Use the techniques you have learnt in previous lessons To learn about metals To give you a broader understanding of the materials used in everyday products Part of your GCSE exams and materials that you might want to use for your future projects Use the techniques you have learnt in previous lessons

Properties, Ferrous, Alloys, Finish Objective To learn about Metals their properties and uses Key words Properties, Ferrous, Alloys, Finish

General properties of metals Strength – How well a material can resist being deformed. Lustre – A gentle sheen or soft glow Conductivity – Ability to allow electrical current to pass through a material. Tough The ability to withstand impact Hard Ability to withstand scratching Ductile Ability to stretch without breaking (thin wires) Malleability Ability to be shaped (i.e. with a hammer) Without breaking. General properties of metals Materials that do not let electricity pass through them easily are called electrical insulators. Plastic, wood, glass and rubber are good electrical insulators. Copper is used to make electrical wiring because it is a good conductor of electricity Iron is used to make cars and bridges because it is hard, with a high tensile strength Metal form ability ROD IS CIRCULAR AND A BAR IS RECTANGULAR Metal categories It is assumed that Iron was discovered in South East Asian region about 4000 years ago. At that period, Iron was rated more expensive than gold. In 1200 BC, the  "Iron Age" begun. In this period, the method of extraction and working method improved. Dental fillings are an alloy (mercury and amalgam) Solder (ie lead and tin) Carbon is not a metal but is a natural substance- l diamond and graphite are both carbon substances-Diamond is the hardest natural substance on Earth, but it is also very brittle and will shatter if hit with a hammer. Non F metals It is a common alloy for general use and, inaerospace applications, is used for wing and fuselage structures. ... Lightweight with excellent corrosion resistance, less flammable

Material Form Availability Metal Bar (or Rod) Metal Angle Metal Sheet Metal Tube What is the difference between bar/rod and tube?

Metal Categories Ductility Ferrous Metals Non-Ferrous Alloys Ability of a material to stretch without breaking Metal Categories Ferrous Metals Non-Ferrous Alloys Contains Fe – Iron Iron is soft and ductile, not particularly useful. When carbon is added, it becomes steel and its properties are improved. Do not contain Fe –iron Two (or more) metals are combined to produce materials with enhanced properties such as changes to: colour, strength, hardness etc. Example: adding zinc to copper (brass) produces a much harder and stronger material than pure copper. It is assumed that Iron was discovered in South East Asian region about 4000 years ago. At that period, Iron was rated more expensive than gold. In 1200 BC, the  "Iron Age" begun. In this period, the method of extraction and working method improved. Dental fillings are an alloy (mercury and amalgam) Solder (ie lead and tin) Carbon is not a metal but is a natural substance- l diamond and graphite are both carbon substances-Diamond is the hardest natural substance on Earth, but it is also very brittle and will shatter if hit with a hammer.

Ferrous Metals Add the missing information to your table of Ferrous metals BASE MATERIAL Carbon % TYPE OF STEEL DUCTILITY HARDNESS TOUGHNESS Uses IRON MILD STEEL Nuts, bolts, washers MEDIUM CARBON STEEL Gardening tools HIGH Hand tools, scribers, chisels CAST IRON BRITTLE Machine parts, brake discs, engines carbon content increases Less carbon- ductility increases More carbon- harder Less carbon- toughness decrease.

Non-Ferrous metals Drinks cans, aircraft bodies. Oxide – oxygen combined with another chemical Add the missing information to your table of Non Ferrous metals\ METAL COMMON USES Properties Aluminum Drinks cans, aircraft bodies. Soft, malleable, It is corrosion resistant - A layer of oxide protects it from corrosion Copper Electrical contacts, electrical cable and wire, jewellery. Tough, ductile, High electrical conductor, corrosion resistant. It is a common alloy for general use and, inaerospace applications, is used for wing and fuselage structures. ... Lightweight with excellent corrosion resistance, less flammable

Valves and taps, boat fittings. ornaments Statues, coins, bearings Metal Alloys Add the missing information to your table of Alloys NAME BASE METAL Properties COMMON USES BRASS Copper Strong, wear resistant, hardness (harder than bronze) Valves and taps, boat fittings. ornaments Bronze Hard, Strong, Doesn’t corrode easily, Shiny surface Statues, coins, bearings

Protective finishes for metals We apply finishes to metals to protect them against corrosion and to improve their aesthetic appeal. Galvanising Paint/Lacquer (varnish) Iron or Steel is dipped in a bath of molten Zinc Prevents rusting/ corrosion. Surface must be smooth & de-greased Multiple layers of varnish is applied Painting - Primer required Plastic Coating Enamelling Suitable for most metals Object is heated and dipped in a tank of powder paint Object is returned to oven to ensure a smooth, glossy finish. Powdered glass is melted onto the metal surface Provides a hard (but brittle) finish with different colours and textures.

Exam Style Questions Ductile A conductive metal It is resistant to corrosion so will not rust. Good lustre- so shiny and attractive.

Ductile Need to be able to stretch it thin without it breaking for the can. It means the characteristics of materials, often describing how they perform under certain conditions like when stretched or are under pressure.