1. Materials

2. Materials
If we want to build a technical object that will withstand different constraints, it’s important to think about what materials we should use, and what properties these materials have.
Sometimes we can treat a material to prevent it from degrading and improve its ability to withstand constraints.
There are 5 types of materials to choose from

3. 5 materials Woods and modified woods Ceramics Metals and alloys
Plastics
Composites

4. 1. Wood and modified wood - Characteristics
Wood comes from trees (either softwood or hardwood)
Sometimes wood can be treated (i.e. with fragments glued together) to form modified wood, such as particleboard or plywood.
Wood is hard, resilient, and elastic.
It has low thermal and electrical conductivity.

5. 1. Wood and modified wood - Treatment
Wood comes from a living organism, so it can rot!
Don’t wash wood with water… just don’t.
Treat it with a basic copper solution or heat it to a high temperature.

6. 2. Ceramics- Characteristics
Ceramics are made by heating inorganic material, such as clays and sands that have oxides.
They are hard, resistant to corrosion, and have low electrical and thermal conductivity.
Used in space shuttles, kitchen equipment, and electrical insulation.

7. 2. Ceramics- Treatments
Avoid exposure to very strong acids and bases.
Avoid exposure to excessive temperature shocks.

8. 3. Metals and Alloys characteristics
A metal is a pure substance.
An alloy is a mixture involving a metal and something else (either metal or non-metal).
They are _________, _________, and good conductors of heat.

9. 3. Metals and Alloys Treatment
Metals can generally be coated to prevent oxidation.
They can also be made harder by rapid heating and cooling.

10. Obligatory bad science joke…

11. 4. Plastics - Characteristics
Made from fossil fuels such as petroleum and natural gas.
Thermoplastics are soft when heated. They can be molded and harden to hold their shape when cooled (recyclable ).
Thermosetting plastic remains hard, even when heated (and can’t be recycled  )

12. 4. Plastics - Treatments
Plastics can absorb water. This can be treated with a waterproof coating.
Plastics can be oxidized. This can be treated by adding an anti- oxidizing agent to its coating.
UV rays can damage plastic. Pigments can be added to absorb these rays.

13. 5. Composites These are combinations of materials containing 2 parts:
A matrix (frame or skeleton)
A reinforcement (between the matrix to give strength)
Common matrix material: plastic, metal, or ceramic.
Common reinforcement material: fiberglass, carbon fiber, kevlar