topic 1.7: Smart and modern materials

Question 1

Thermo-ceramics

Answer 1

Features:
Metal powder is placed in a mould or die under high pressure. The high pressure forces the particles to bond.

Thermo-ceramics are very hard and stable at high temperatures (up to 100*C)

Uses:
Turbine blades in jet engines, turbo charges in racing cars, tips on cutting tools such as drill bits, high end skateboard bearings, metal cutting tooling.

Question 2

Shape memory alloys (SMA)

Answer 2

Features:
Changes shape in response to a change in temperature or electrical input.

for example; nitinol wire in dental braces changes length in response to a change in temperature.

Uses:
Dental braces, self closing windows, aeroplane wing flaps, bioengineering such as stents, bone plates and screws.

Question 3

Reactive glass

Answer 3

Features:
Glass reacts to a change in temperature by changing the tint.

When the glass gets hot the glass darkens to block the heat from entering through the glass.

Uses:
Apartment or office block, windows, conservatories, glass roofing windows.

Question 4

Liquid crystal displays (LCD)

Answer 4

Features:
Liquid crystals change colour when an electric voltage is applied. the cell turns from light to dark.

Uses:
Digital clocks and watches, computer screens, car audio displays.

Question 5

Photochromic material

Answer 5

Features:
Changes colour with light intensity.

Uses:
Welding goggles, reactive spectacle lenses, security markers that show under UV light, car rear view mirror

Question 6

Thermo-chromic material

Answer 6

Features:
changes colour in response to temperature change.

Uses:
room thermometers, medical thermometers for children, bath water thermometers, colour change mugs and kettles, food packaging to indicate food is hot to eat or cool for drinks, baby feeding spoons, battery charge indicator strips.

Question 7

Quantum tunnelling composites

Answer 7

Features:
Insulating rubber containing tiny metal particles.

The material is pressure or force sensing. When there is change in the applied pressure or force, the material changes from electrical insulator to conductor

Uses:
Touch screen technology smart phone buttons, pressure sensors, speed controllers in power tools,