Chapter 13 -1ISSUES TO ADDRESS...•How do we classify ceramics?•What are some applications of ceramics?•How is processing different than for metals?Chapter 13: Applications and Processing of Ceramics
Chapter 13 -2• Properties:--Tmfor glass is moderate, but large for other ceramics.-- Small toughness, ductility; large moduli & creep resist.• Applications:-- High T, wear resistant, novel uses from charge neutrality.• Fabrication-- some glasses can be easily formed-- other ceramics can not be formed or cast.GlassesClay productsRefractoriesAbrasivesCementsAdvanced ceramics-optical -composite reinforce -containers/ household-whiteware-bricks-bricks for high T (furnaces)-sandpaper -cutting -polishing-composites -structuralengine -rotors -valves -bearings-sensorsAdapted from Fig. 13.1 and discussion in Section 13.2-6, Callister 7e.Taxonomy of Ceramics
Chapter 13 -3•Need a material to use in high temperature furnaces.• Consider the Silica (SiO2) - Alumina (Al2O3) system.•Phase diagram shows:mullite, alumina, and crystobaliteas candidate refractories.Adapted from Fig. 12.27, Callister 7e.(Fig. 12.27 is adapted from F.J. Klug and R.H. Doremus, "Alumina Silica Phase Diagram in the Mullite Region", J. American Ceramic Society70(10), p. 758, 1987.)Application: RefractoriesComposition (wt% alumina)T(°C)14001600180020002200204060801000alumina+ mullitemullite + LmulliteLiquid(L)mullite+ crystobalitecrystobalite+ Lalumina + L3Al2O3-2SiO2
Chapter 13 -4tensile forceAoAddiedie•Die blanks:-- Need wear resistant properties!•Die surface:-- 4 μm polycrystalline diamondparticles that are sintered onto acemented tungsten carbidesubstrate.-- polycrystalline diamond helps controlfracture and gives uniform hardnessin all directions.Courtesy Martin Deakins, GE Superabrasives, Worthington, OH. Used with permission.Adapted from Fig. 11.8 (d), Callister 7e. Courtesy Martin Deakins, GE Superabrasives, Worthington, OH. Used with permission.Application: Die Blanks
Chapter 13 -5• Tools:-- for grinding glass, tungsten,carbide, ceramics-- for cutting Si wafers-- for oil drillingbladesoil drill bits• Solutions:coated singlecrystal diamondspolycrystallinediamonds in a resinmatrix.Photos courtesy Martin Deakins,GE Superabrasives, Worthington,OH. Used with permission.Application: Cutting Tools-- manufactured single crystalor polycrystalline diamondsin a metal or resin matrix.-- optional coatings (e.g., Ti to helpdiamonds bond to a Co matrixvia alloying)-- polycrystalline diamondsresharpen by microfracturingalong crystalline planes.
Chapter 13 -6• Example:Oxygen sensor ZrO2• Principle:Make diffusion of ionsfast for rapid response.Application: SensorsACa2+impurityremoves a Zr4+