Smart And Modern Materials Flashcards
Thermo ceramics
Produced by combining ceramic and metallic powders by sintering
These powders are then heated and then placed in a die and subjected to a very high pressure until the particles bind with each other.
Extremely hard due to internal structure
Very stable at very high temperatures
» therefore used in turbine blades in jet engines or turbo chargers of racing cars (need for stability and strength and high temperatures)
A lot lighter than metals
Can withstand higher temperatures than metals
Brittle
Hard to machine
Expensive
Shape memory alloys
If a part it component made from SMA is bent out of shape it is heated above a certain temperature it will return to it’s original shape - acts like a switch
Can be used in spectacle frames - if bent placed in hot water
Triggers to start sprinklers in fire alarm systems
Controllers for hot water valves in showers or coffee machines
Reactive glass
Smart glass
Requires a power source/external stimulus to enable it to operate
Impregnated with SILVER HALIDE particles
Reacts to light as electrical current flows though it and the sh particles
- Possibility of adjusting - U can achieve different levels or shades of darkness
- very expensive
Used in high rise buildings/ Glass panels
Replaces curtains with switch of a button
LCD - Liquid crystal displays
Liquid crystals are organic carbon based compounds
LCDs can have a pattern of conducting electrodes to display numbers via 7 segment display
Certain voltage applied to each segment which then goes dark in relation to silver background, caused by molecular rearrangement within the liquid Crystal
Eg digital watch
Small amount of power required - ideal for portable devices eg mobile phones - extending battery life
Photo chromic materials
Change colour according to different lighting conditions such as sunlight or uv light
Eg: photo chromic paints - change colour according to light conditions
Immediate and dramatic change
Reversible
Used in:
Security markers
Ur light warning sensors
Thermo chromic materials
Change colour as temperature changes
At specific temperatures, liquid crystals re orientate to produce an apparent change of colour
Used in thermometers
Side of batteries
Food pacakaging
Quantum tunnelling composites
- type of polymer
- product as well as a material
In relaxed state - a near perfect electrical insulator
(Stretched, compressed or twisted)
When stress applied - becomes an electrical conductor
Applications:
- toys n games
- sport
- medicine
- Clothing
- Tools
- robotics
Smart materials - additional notes
Refers to a group of materials whose properties and characteristics change when presented with an external stimulus such as heat, light, sound, vibration or electrical current.
When this external stimulus is removed the product returns to its original form and shape
