Non-Ferrous Metals

Non-ferrous metals are the metals not composed of or containing iron. Non-ferrous metals are more expensive than ferrous metals and are used only when some characteristics not possessed by iron or steel are essential or desirable in application. These characteristics are: high electrical and thermal conductivity, high corrosion resistance, non-magnetic qualities, light weight, etc.

The metals most frequently used to make non-ferrous metal castings are copper, tin, zinc, lead, nickel, gold and aluminum. As it has been said before, copper was one of the first metals to be used. In its natural form, copper occurs in the ground as copper ore, a mineral. But this ore contains only 0.5 - 1 per cent of the metal. The rest is rock. The world produces 9.6 million tons of copper a year. This means that more than a thousand million tons of ore must be removed from the ground to extract pure copper. Pure copper is a reddish, tough metal. It has very high electric conductivity and high corrosion resistant qualities. Copper is used for making electrical contacts and wires, pipes, telephone cables, tanks, water heaters, etc.

Zinc is a moderately hard, brittle metal which acquires a protective coating of zinc oxide on its surface. It burns in oxygen and in chlorine with a bluish flame. Its colour is yellow when hot and white when cold. Zinc oxide is used in paints because it is non-poisonous and is not discoloured by hydrogen sulfide. It has a soothing effect upon the skin and is used in ointments and lotions. It is added to rubber for making racing motor tyres.

Zinc is used in the production of dry batteries and in the process of galvanizing. In this, iron is dipped into molten zinc which forms a protective layer on its surface and so prevents rusting. Galvanized iron is used in sheets for roof­ing as well as for buckets and dustbins.

Lead is now a very expensive metal. At one time it was used extensively for roofing and for water piping because of its softness and resistance to corrosion, but copper and iron have taken its place. Lead is a very heavy grey malleable metal which melts at 327° C, which is low for a metal. Its strength is so low that it must be supported by a core of some other metal. Lead is still used for roofing and for making waste pipes (because it is easily bent into shape), storage battery plates, coating of electric cables, storage tanks for sulfuric acid, screens to stop harmful radiation from radioactive substances. Lead was widely known in Roman times. Some Roman aqueducts still stand today because they were lined with lead, and lead does not rust. Many thousands of tons were used in a single aqueduct. So much lead was used in water-supply systems that eventually the Romans suffered some lead-poisoning.

Aluminum is a silvery white and ductile metal. It is the most abundant metal in the Earth's crust. It makes up about 8% by weight of the Earth's solid surface. Aluminum is too reactive chemically to occur in nature as a free metal. Instead, it is found combined in over 270 different minerals. The chief source of aluminum is bauxite ore. The main mining areas for this ore are in Ghana, Indonesia, Jamaica, Russia and Surinam.

Aluminum is the oldest and best known light metal. It does not rust in air. It is soft, that is why it is used only when alloyed with other metals. The addition of small quantities of other metals in the making of alloys produces materials which are light but very strong. Aluminum is one of the commonest metals in industry. Low weight and resistance to corrosion combined with its toughness make aluminum very suitable for parts of cars. It is used for making cooking utensils, ladders, refrigera­tors, chairs, etc. Its shiny surface reflects heat, and aluminum foil is used for the heat insulation of houses. Aluminum paint protects iron­work from rust, and reflects light. Structural components made from aluminum and its alloys are vital to the aerospace industry and are very important in other areas of transportation and building.

Tin was the fifth metal discovered by man. Tin is a malleable, silvery, corrosion-resistant metal. It is used to coat other metals to prevent corrosion, but it is rarely used in pure form. It is employed as an alloying element.

Nickel is a hard, tough, silvery metal. It has high corrosion-resistant qualities and is used for plating other metals such as iron and brass.

1. Find in the text English equivalents for the words and -word-combinations:

По вазі, в інших областях, теплоізоляція, зустрічатися в природі, захисне покриття, самий поширений метал, отруєння свинцем, системи водопостачання, хімічно реактивний, відповідний, замість цього, блискуча поверхня, невелику кількість, відбивати тепло, найбільш часто, холодильники, рідко використовується.

1. Answer the questions:

1. What metals are called non-ferrous?

2. What are the most important properties of non-ferrous metals?

3. What properties does pure copper possess?

4. Where is zinc used?

5. What do you know about the properties and application of lead?

6. What properties of aluminum make it one of the commonest metals for industry?

7. Does tin rust in air?

8. What is nickel mostly used for?