Materials Summery

WEEK FOUR

Hello!! How are you, bloggers?

Today I hang up the summery about materials that I said last week. It treat about plastic, metals and smart materials; polymorph.
PLASTICS
Plastics are important nowadays, since they are light materials and most of them are resistant. Well, plastics divide in two groups:
· Thermosetting plastics
· Thermoplastics
The thermosetting plastics cannot be reheated to soften or mould. On this way, it is impossible to recycle this kind of plastics. Some examples of thermosetting plastics are adhesive, melamine formaldehyde, polyester resins or paints or varnishes compose of polyurethane.
On the other hand, thermoplastic have the characteristic of they can be reheated. And we can reutilize it many times that the materials permit it to us. Then we can find it for example in schools like acrylic. Or for example we can find polythene in toys, bottles or bowls. Apart from this kind of plastic in this group, the thermoplastic, there is the PVC (polyvinil chloride) that with it we can made some things like water pipes, raincoats, long play records, coating on electrical wires and many more.

Well, not all are plastic nowdays. We can chose between more materials like metals. In this group we can find two subgroups:
· Ferreous
· Non-ferreous metals
In the group of ferreous metals, all of them contais iron. And this group have some properties than the other group haven’t got. Therefore, the group of non-ferreous metals haven’t got iron in their composition. Below I put examples with the ferreous metals with their components and their properties.
Mild Steel
Carbon 0.1 - 0.3%
Iron 99.9 - 99.7%
Tough. High tensile strength. Can be case hardened. Rusts very easily.
Most common metal used in school workshops. Used in general metal products and engineering.
Carbon Steel
Carbon 0.6 - 1.4%
Iron 99.4 - 98.6%
Tough. Can be hardened and tempered.
Cutting tools such as drills.
Stainless steel
Iron, nickel and chromium.
Tough, resistant to rust and stains.
Cutlery, medical instruments.
Cast iron
Carbon 2 - 6%
Iron 98 - 94%
Strong but brittle. Compressive strength very high.
Castings, manhole covers, engines.
Wrought iron
Almost 100% iron
Fibrous, tough, ductile, resistant to rusting.
Ornamental gates and railings. Not in much use today.

Moreover I put another examples with some non-ferreous metals.

Aluminium
Light grey
Aluminium 95%
Copper 4%
Manganese 1%
Ductile, soft, malleable, machines well. Very light.
Window frames, aircraft, kitchen ware.
Copper
Reddish brown
Not an alloy
Ductile, can be beaten into shape. Conducts electricity and heat.
Electrical wiring, tubing, kettles, bowls, pipes.
Brass
Yellow
Mixture of copper and zinc 65% - 35% most common ratio.
Hard. Casts and machines well. Surface tarnishes. Conducts electricity.
Parts for electrical fittings, ornaments.
Silver
Whitish grey
Mainly silver but alloyed with copper to give sterling silver.
Ductile, Malleable, solders, resists corrosion.
Jewellery, solder, ornaments.
Lead
Bluish grey
Not an alloy.
Soft, heavy, ductile, loses its shape under pressure.
Solders, pipes, batteries, roofing.

A courious material it is the pholymorph. It belong to thermoplastic group. It will be able to shaped and reshaped many times that we want. It is sold like a granules. For working in this plastic, we have to boil water since 62 degrees centigrade. Then the polymorph will form a mass and we will be able to work with this mass.
Well, this is all the explanation above materials. I hope you find it interesting my readers.

See you soon!