ferrous and non-ferrous metals

• metals come from ores and are obtained by extraction via reacting with carbon or electrolysis
• ores are mined from the ground and smelted in a blast furnace
• • Metals are drawn off in a liquid state called ‘hot metal’ and the impurities are removed
  • The blast furnace reaches about 1,700°C to extract iron from iron ore
• material properties- ductile metals

  • stretched without being damaged
  • can be drawn and stretched into wires
  • copper is highly ductile and can be drawn into long thin wires
• material properties- malleable metals

  • can be hammered into a shape without breaking
  • can be rolled or pressed into sheets
  • will deform inf compressed
  • aluminium is used to make foil
• hardness- the ability to withstand abrasion

  • a very hard metal is likely to crack or shatter upon impact or force
  • cast iron would be described as hard but brittle
• toughness- in the ability absorb energy and not fracture

  • may scratch easily on the surface but can withstand large impacts
• physical structure of metal

  • the crystalline structure of metals can be modified through heat treatments
  • the larger the grains; the tougher and more ductile the metal

  
• molecular structure of metal- the atomic structure of metals shows the tight bonds between atoms

  • strong bonds between ions and electrons give high strength and melting points
  • positive ions make good conductors
• ferrous metals- contain iron and may rust

  • iron and steel can corrode- known as rust
  • rust = iron oxide, forms when iron and oxygen react in the presence of moisture
  • most ferrous metals are mganetic
• iron and carbon- steel combines iron and carbon which can also be alloyed with other elements

  • different element combinations ad ratios give different properties
• cast iron- has relatively high carbon content which makes it hard but britlle
• stainless steel- has high resistance to corrosion, staining and friction, doesn't require coating

  
  

  • alloy of carbon, chromium, nickel and manganese
• mild steel- tough, ductile and easy to machine, braze and weld

  
  

  • relatively low-cost material used in engineering and construction
• non-ferrous metals- do not contain iron and most are not magnetic

  
  

  • aluminium, copper and brass
• oxidisation- non-ferrous metals dot rust but may oxidise

  • can be caused by corrosion or weather exposure
  • tarnish that appears on the surface of the metal is - Patina
  • patina on copper is - Verdigris
• non ferrous properties- often more expensive due to their desirable properties

  • lightweight
  • good conductivity
  • ductile and malleable
  • resistant to corrosion
• brass- range of copper and zinc alloys with differing properties

  • hardness depends on ratio
  • corrosion resistance can be adjusted by adding lead or aluminium
  • used in padlocks, gears, valves, bearings, musical instruments
• aluminium- hugely versatile used in different shapes and forms

  • ore- bauxite, most common ore in the earth's crust
  • effective thermal insulator and doesn't degrade when recycled
• conductive copper- electrical conductivity is how easily an electrical current can flow through a metal