Making Metals More Useful Flashcards
What is most pure iron changed into?
Alloys called steels
How are steels formed?
By adding small amounts of carbon and sometimes other metals to the iron
Why are the alloys produced better than the original metals?
They’re stronger and more corrosion resistant
Why are alloys harder?
Different elements have different size atoms. When an element such as carbon is added to pure iron, the smaller carbon atom will upset the layers of pure iron atoms, making it more difficult for them to slide over each other
What are gold alloys used to make?
Jewellery
Why are gold alloys used to make jewellery?
Pure gold is too soft, so metals such as zinc, copper and nickel are used to harden it.
How is pure gold in an alloy described?
By carats or fineness
Describe carats
Pure gold is describes as 24 carat, so 18 carats means that 18 out of the 24 parts of the alloy are pure gold.
Describe fineness
Fineness refers to the parts of pure gold per thousand
What is an alloy?
An alloy is a mixture of two or more metals, or a mixture of a metal and a non metal.
What do smart alloys do?
Some smart alloys have a shape memory property, this means they return to their original shape when heated
Give an example of a smart alloy.
Nitinol, an alloy of nickel and titanium
What is nitinol used for?
Glasses frames
Stents for use in damaged blood vessels
