What are the different classifications of ceramics?
- Glasses (glass/glass-ceramics)
- Clay products (structural/whiteware)
- Refractories (clay/nonclay)
- Abrasives
- Cements
- Ceramic biomaterials
- Carbons (diamond/graphite/fibers)
- Advanced ceramics
What are some applications of glasses?
- Optical
- Composite/reinforcement
- Containers/household
What are some applications of clay products?
- Structural
- Whiteware
What are the applications of refractories?
- Bricks for high temperature furnaces
What are some applications of abrasives?
- Sandpaper
- Cutting
- Polishing
What are some applications of cements?
- Composites
- Structural
What are the applications of ceramic biomaterials?
- Implants
What are some applications of carbons?
- Composites
- Abrasives
What are some applications of advanced ceramics?
- Engine rotors, valves, bearings
- Sensors
Why are ceramics used in die blanks?
- They are used for their wear-resistant properties
- Polycrystalline diamond particles are sintered onto a cemented tungsten carbide substrate
- The diamond gives uniform/isotropic hardness
What tools are ceramics used in?
- To grind glass, tungsten carbide, and other ceramics
- For cutting silicon wafers
- For oil drilling
What is the structure of a ceramic cutting tool?
- Manufactured single crystal or polycrystalline diamonds in a metal or resin matrix
- Polycrystalline diamonds resharpen by microfracturing along cleavage planes
How are ceramics used in sensors?
Ceramic sensors convert physical inputs into electrical outputs. An example of this is ZrO2 as an oxygen sensor, where the diffusion of oxygen through the sensor creates a voltage difference.
What are refractories?
A metal or ceramic that may be exposed to extremely high temperatures without deteriorating rapidly or without melting.
How does porosity affect refractory bricks?
As porosity increases, the strength and chemical resistivity decreases, but thermal insulation increases.
What are the advantages of using advanced ceramics in engines?
- Can operate at high temperatures
- Low friction (high efficiency)
- Operate without a cooling system
- Lower weights than metal counterparts
What are the disadvantages of using advanced ceramics in engines?
- Ceramics are brittle
- Difficult to remove internal voids that weaken structure
- Ceramic parts are difficult to form and machine
How are advanced ceramics used in armor?
- Used to form facing plates and backing sheets
- Facing plates are hard and brittle and fracture high velocity projectiles
- Backing sheets are soft and ductile and deform, absorbing energy
What are the three types of nanocarbons?
- Fullerenes
- Carbon nanotubes
- Graphene
What are fullerenes?
Spherical clusters of 60 carbon atoms.
What are carbon nanotubes?
A sheet of graphite rolled into a tube and each end is capped with fullerene hemispheres.
What is graphene?
A single atomic layer of graphite composed of hexagonally bonded carbon atoms.
What are the three types of ceramic fabrication techniques?
- Glass forming
- Particulate forming
- Cementation
What are the four types of glass forming?
- Pressing (gob into parison mold -> pressed)
- Blowing (mold around suspended parison -> blown)
- Fiber Drawing (molten glass pulled into fibers)
- Sheet forming (sheets formed on pool of molten tin)
