6.15. Read the information in the table and find out which material (1-10) is best for:

a) water pipes

b) a knife for cutting a microscope lens

c) connecting a socket to the electricity supply

d) a bicycle frame

e) television casing

	Material	Properties	Uses
1	aluminium	light, easy to shape	aircraft, window and door frames, cooking foil
2	brass	doesn't rust in contact with air and water, strong	valves, taps
3	cement	mixed with water it dries to a hard material	pre-made building blocks, to hold bricks together
4	copper	easily made into wire, carries electricity well	electrical wire, tubing
5	diamond	hardest natural material, can cut glass and metal	industrial cutting and grinding
6	glass	clear, hard, breaks easily	windows, bottles
7	iron	Hard	engineering
8	mild steel (iron+0.15–0.3% carbon)	hard, strong, quite easy to shape	bridges, ships, cars
9	optical fibre	carries light and coded messages	lighting, cable TV, telecommunications
10	plastic	light, strong, easy to shape	hard hats, telephones, boats, computer casing

6.16. Discuss with a partner the following:

What properties should materials used in medicine have? Why?

6.17. Listen to the dialogue about materials used for body implants and answer the following questions:

1. What properties are important for them?

2. Which of them have been included in your list?

3. Which materials were recommended? Why?

6.18. Translate the text into Russian. Answer the question after the text.

Composite Ceramics

Advanced ceramic materials have such interesting properties that mechanical engineers are becoming more and more interested in their use as structural parts.

Ceramic cutting tools have been in use for some time. However, it is only during the last twenty years that there has been rapid development in this field because of the development of new composite ceramics.

Composite materials are materials in which two or more different substances, such as metals, ceramics, glasses, or polymers are combined without chemical reaction. As a result one can produce a material with properties different from those of any of the individual constituents. The constituents of a composite would retain their individual characteristics.

Recently engineers have developed various kinds of composite ceramics which must combine an increased toughness with the same hardness and strength of usual ceramics. A promising recent development is the addition of a tiny quantity of metal to increase toughness and tool life. Thus, at room and high temperatures (1000°C) the composite ceramics for cutting tools should possess the following properties: high strength, high toughness, high hardness, high thermal shock resistance and high chemical inertness.