Questions and answers
Ceramics
All questions and answers from this set.
Questions: 81
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Question 46
Why the casted objects shrink during drying?
because of water/solvent removal
Question 47
How water is removed from the casted object during casting to non-porous (plastic) moulds?
The water is removed from the casted thanks to rotation of the mould
Question 48
Characterization of tape casting
Tape casting has been used to produce thin layers of ceramics. The Tape Casting process involves the casting the slurry onto a flat moving carrier surface. The slurry usually consists of a ceramic powder with the appropriate additions of solvents plasticisers and binders.
Question 49
Why the thin ceramic foil can be produced from the viscous suspension?
Selection of the suitable composition of the suspension assures its good fl uidity and obtainment of the thin homogenous layers with the uniform structure
Question 50
Which parameter control viscosity of ceramic suspension?
Amount of Solvent
Question 51
Give an example of application of thin ceramic foil in industry
Fuel cells, Structural ceramics, Medical electronics
Question 52
Give the principle of gel casting of ceramic slurries
Gel casting – the process is a method of forming a ceramic powder by in-situ polymerisation. Slurry is mixed with monomer, and then polymerisation begins.
Question 53
Explain the term “ceramic additive manufacturing”
Ceramic component directly from CAD file. Components are produced in successive layers with a laser that polymerizes a paste made of photosensitive resin and ceramic. Time saving, cost effective (without moulds)
Question 54
54. Describe stages (3) of injection moulding of ceramic slurries
• Design of the feedstock (ceramic powder, binder) • Injection forming • Debinding
Question 55
Main components of ceramic slurry for injection moulding
• Main polymer • Plasticizer • Lubricant • Surfactants
Question 56
Describe ceramic components made via injection moulding (examples, application)
• Al2O3; ZrO2 – Nozzles • Si3N4, sialon - Fuel injection valves, parts of shafts, rotors, valves • SiC, ZrO2 Si3N4, sialon - Parts of the fuel pumps,
Question 57
List methods (3) of ceramic powder compaction
Uniaxial, isostatic, vibrational
Question 58
Advantages (3) of powder uniaxial pressing in comparison to other methods of shaping
High yield, Simple, No shrinkage during drying
Question 59
Disadvantages (3) of the powder uniaxial pressing in comparison to other methods of shaping
Shape limitations, Height limitations, Density non-homogeneity
Question 60
List stages (3) of the powder uniaxial pressing
powder --&rt; perforation --&rt; green body