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Ceramics Traditional ceramic materials are generally divided into two basic

Ceramics Traditional ceramic materials are generally divided into two basic categories of ceramics and modern generation. Traditional means of natural silicate ceramic powder (allying as clay, Kaolin Etc.) as raw aim. Because the dummy of raw materials mixed and volatile performance of the product, only for Tableware, family containers, crafts, also the general Building Materials (such as Tiles, span Etc.), does not observe to industrial use. Ceramics of modern technology is based on the required performance, through decent control of composition and production process created by high-performance materials, mainly for high coldness and corrosive media environments, the development of modern components break one of the immeasurably lively areas. The following modern specialized ceramics three main areas: structural ceramics, ceramic matrix composites again functional ceramics for a brief introduction. ‚€š‚  A structural ceramic in comparison with metal materials, ceramics biggest advantage is excellent high temperature mechanical properties, chemical resistance, high temperature oxidation resistance, wear and tear, the proportion of meagre (about metal 1 / 3), which in many occasions gradually replacing expensive high alloy steel or metal materials could not impersonate applied to competent occasions, such considering Engine conduit Sets, bearings, seals, ceramic cutting Tools further then on. Structural ceramics pledge be divided pursuit three categories: oxide ceramics, non-oxide ceramics and glass Ceramics. 1, oxide ceramics major Package include Alumina, Zirconia, mullite and aluminum titanate. The very much choice advantage of oxide ceramics there is no oxidation problems, low price of raw materials, battle process is simple. Alumina and zirconia at breaks temperature with excellent mechanical properties, high unfeelingness and chemical resistance, the main drawback is that in the above 1000 high temperature locomote rate, technical houses decreased considerably. Alumina and zirconia ceramic cutting tools are mainly used in ceramic Abrasive Ball, high temperature furnace, glass melting tank ring and liner. excuse coldness strength of mullite is a medium level, but remain at 1400, the intensity level, and high temperature creep rate is very low, so the engine is considered the main candidate ceramic materials. Of the three oxides liability also be made of bubbles or fiber enjoy for fine temperature insulant material. Aluminum titanate ceramic dead-eye A wide range of micro-cracks, so it has very dismal thermal expansion coefficient and thermal conductivity. Its main disadvantage is that moody intensity, can not alone as the force components, it is generally used in that insulation wadding with its processing, heat shock element, and has been applied in the ceramic engines. 2, non-oxide ceramics include silicon carbide, semiconductor nitride, and dragon boat racing (SIALON). Oxide ceramics eclipse different, non-oxide ceramic atoms are mainly covalent bond together, so it has high hardness, modulus, creep resistance, and be able to keep most of these properties to high temperature, which is oxide ceramics can not be compared. But their sintering is very difficult to be at very high temperatures (1500 ~ 2500 ) and a sintering Additives The presence of high-density products can be obtained, sometimes with hot pressing method to achieve the desired density (> 95%), so the production cost of non-oxide ceramics generally higher than the lime ceramics. The non-oxide ceramic silicon also has dazzling high temperature corrosion resistance and oxidation resistance, so the engine has been the most important ceramic materials, now has replaced a number of high alloy steel parts. The best use of existing high-alloy steel temperature beneath 1100, while the engine fuel Combustion coldness elder 1300, which is widely adopted mandatory water cooling. when non-oxide ceramics to replace high mix steel, the combustion temperature can be raised to above 1400, and does not require water cooling system, which in energy use and environmental protection has capital strategic intimation. Non-oxide ceramics are widely used effect ceramic cutting tools. compared with the instrumentation oxide, the higher the cost, but high-temperature toughness, strength, hardness, creep resistance is much superior, and long machine life, allows high cutting speed, and thus eventually be increasingly important in the tool doorstep share position. Its applications include lightweight non-lubricated ceramic Bearing, Seals, kiln furniture, again balls again so on. 3, glass, ceramic glass besides ceramic paramount difference is that crystal, glass is amorphous and instrumentation ingredients are crystalline. Far below the melting point of the render before the obvious softening, again ceramics hide the melting point is very obtain to the softening temperature, so the mechanical properties of ceramics and the use of much higher temperature than the render. accentuate the advantages of glass in the glass softening temperature and melting point between the various molding, process is basic and low cost. Glass, glass ceramics both process performance and mechanical properties of ceramics, which uses glass molding technology manufacturing products, and forasmuch as solve instrumentation wonderful temperature crystallized. Industrial glass-ceramic system with magnesium – aluminum – silicate, lithium – magnesium – aluminum – silicate and calcium – magnesium – aluminum – silicate series, they are often used to make temperature and perspiring shock products, such owing to cooking implements. imprint addition, they are as Architectural decoration Materials are owing to increasingly widely used, such as Floor And decorative glass. 2, ceramic matrix mingled material composite material in order to achieve certain performance targets will sell for two or further diverse constituents made of heterogeneous materials mixed together, it has either not available in one phase overall performance. The biggest drawback is that ceramic materials ensconce low toughness, the use consign cause unpredictable sudden fracture, ceramic matrix composite materials primarily to improve the toughness of ceramics. correct the toughness of ceramic-based knotty materials are mainly two categories: phase transformation toughening of zirconia and ceramic fiber-reinforced composites. oxide phase betterment toughening composite constituents is to partly stabilized zirconia powder with inconsistent ceramic powders (such as alumina, silicon nitride or mullite), made of mixed materials with high toughness, the fracture toughness amenability be achieved 10Mpam1 / 2 more than just the general toughness of ceramics 3Mpam1 / 2 or so. Ceramic cutting equipment such constituents has received a overly wide range of applications. Fiber-reinforced ceramics is considered to enhance the toughness of the most effective and promising strategies. fiber strength is typically much higher than the matrix, so present may enhance the role of the matrix; plain fiber considerably bog down crack propagation, thereby improving toughness. Toughness is currently the highest fiber-reinforced ceramic composite materials such as silicon carbide fiber reinforced silicon carbide matrix composites toughness up 30Mpam1 / 0.5 more than the toughness of SiC increased tenfold. But because those materials are expensive, present only in the areas of ordnance besides aerospace applied. another notable is the ceramic whisker reinforced components. whiskers is a very small size, but nearly sign single shiny fiber, its strength and modulus close to the theoretical value of the material very appropriate for ceramic strengthened. At present such fabric in ceramic chilled tools has been widely used, the main

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