Graphite -> Glass (I) Flashcards
physical appearance of GRAPHITE
one of the two allotropes of carbon, it has a black to dark gray color with a dull sheen, can be mined in its natural form.
microstructure of GRAPHITE
very strong crystalline layers stacked on top of each other with poor and weak bonds between these layers
What everyday object uses GRAPHITE (where it is often referred to as lead)?
pencils
metallic traits of GRAPHITE
can conduct electricity, ability to be machined (cut) using the same tools used for metals
non-metallic trait of GRAPHITE
it does not melt under atmospheric pressure (makes it excellent for making crucibles or as casting molds for refractory metal alloys), high natural LUBRICITY (it is slippery)
CERAMICS
consist of mineral-like ingredients, either as mixtures or in a pure form.
PURE CERAMICS
created as lumps of raw product in a chemical plant
COMMINUTION
process of crushing the lumps into powder in a BALL MILL.
BALL MILL
a cylindrical drum that is lined with wear-resistant panels or bricks (Burrstone, Silica, or Alumina) and filled with ceramic balls (Zirconium Silicate). The lumps are turned into powder.
What is mixed with the ceramic powder to create the desired thickness?
ceramic powder + water + binder(s)
SLIP (in terms of ceramics)
larger amounts of water will create a runny and pourable consistency, allows the adoption of processes analogous to metal casting, but without the need for heat
limiting the amount of water will produce a thick pliable plastic form suitable for…
MOLDING
SLIP CASTING
same as SLUSH CASTING, but for ceramics instead of metals; slip is poured into a split mold and poured out when the desired thickness has solidified
CERAMIC SPIN CASTING
similar to CENTRIFUGAL SPIN CASTING, but with ceramics instead of metals
MOLDING
when shaping the pliable plastic MOLDING form of the moist ceramic blend, the methods are similar to FORGING and EXTRUSION of metals
CERAMIC PRESSING
similar to CLOSED/IMPRESSIONS DIE FORGING
CERAMIC EXTRUSION
pushes the material through the die cavity and the two die halves are brought together; a SCREW CONVEYER provides the driving force
JIGGERING
the industrial equivalent of the manual potter’s wheel to mass produce circular forms; parts: plaster mold, clay slug, bat, bat former, jigger tool
JIGGER TOOL
equivalent to potter’s hands; sweeps around the bat to create the final shape
DRYING in terms of CERAMICS
the ceramic shape needs to be dried because any moisture can turn into steam and cause cracks in the FIRING STAGE
GREENWARE
the resulting ceramic after the drying process, in a solid but fragile GREEN STATE, strong enough for light handling
GREEN MACHINING
process of cutting GREENWARE
KILN
a special oven that the final shape GREENWARE is placed into, the ceramic undergoes a chemical change that results in cross-linking and shrinking
BISQUEWARE
the GREENWARE goes into the KILN and it is called BISQUEWARE when it comes out
What are the advantages and disadvantages of BISQEWARE?
ADV- hard and durable
DISADV- porous and susceptible to shattering from impacts or thermal shock
HARD MACHINING
a technique used to machine BISQUEWARE
DISADVANTAGE of HARD MACHINING
it requires abrasive cutting techniques; the ceramic is “notch sensitive” and care is needed to avoid sharp corners where cracks can start
GLAZING
method of addressing the porosity of BISQUEWARE by applying a surface coating of runny SLIP
GLAZEWARE
the coated BISQUEWARE is put in the KILN again and comes out as GLAZEWARE
EXAMPLES of GLAZED products
most tableware ceramics, bathroom tiles, turbine blades
GLASS
composed mostly of SILICA which exists in a crystalline form known as QUARTZ, and an amorphous state called FUSED SILICA
FUSED SILICA
has a disorganized microstructure and possesses the transparent appearance of GLASS
SODA LIME GLASS
contains sodium oxide (soda) and calcium oxide (lime)
LEAD/FLINT GLASS
SILICA and LEAD OXIDE; known for its sparkle and clarity, while being able to block GAMMA and X-RAYS
CROWN GLASS
POTASSIUM OXIDE creates this glass
BOROSILICATE GLASS
BORON OXIDE results in this glass; known as PYREX, with superior thermal-shock resitance
GORILLA GLASS
flexible corning glass widely used for smartphone and tablet screen protectors
GLASS in the form of PLATE or SHEET
widely used in architectural applications, formed using rollers
FLOAT GLASS
process of making very flat and smooth glass for window panes, the glass is supported by liquid tin during this process
Why is LIQUID TIN used in the FLOAT GLASS process?
- non-toxic
- more dense than glass
- lower MP than glass temp
- higher BP than glass temp
- non-reactive with glass
- non-wetting
GLASS BLOWING
a GOB of molten glass is placed on the end of a long tube. a craftsman uses their lungs to force air into the center of the GOB, creating the glass container shape
AUTOMATED GLASS BLOWING
the GOB is formed into a crude container called a PARISON using a pressing method. the PARISON is then transferred to a split mold of the final desired shape and reheated
GLASS FIBER
long lengths of straight fiber with consistent diameters can be produced by BUSHING
BUSHING
allowing molten glass to pour through a series of holes
INSULATION BATTS
short curly fibers are preferred bc they don’t pack together very well and leave a majority of airspace
CELLULOSE
was used in attic insulation before GLASS FIBER BATTS, basically just old newspapers
DISADVANTAGES of CELLULOSE
- burns
- absorbs moisture
- attracts critters
- compacts over time
- inferior R-value
FLOOD LAMP - SCREW CONDUCTOR
brass sheet metal is generally used; it is BLANKED, DEEP DRAWN, and then BULGED
FLOOD LAMP - LENS
the lens is PRESSED glass
GLASS PRESSING
similar to ceramic pressing, but the glass GOB is pliable bc of heat instead of moisture
FLOOD LAMP - REFLECTOR
needs to be reflective and PARABOLIC in shape; made with GLASS CENTRIFUGAL CASTING
ADV of CENTRIFUGAL CASTING
any liquid placed into a container and spun will naturally form a parabolic shape
The Achilles Heel of Graphite
Brittleness
True/False: Graphite maintain its slipperiness in space?
True because it is not dependent on oxidation or external lubricants
a specialized application for solid graphite in space vehicles.
docking latch bushings
