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Ceramography
Ceramography is the art and science of preparation, examination and evaluation of ceramic microstructures. Ceramography can be thought of as the metallography of ceramics. The microstructure is the structure level of approximately 0.1 to 100 µm, between the minimum wavelength of visible light and the resolution limit of the naked eye. The microstructure includes most grains, secondary phases, grain boundaries, pores, micro-cracks and hardness microindentions. Most bulk mechanical, optical, thermal, electrical and magnetic properties are significantly affected by the microstructure. The fabrication method and process conditions are generally indicated by the microstructure. The root cause of many ceramic failures is evident in the microstructure. Ceramography is part of the broader field of materialography, which includes all the microscopic techniques of material analysis, such as metallography, petrography and plastography. Ceramography is usually reserved for high-performance c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallography
Metallography is the study of the physical structure and components of metals, by using microscopy. Ceramic and polymeric materials may also be prepared using metallographic techniques, hence the terms ceramography, plastography and, collectively, materialography. Preparing metallographic specimens The surface of a metallographic specimen is prepared by various methods of grinding, polishing, and etching. After preparation, it is often analyzed using optical or electron microscopy. Using only metallographic techniques, a skilled technician can identify alloys and predict material properties. Mechanical preparation is the most common preparation method. Successively finer abrasive particles are used to remove material from the sample surface until the desired surface quality is achieved. Many different machines are available for doing this grinding and polishing, which are able to meet different demands for quality, capacity, and reproducibility. A systematic prepara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, and brick. The earliest ceramics made by humans were pottery objects (''pots,'' ''vessels or vases'') or figurines made from clay, either by itself or mixed with other materials like silica, hardened and sintered in fire. Later, ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, amorphous ceramic coatings on top of the crystalline ceramic substrates. Ceramics now include domestic, industrial and building products, as well as a wide range of materials developed for use in advanced ceramic engineering, such as in semiconductors. The word "'' ceramic''" comes from the Greek word (), "of pottery" or "for pottery", from (), "potter's clay, tile, pottery". The earliest k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutectic Point
A eutectic system or eutectic mixture ( ) is a homogeneous mixture that has a melting point lower than those of the constituents. The lowest possible melting point over all of the mixing ratios of the constituents is called the ''eutectic temperature''. On a phase diagram, the eutectic temperature is seen as the eutectic point (see plot on the right). Non-eutectic mixture ratios would have different melting temperatures for their different constituents, since one component's lattice will melt at a lower temperature than the other's. Conversely, as a non-eutectic mixture cools down, each of its components would solidify (form a lattice) at a different temperature, until the entire mass is solid. Not all binary alloys have eutectic points, since the valence electrons of the component species are not always compatible, in any mixing ratio, to form a new type of joint crystal lattice. For example, in the silver-gold system the melt temperature (liquidus) and freeze temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grinding (abrasive Cutting)
Grinding is a type of abrasive machining process which uses a grinding wheel as cutting tool. A wide variety of machines are used for grinding, best classified as portable or stationary: * Portable power tools such as angle grinders, die grinders and cut-off saws * Stationary power tools such as bench grinders and cut-off saws * Stationary hydro- or hand-powered sharpening stones Milling practice is a large and diverse area of manufacturing and toolmaking. It can produce very fine finishes and very accurate dimensions; yet in mass production contexts, it can also rough out large volumes of metal quite rapidly. It is usually better suited to the machining of very hard materials than is "regular" machining (that is, cutting larger chips with cutting tools such as tool bits or milling cutters), and until recent decades it was the only practical way to machine such materials as hardened steels. Compared to "regular" machining, it is usually better suited to taking very sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASM International (society)
ASM International, formerly known as the American Society for Metals, is an association of materials-centric engineers and scientists. ASM provides several information resources, including technical books, various digital databases, and ASM Handbooks, a series of reference books that cover a range of topics and contain peer-reviewed information. These handbooks are recognized as a standard reference in the field of materials science. Examples of topics covered by the ASM Handbooks are mechanical properties of metals, corrosion studies, failure analysis, materials characterization, and much more. Other publications include technical journals such as Journal of Thermal Spray Technology and Journal of Materials Engineering and Performance. ASM also hosts numerous international conferences each year, including ASM's Annual Meeting: International Materials, Applications, and Technologies Conference and Exposition (IMAT). Six affiliate societies focused on specific areas of material ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Atomic Energy Commission
The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by U.S. Congress to foster and control the peacetime development of atomic science and technology. President Harry S. Truman signed the McMahon/Atomic Energy Act on August 1, 1946, transferring the control of atomic energy from military to civilian hands, effective on January 1, 1947. This shift gave the members of the AEC complete control of the plants, laboratories, equipment, and personnel assembled during the war to produce the atomic bomb. An increasing number of critics during the 1960s charged that the AEC's regulations were insufficiently rigorous in several important areas, including radiation protection standards, nuclear reactor safety, plant siting, and environmental protection. By 1974, the AEC's regulatory programs had come under such strong attack that the U.S. Congress decided to abolish the AEC. The AEC was abolished by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia University
Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhattan, Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States. It is one of nine colonial colleges founded prior to the Declaration of Independence. It is a member of the Ivy League. Columbia is ranked among the top universities in the world. Columbia was established by royal charter under George II of Great Britain. It was renamed Columbia College in 1784 following the American Revolution, and in 1787 was placed under a private board of trustees headed by former students Alexander Hamilton and John Jay. In 1896, the campus was moved to its current location in Morningside Heights and renamed Columbia University. Columbia scientists and scholars hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrolytic
An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dissolving, the substance separates into cations and anions, which disperse uniformly throughout the solvent. Solid-state electrolytes also exist. In medicine and sometimes in chemistry, the term electrolyte refers to the substance that is dissolved. Electrically, such a solution is neutral. If an electric potential is applied to such a solution, the cations of the solution are drawn to the electrode that has an abundance of electrons, while the anions are drawn to the electrode that has a deficit of electrons. The movement of anions and cations in opposite directions within the solution amounts to a current. Some gases, such as hydrogen chloride (HCl), under conditions of high temperature or low pressure can also function as electrolytes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holger F
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Holger may refer to: People * Holger (given name), includes name origin, plus people with the name * Hilde Holger, stage name of dancer, choreographer and dance teacher Hilde Boman-Behram (née Hilde Sofer, 1905–2001) Fictional characters * Holger Danske, a legendary Danish hero Other uses * Holger Danske (Resistance group) * Holger Danske (opera) * 9266 Holger, a main-belt asteroid * Radio Holger Radio Holger was a Danish radio station transmitting in Metropolitan Copenhagen The Copenhagen metropolitan area or Metropolitan Copenhagen ( da, Hovedstadsområdet, , literally "The Capital Area") is a large commuter belt (the area in which it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Institute Of Standards And Technology
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into Outline of physical science, physical science laboratory programs that include Nanotechnology, nanoscale science and technology, engineering, information technology, neutron research, material measurement, and physical measurement. From 1901 to 1988, the agency was named the National Bureau of Standards. History Background The Articles of Confederation, ratified by the colonies in 1781, provided: The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States. Article 1, section 8, of the Constitution of the United States, ratified in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vickers
Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 1867, acquired more businesses, and began branching out into military hardware and shipbuilding. In 1911, the company expanded into aircraft manufacture and opened a flying school. They expanded even further into electrical and railway manufacturing, and in 1928 acquired an interest in the Supermarine. Beginning in the 1960s, various parts of the company were nationalised, and in 1999 the rest of the company was acquired by Rolls-Royce plc, who sold the defence arm to Alvis plc. The Vickers name lived on in Alvis Vickers, until the latter was acquired by BAE Systems in 2004 to form BAE Systems Land Systems. History Early history Vickers was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law George Naylo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brinell Scale
The Brinell scale characterizes the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hardness in materials science. History Proposed by Swedish engineer Johan August Brinell in 1900, it was the first widely used and standardised hardness test in engineering and metallurgy. The large size of indentation and possible damage to test-piece limits its usefulness. However, it also had the useful feature that the hardness value divided by two gave the approximate UTS in ksi for steels. This feature contributed to its early adoption over competing hardness tests. Test details The typical test uses a diameter steel ball as an indenter with a force. For softer materials, a smaller force is used; for harder materials, a tungsten carbide ball is substituted for the steel ball. The indentation is measured and hardness calculated as: :\operatorname=\frac where: :BHN = Brinell Hard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
