrylics , polyurethanes , and polycarbonates and also rubbers which have been around are natural rubber, styrene-butadiene rubber, chloroprene , and butadiene rubber.
Plastics are generally classified as commodity , specialty and engineering plastics. Polyvinyl chloride PVC is widely used, inexpensive, and annual production quantities are large. It lends itself to a vast array of applications, from artificial leather to electrical insulation and cabling, packaging , and containers. Its fabrication and processing are simple and well-established. The versatility of PVC is due to the wide range of plasticisers and other additives that it accepts.
The term "additives" in polymer science refers to the chemicals and compounds added to the polymer base to modify its material properties. Such plastics are valued for their superior strengths and other special material properties. They are usually not used for disposable applications, unlike commodity plastics. Specialty plastics are materials with unique characteristics, such as ultra-high strength, electrical conductivity, electro-fluorescence, high thermal stability, etc. The dividing lines between the various types of plastics is not based on material but rather on their properties and applications.
For example, polyethylene PE is a cheap, low friction polymer commonly used to make disposable bags for shopping and trash, and is considered a commodity plastic, whereas medium-density polyethylene MDPE is used for underground gas and water pipes, and another variety called ultra-high-molecular-weight polyethylene UHMWPE is an engineering plastic which is used extensively as the glide rails for industrial equipment and the low-friction socket in implanted hip joints.
The study of metal alloys is a significant part of materials science. Of all the metallic alloys in use today, the alloys of iron steel , stainless steel , cast iron , tool steel , alloy steels make up the largest proportion both by quantity and commercial value.
Iron alloyed with various proportions of carbon gives low, mid and high carbon steels. An iron-carbon alloy is only considered steel if the carbon level is between 0. For the steels, the hardness and tensile strength of the steel is related to the amount of carbon present, with increasing carbon levels also leading to lower ductility and toughness.
Heat treatment processes such as quenching and tempering can significantly change these properties, however. Cast Iron is defined as an iron—carbon alloy with more than 2. Nickel and Molybdenum are typically also found in stainless steels. Other significant metallic alloys are those of aluminium , titanium , copper and magnesium. Copper alloys have been known for a long time since the Bronze Age , while the alloys of the other three metals have been relatively recently developed.
Due to the chemical reactivity of these metals, the electrolytic extraction processes required were only developed relatively recently. The alloys of aluminium, titanium and magnesium are also known and valued for their high strength-to-weight ratios and, in the case of magnesium, their ability to provide electromagnetic shielding. These materials are ideal for situations where high strength-to-weight ratios are more important than bulk cost, such as in the aerospace industry and certain automotive engineering applications.
The study of semiconductors is a significant part of materials science. A semiconductor is a material that has a resistivity between a metal and insulator.
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Its electronic properties can be greatly altered through intentionally introducing impurities or doping. From these semiconductor materials, things such as diodes , transistors , light-emitting diodes LEDs , and analog and digital electric circuits can be built, making them materials of interest in industry. Semiconductor devices have replaced thermionic devices vacuum tubes in most applications. Semiconductor devices are manufactured both as single discrete devices and as integrated circuits ICs , which consist of a number—from a few to millions—of devices manufactured and interconnected on a single semiconductor substrate.
Of all the semiconductors in use today, silicon makes up the largest portion both by quantity and commercial value. Monocrystalline silicon is used to produce wafers used in the semiconductor and electronics industry. Second to silicon, gallium arsenide GaAs is the second most popular semiconductor used. Due to its higher electron mobility and saturation velocity compared to silicon, it is a material of choice for high-speed electronics applications.
These superior properties are compelling reasons to use GaAs circuitry in mobile phones, satellite communications, microwave point-to-point links and higher frequency radar systems. Other semiconductor materials include germanium , silicon carbide , and gallium nitride and have various applications. Materials science evolved—starting from the s—because it was recognized that to create, discover and design new materials, one had to approach it in a unified manner. The field thus maintains close relationships with these fields.
Also, many physicists, chemists and engineers also find themselves working in materials science. The field of materials science and engineering is important both from a scientific perspective, as well as from an engineering one. When discovering new materials, one encounters new phenomena that may not have been observed before. Hence, there is a lot of science to be discovered when working with materials. Materials science also provides a test for theories in condensed matter physics.
Materials are of the utmost importance for engineers, as the usage of the appropriate materials is crucial when designing systems. As a result, materials science is an increasingly important part of an engineer's education. The main branches of materials science stem from the three main classes of materials: ceramics, metals, and polymers. From Wikipedia, the free encyclopedia.
Interdisciplinary field which deals with discovery and design of new materials, primarily of physical and chemical properties of solids. Main article: History of materials science. Main article: Chemical bonding. Main article: Crystallography. Main article: Nanostructure.
Main article: Microstructure. Main article: List of materials properties. Main article: Thermodynamics.
Main article: Chemical kinetics. Main article: Nanomaterials. Main article: Biomaterial. Main article: Ceramic. Main article: Composite material.
Main article: Polymer. Main article: Alloy. Science portal Engineering portal.southtenipep.ml
Benzoic acid | C6H5COOH - PubChem
Bio-based material Biomaterial Bioplastic Carbon nanotube Composite material Forensic materials engineering List of emerging material science technologies List of materials science journals List of scientific journals — Materials science List of surface analysis methods Materials science in science fiction Nanomaterials Nanotechnology Semiconductor Thermal analysis methods Timeline of materials technology Tribology.
Archived from the original on A Search for Structure. MIT Press. August Retrieved 3 August Physics in Perspective.
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