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12
CH1012
CERAMICS IV
• Ceramics are
brittle. This poses problems for
manufacturing & use. eg. high-Tc wires.
• Under stress a microfine defect
develops
this widens rapidly until the material cracks.
this widens rapidly until the material cracks.
• What is required are defect-free ceramics or defect-tolerant structures.
• Sintering of uniform ceramic powders at high
T coalesces the particles without
melting creating defect-free structures.
• Organoceramics - created by sintering very small, uniform oxide particles coated with organic polymers, defect-free.
• Ceramics embedded
with ZrO2 are defect-
tolerant as the ZrO2 can expand up to 5%.
tolerant as the ZrO2 can expand up to 5%.
