Ch141.91(MSE101) Project


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Ch141.91(MSE101) Project

  1. 1. Ceramics<br />Types and Applications<br />
  2. 2. CERAMICS<br />Keramikos (Greek - burnt stuff)<br />Properties are achieved normally through a high-temperature heat treatment (firing)<br />Materials composed of at least two elements<br />Primary components:<br />Silicates<br />Carbons<br />
  3. 3. COMMONLY FABRICATED CERAMICS<br />Glass<br />Clay<br />Refractories<br />Cement<br />Abrasives<br />Advanced Ceramics<br />
  5. 5. CLAY<br />
  6. 6. widely used ceramic raw material<br />inexpensive ingredient<br />found naturally in great abundance<br />used as mined without any upgrading of quality<br />CLAY<br />
  7. 7. <ul><li>forms a plastic mass that is very amenable to shaping when mixed with water in proper proportions
  8. 8. dried, and then fired at an elevated temperature to improve its mechanical strength</li></ul>CLAY<br />
  10. 10. STRUCTURAL CLAY<br />Specifications for raw materials used in most structural clay products:<br />Plastic enough for shaping<br />Dry without excessive cracking and warping<br />Have low and wide vitrification range<br />Low carbonate content<br />Have a spread in particle size<br />Contain non-clay constituents<br />
  11. 11. STRUCTURAL CLAY<br />include building bricks, tiles, and sewer pipes<br />used in applications in which structural integrity is important (resistant to mechanical and chemical stress)<br />proportions above are often found directly in shale deposits, so that blending is often not necessary.<br />
  12. 12. STRUCTURAL CLAY<br />made from 35 -55% clays or argillaceous (clayey) shales, 25-45% quartz, and 25-55% feldspar<br />clay portion acts as a former, providing shaping ability<br />quartz (silica) serves as a filler, providing strength to the formed object<br />feldspar serves as a fluxing agent, lowering the melting temperatures of the clay and quartz during firing<br />
  13. 13. STRUCTURAL CLAY<br />properties determined by particle size, firing temperature, and ultimate microstructure<br />coarser filler particles are used, and lower firing temperatures are employed—typically in the range of 1,050° to 1,100° C <br />Resulting microstructure: large secondary particles in a matrix of fine-grained mullite and glass—all containing a substantial volume of large pores.<br />
  14. 14. STRUCTURAL CLAY<br />Because of the presence of large and small particles in their microstructures, fired clay products have relatively high compressive strengths – good for structural applications<br />if underfired: low strength and poor resistance to frost and freezing, due to small pores in the clay regions<br />If overfired: ware has too much glass; it is strong but brittle and is susceptible to failure under mechanical and thermal stress. <br />
  15. 15. WHITEWARES<br />
  16. 16. STRUCTURAL CLAY<br />become white after the high-temperature firing<br />porcelain, pottery, tableware, china, and plumbing fixtures<br />many contain nonplastic ingredients, <br />influences the drying and firing processes and the characteristics of the finished piece<br />
  17. 17. STRUCTURAL CLAY<br />mostly composed of a mixture of kaolin, ball clay and ground non-clay materials including feldspar, quartz, talc and others<br />higher alumina materials such as kyanite and specially treated kaolins are being incorporated in some of the whitewareproducts <br />
  18. 18. CEMENT<br />
  19. 19. CEMENTS<br />Plaster of Paris, concrete, lime<br />Used in binding materials (i.e. sand and gravel to form concrete) or surfaces, or to coat against chemical attack<br />
  20. 20. CEMENTS<br />hardens by the evaporation of the plasticizing liquid (i.e. water, alcohol, or oil) by internal chemical change, by hydration, or by the growth of interlacing sets of crystals, or by their reaction with the oxygen or carbon dioxide in the atmosphere.<br />Microscopic Image of Cement<br />
  21. 21. CEMENTS<br />Processed according to sequence: calcination, grinding, addition of gypsum (retards/slows cement setting process)<br />Calcination – grinding and intimately mixing clay and lime-bearing minerals in proper proportions, heating to 1400oC in a rotary kiln<br />
  22. 22. COMPOSITION<br />
  23. 23. PROPERTIES<br />Powder form is mixed with water to form a paste that may be molded into any size and shape<br />bond develops at room temperature (unlike refractory bricks, or clay)<br />may act as a bonding phase that chemically binds particulate aggregates into a single cohesive structure<br />May have properties of refractories<br />
  24. 24. TYPES<br />1. Portland Cement <br />obtained by pulverizing clinker consisting of hydraulic calcium silicates, to which no additions (except for a little H2O or untreated CaSO4) have been made before calcinations<br />typically used in construction<br />
  25. 25. TYPES<br />2. Pozzolan Cement <br />strong slow-hardening type of cement from finely divided siliceous and aluminous materials that react chemically with slaked lime at ordinary temperature in the presence of moisture<br />3. Controlled Cement <br />cement that prevents shrinking and cracking upon setting<br />
  26. 26. TYPES<br />4. High alumina cement<br />characterized by a very rapid rate of strength development and superior resistance to sea water and sulfate-bearing water.<br />5. Special or Corrosion Resisting cement <br />used in large quantities for the fabrication of corrosion-proof linings for chemical equipment<br />
  27. 27. ABRASIVE CERAMICS<br />
  28. 28. ABRASIVE CERAMICS<br />silicon carbide, tungsten carbide (WC), aluminum oxide (or corundum), and silica sand.<br />Diamonds, both natural and synthetic (relatively expensive)<br />
  29. 29. ABRASIVE CERAMICS<br />substance used to wear, grind, polish an or cut away other material<br />bonded to a wheel by means of glassy ceramic or an organic resin<br />commonly used in household cleaning products and manufacturing processes<br />
  30. 30. STRUCTURE<br />Principle Construction of Coated Abrasives (cloth backing)<br />The surface structure should contain some porosity; a continual flow of air currents or liquid coolants within the pores that surround the refractory grains prevents excessive heating.<br />
  31. 31. STRUCTURE<br />Al2O3 abrasive grains<br />Bonding phase<br />porosity<br />Photomicrograph of an aluminum oxide bonded ceramic abrasive<br />
  32. 32. PROPERTIES<br />The size, shape, and hardness of a substance’s particles determine its characteristics as an abrasive.<br />Coarse, larger grains normally remove material faster than smaller grains.<br />Wear Resistant<br />High degree of toughness<br />Refractoriness<br />withstand high temperatures without melting or decomposing<br />
  33. 33. TYPES<br />1. Coated Abrasives<br />Abrasive powder is coated on some type of paper or cloth material<br />Ex. Sandpaper<br />
  34. 34. TYPES<br />2. Loose Abrasive Grains<br />Employed in grinding, lapping, and polishing wheels<br />Delivered in some type of oil- or water-based vehicle.<br />
  35. 35. Refractories<br />
  36. 36. PROPERTIES<br />capacity to withstand high temperatures without melting or decomposing<br />capacity to remain unreactive and inert when exposed to severe environments.<br />ability to provide thermal insulation<br />- performance depends on composition<br />- bulk densities range from 2.1 to 3.3 g/cm^3.<br />Aluminum melting furnace<br />
  37. 37. PROPERTIES<br />Porosity<br />one microstructural variable that must be controlled to produce a suitable refractory brick. <br />an decrease in porosity will increase strength, load-bearing capacity, and resistance to attack by corrosive materials.<br />thermal insulation characteristics and resistance to thermal shock are diminished as porosity is decreased. <br />
  38. 38. COMPOSITION<br />
  39. 39. TYPES<br />Fireclay<br />primary ingredients are high-purity fireclays, alumina and silica mixtures usually containing between 25 and 45 wt% alumina.<br />mechanical integrity will not be compromised with the presence of a small amount of liquid phase.<br />upgrading the alumina content will increase the maximum service temperature.<br />
  40. 40. TYPES<br />Silica<br />acid refractories<br />prime ingredient is silica<br />has a high-temperature load-bearing capacity.<br />used in arched roofs of steel and glass-making furnaces<br />readily attacked by slags composed of a high proportion of CaO and/or MgO<br />
  41. 41. TYPES<br />Basic<br />rich in periclase or MgO, may also contain calcium, chromium, and iron compounds.<br />presence of silica is deleterious to their high-temperature performance<br />resistant to attack by slags containing high concentrations of MgO and CaO<br />has extensive applications in some steel-making open hearth furnaces<br />Lime Klin<br />
  42. 42. SPECIAL REFRACTORIES<br />Examples:<br />high-purity oxide materials<br />alumina, silica, magnesia, beryllia(BeO), zirconia (ZrO2), and mullite (3Al2O3-2SiO2).<br />Carbide compounds<br />Silicon Carbide (SiC)<br />used for electrical resistance heating elements (crucible material) and internal surface components.<br />carbon and graphite <br />very refractory but limited in application due to their susceptibility to oxidation at temperatures > 800oC. <br />expensive<br />
  43. 43. APPLICATIONS<br />High-duty fireclay brick<br />linings for cement and lime klins, blast furnaces and incinerators<br />High-alumina brick<br />boiler furnaces, spent-acid regenerating furnaces, phosphate furnaces <br />
  44. 44. APPLICATIONS<br />Superduty fireclay bricks<br />linings for aluminum-melting surfaces, rotary kilns, blast furnaces, and hot-metal transfer ladles<br />Silica brick<br />chemical reactor linings, glass tank parts, coke ovens <br />Rotary Klin<br />
  45. 45. APPLICATIONS<br /> Magnesite brick<br />basic-oxygen-process furnace linings for steelmaking<br />Zircon brick<br />glass-tank bottom paving and continuous-casting nozzles<br />Continuous-casting Nozzles<br />
  46. 46. GLASS<br />
  47. 47. GLASS<br />Amorphous (literally, without form - noncrystalline) silicates containing other oxides (i.e. CaO, Na2O, K2O, Al2O3)<br />Typical soda-lime glass consists of approximately 70 wt% SiO2, balance maintained by Na2O (soda) and CaO (lime).<br />2-D schemes of a) crystalline silicon dioxide; b) amorphous silicon dioxide.<br />
  48. 48. PROPERTIES<br />Optically transparent<br />Relatively easy to fabricate<br />Ex. Containers, windows, lenses<br />
  49. 49. COMMERCIAL GLASSES<br />
  50. 50. T-V Dependence of Glass<br />Crystalline solids – nucleation occurs at specific temperature<br />Amorphous solids (glass) – viscosity increases as temperature decreases<br />Temperature depends on the composition (i.e. 96% silica – 1550oC, 108Pa-s).<br />
  51. 51. T-V Dependence of Glass<br />
  52. 52. GLASS-CERAMICS<br />A crystallized form of inorganic glasses<br />Done through a high-temperature heat treatment called devitrification (crystallization)<br />A nucleating agent (usually TiO2) is added to induce crystallization or devitrification process<br />Aluminum silicate glass-ceramics<br />
  53. 53. PROPERTIES<br />Fine-grained polycrystalline material<br />As a result: high mechanical strengths<br />SEM micrograph of a glass-ceramic<br />
  54. 54. PROPERTIES<br />Low coefficient of thermal expansion,<br />Good dielectric properties<br />Good biological compatibility<br />Optical properties (opacity) can be adjusted<br />Excellent insulators, serving as substrates for circuit boards<br />
  55. 55. EXAMPLES<br />Left: Glass-ceramic china pot; Above: Glass-ceramic cooktop<br />
  56. 56. ADVANCED CERAMICS<br />
  57. 57. ADVANCED CERAMICS<br />Also called “special,” “technical” and “engineering” ceramics<br />Exhibit superior mechanical properties, corrosion/oxidation resistance, or electrical, optical, and/or magnetic properties<br />Aforementioned properties are usually paired with other properties unique to ceramics<br />Developed only in the past 100 years<br />
  58. 58. Advanced vs. Traditional Ceramics<br />
  59. 59. Advanced vs. Traditional Ceramics<br />
  60. 60. Advanced vs. Traditional Ceramics<br />
  61. 61. EXAMPLES<br />Zirconia (ZrO2)<br />Silicon Nitride (Si3N4)<br />Silicon Carbide (SiC)<br />Boron Carbide (B4C)<br />Alumina (Al2O3)<br />Graphite<br />Diamond<br />
  62. 62. TYPES<br />Structural Ceramics<br />Made of components such as Si3N4, SiC, ZrO2, B4C and Al2O3<br />Have high hardness, low density, high-temperature mechanical strength, creep resistance, corrosion resistance, chemical inertness<br />Used in cutting tools, wear components, heat exchangers, and engine parts<br />
  63. 63. TYPES<br />Electronic Ceramics<br />Made ofBaTiO3, ZnO, lead zirconatetitanate [Pb(ZrxTi1−x)O3], AlN, and HTSCs<br />Applications are capacitor dielectrics, varistors, microelectromechanical systems (MEMS), substrates, and packages for integrated circuits<br />Coatings and Films<br />modify surface properties of a material<br />may be for economic reasons(i.e. diamond coating)<br />in some cases, may improve material performance<br />
  64. 64. TYPES<br />Bioceramics<br />Used in the human body<br />Response varies from<br />Nearly inert bioceramics: include Al2O3and ZrO2<br />Bioactive ceramics: include hydroxyapatiteand some special glass and glass–ceramic formulations.<br />Resorbablebioceramics: Tricalciumphosphate (dissolves in the body)<br />
  65. 65. APPLICATIONS<br />Microelectromechanical Systems (MEMS)<br />Miniature “smart” systems<br />Made up of many mechanical devices integrated with a large number of electrical elements on a substrate of silicon<br />Can detect and react to changes in its environment using its microsensors, microactuators and mircoelectric components<br />
  66. 66. APPLICATIONS<br />Studies are being made on the use of ceramics<br />Limitations of silicon in MEMS<br />low fracture toughness<br />relatively low softening temperature<br />highly active to the presence of water and oxygen<br />Ceramic materials are being considered because they are tougher, more refractory and more inert <br />amorphous silicon carbonitrides (silicon carbide–silicon nitride alloys) made from metal organic precursors are currently being studied<br />
  67. 67. APPLICATIONS<br />Accelerometer in cars used in the deployment of air-bag systems<br />smaller, lighter, more reliable and less expensive than conventional air-bags system<br />Other possible MEMS application are:<br />electronic displays and data storage units<br />energy conversion devices<br />chemical detectors (for hazardous chemical and biological agents, and drug screening)<br />microsystemsfor DNA amplification and identification<br />
  68. 68. APPLICATIONS<br />Optical Fibers<br />Critical component in our modern optical communications systems<br />signal transmission is photonic, instead of electronic: uses electromagnetic radiation<br />improved speed of transmission, information density, and transmission distance<br />reduction in error rate<br />no electromagnetic interference<br />
  69. 69. APPLICATIONS<br />Ceramic Ball Bearings<br />A bearing consists of balls and races that are in contact with and rub against one another when in use<br />traditionally made of bearing steels that are very hard, extremely corrosion resistant and may be polished to a very smooth surface<br />Silicon nitride (Si3N4) balls have begun replacing steel balls in a number of applications<br />Hybrid bearing<br />
  70. 70. APPLICATIONS<br />Hybrid Bearings<br />Races are still made of steel<br />Better tensile strength than silicon nitride<br />Balls are made of silicon nitride<br />Lower density: hybrid bearing is lighter enabling higher operation speeds<br />Higher modulus of elasticity: more rigid and less prone to deformations when in use so there is a reduction in noise and vibration levels<br />
  71. 71. APPLICATIONS<br />Inline skates<br />Bicycles<br />Electric motors<br />Machine tool spindles<br />Precision medical hand tools (e.g., high-speed dental drills and surgical saws)<br />Textile, food processing<br />Chemical equipment<br />
  72. 72. Advanced Ceramics: Breakthrough<br />
  73. 73. Piezoelectric Ceramics<br />Exhibit the unusual phenomenon of piezoelectricity<br />electric polarization (i.e., an electric field or voltage) is induced in the ceramic crystal when a mechanical strain is imposed on it and vice-versa<br />Piezoelectric ceramics include BaTiO3, PbTiO3, lead zirconate–titanate (PZT) [Pb(Zr,Ti)O3], potassium niobate (KNbO3)<br />
  74. 74. Piezoelectric Effect<br />
  75. 75. Applications of Piezoelectric Ceramics<br />Gas lighter/igniter<br />Sonar (in submarines)<br />Medical ultrasonic applications<br />Accelerometers<br />Transformers<br />Ink-jet/dot-matrix printers<br />Laser beam scanners<br />Automatic camera focusing systems and camera shutters<br />Sensors for burglar alarm<br />
  76. 76. Sources<br />Bayquen, Ph.D., Cecilia V.; University of Sto. Tomas. Industrial Chemical Processes Book 2. Manila, 2007.<br />Callister Jr., William D. Materials Science and Engineering An Introduction. Quebecor: Quebecor Versailles, 2007.<br />Carter, C. Barry, and M. Grant Norton. Ceramic materials science and engineering. New York: Springer, 2007.<br />Heimann, Robert. Classic and advanced ceramics: From fundamentals to applications. Weinheim: WILEY-VCH, 2010.<br />Kingery, W. D., H. K. Bowen, and D. R. Uhlmann. Introduction to Ceramics. John Wiley & Sons., 1976.<br />Microsoft® Encarta® 2007 [DVD]. Cement. Redmond, WA, 2006.<br /><br />
  77. 77. Image Sources<br />Advanced Ceramics<br /><br /><br /><br /><br /><br /><br /><br /><br />
  78. 78. Image Sources<br />Glass<br /><br /><br /><br /><br /><br /><br />
  79. 79. Image Sources<br />Refractories<br /><br /><br /><br /><br /><br /><br />Abrasives<br /> <br /> <br /><br />
  80. 80. Image Sources<br />Clay<br /><br /><br /><br /><br />Cement<br /><br /><br /> <br />