1. AS D&T Modern Materials and Products
Thermo- Ceramics
Tinted Glass
Photochromic Glass
Solar Panels
Liquid Crystal Displays
Electroluminescent Lighting
CDL May 2015

2. Thermo- Ceramics Extremely hard materials
Extremely hard materials
Very stable shape at high temperatures
Expensive
Uses: jet engine turbine blades, car brake discs, spacecraft heat protection
Made by a process called sintering using powdered metals
CDL May 2015

3. Sintering
A process used to make new materials by compressing heated powders of metal and ceramics
The particles are not chemically joined like in alloys, but simply stuck together under pressure
Sintered metals have tiny spaces between the particles, which can absorb oil to make bearings that need no maintenance
CDL May 2015

4. Sintering process
CDL May 2015

5. Tinted Glass
Tinted glass is simply glass that has been given a tint, or colour
Normally used to provide shade and protection from bright light
Examples include welding goggles, sunglasses and tinted car windows
The tint is permanent and cannot be reversed
CDL May 2015

6. Tinted Glass example
CDL May 2015

7. Photochromic Glass Similar to tinted glass, but the tint is reversible
Glass automatically darkens when exposed to ultraviolet light
Reverts to clear glass when the light is reduced
Works by mixing tiny particles of Silver Halide into the glass
Silver halide reacts to light and is used in photographic paper (permanent change)
In photochromic glass the reaction is reversible
CDL May 2015

8. Reactive glass
Unlike Photochromic glass, reactive glass relies on an external stimulus to make them go dark
Examples include welding masks and privacy windows
CDL May 2015

9. Solar Panels Originally developed for space exploration
Now becoming viable on earth as an alternative to burning fossil fuels
Solar panels contain Photovoltaic, or Solar cells
Photovoltaic cells are made from layers of silicon; the sun cause an imbalance of electrons between the layers, causing a flow of electricity
The voltages produced are small and the panels require a lot of sunlight to work efficiently
Government subsidies have recently encouraged more householders in the UK to install the panels
CDL May 2015

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12. Liquid Crystal Displays
Made from organic, carbon based compounds
Work by passing an electric current across the liquid crystal, which causes the crystals to align and block light from passing through
Use very small amounts of electricity
LCD TV’s have colour LCD displays, but the picture is not as good as some old cathode ray TV’s, and the viewing angle is not as good
LED TV’s are similar to LCD, but give a better picture and allow the TV to be thinner
CDL May 2015

13. Electroluminescent Lighting
EL lighting are made of an organic phosphor sandwiched between two electrodes
The phosphor emits radiation in the form of visible light
Extremely low power consumption
Used in wristwatches and in advertising
Very thin sheets can be made, which are waterproof so they are good for bill boards and the sides of bus shelters
They have a limited life span
CDL May 2015

14. Shape Memory Alloys
Nitinol (Nickel Titanium Alloy) is the best known SMA
Distorted SMA’s change back to their original shape when heated to an exact temperature
The transition temperature is about 650c for Nitinol
Heating can be by passing an electric current through the wire, or by heating directly
This process can be repeated indefinitely
CDL May 2015

15. Photochromic paint
Photochromic paint contains pigments that change colour according to light conditions
When the light it removed, the paint reverts back to its original colour
Uses include: UV light warning signs or advertising
CDL May 2015