Page 54 - Science Class 08

v In the last 30 years, different aluminium bronze which started to be widely used
alloys have been made that are an - because it was stronger than copper as well as
corrosion, strong, tough yet very light and n. It was used par cularly for making knives,
resistant to sea-water as well. spears and other sharp tools and implements.

About Alloys It was much later that ornamental alloys came
The earliest alloys were made in the pre- to be made when gold and silver started to be
historic me by ancient people when they mined as pure metals.
came to know about metals. Those alloys were These alloys were made keeping two points in
made using metals that were available in view:
plenty and could be easily melted. The first two
v To maintain the shine of gold. For it, gold
metals to be discovered by early men were
was alloyed with copper to get yellow gold.
copper and n. So, the first alloy came to be
discovered when these two metals accidentally v To bring the cost of gold a li le down so
melted together and hardened. This alloy was that people could buy it.

Alloy Cons tuent Metals Use

Alnico iron, aluminum and nickel magnets and cobalt

Brass copper and zinc utensils, parts of machinery,

wires,musical instruments
and ornamental objects
Bronze copper and n statues, ornaments, bells,
medals, coins, cooking utensils

and aircra parts.

Duralumin aluminum and manganese aircra , copper and magnesium

Magnelium aluminum and magnesium aircra industry

Nichrome nickel, iron and chromium electric hea ng and
manganese elements

Stainless steel iron and chromium construc on of ships, tanks,
bridges, railway lines and
machinery
Steel iron and carbon cooking utensils, nickel cutlery
and surgical instruments

Sterling silver silver and copper silverware and jewellery

Solder lead and n electrical connec ons

54 Science-8