Alloys and Corrosion Flashcards
What physical properties do transition metals have?
- High melting and boiling points (except mercury which is a liquid at room temperature
- High density
What chemical properties do transition metals have?
- Form coloured compounds
- Catalytic activity (useful as catalysts)
What are the properties of group 1 and 2 metals?
- Low melting and boiling points
- Low density
- Formation of white or colourless compounds
- Lack of catalytic activity
(Basically the opposite properties of transition metals)
How is rusting prevented?
- Painting over the iron or steel
- Using oil or grease
- Coating with plastic
- Electroplating
How does electroplating work?
A thin layer of an unreactive metal is deposited on the surface of the metal object
Why are metals electroplated?
- To improve their appearance
- To make them resistant to corrosion
What is an alloy?
A mixture of a metal with one or more other element, these other elements are usually other metals or carbon
What is stainless steel?
An iron alloy that is resistant to corrosion
How is stainless steel resistant to corrosion?
It has an invisible thin layer of chromium oxide on the surface of the steel which stops air and water from reaching the iron
What are the uses of carbon steel?
Buildings, bridges, cars - this is because carbon steel is hard and strong
What are the uses of jewellery gold?
Jewellery, it looks nice and is resistant to corrosion so it stays shiny
What are the uses of brass?
Electrical plugs, coins - hard, resistant to corrosion and is a good electrical conductor
What is steel?
An iron alloy that is made because iron is too soft for most purposes
