Ceramics Flashcards
What is the four type of castings
Isostatic
Unidirectional
Slip- fill a void with slurry
Hydro plastic
What can pores be used for
Makes it lighter
Conducts less
What are the process of ceramic
raw material
Blending and mixing
Drying - removes water both types which moves everything closer and makes pores
Sintering - preheated which burned off another lubes and binders into sintering which is in vacuum at high heat which causes diffusion and then cooled slowly
Finishing
bonding in ceramics
ionic- donation of electrons
and covalent- sharing of electrons
general characteristics of ceramics
very brittle
strong primary bonds also give rise to high melting point
poor conductors of electricity
lower fracture toughness than metals
additives in to ceramics
binders-
improve the mechanical strength of green ceramic bodies
lube-
decrease friction in pressing process reduces cracking through giving uniform stresses
wetting agent-
reduce surface tension of the liquids
plasticizers-
soften the binders
deflocculant- reduces viscosity
four types of water removed in drying
water of suspension
inter particle water
pore water
absorbed water
in sintering what happens in ceramics as they will not melt
➢ Homogenization does not take place during a molten
process so the mechanism by which it must take
place is solid-state diffusion (Sintering).
when the water is removed, how do the pores get reduced
the particles are fused together which removed the pores by sintering by using heat and sometimes pressure.
what are defects in ceramics
pores and grain boundaries and particle surfaces can act as defects
what are failure of ceramics
As a group ceramics are generally very brittle materials, particularly at
low temperatures. This problem is heightened by the presence of
flaws such as cracks, porosity or inclusions, et
