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c6 - corrosion - Coggle Diagram
c6 - corrosion
oil, grease, paint prevent corrosion
prevent corrosion by coating a metal with a barrier
this keeps out the water and oxygen
painting is ideal for large /small structures, also be nice and colourful
oiling/ greasing used when moving parts are involved eg. bike chains
coat of tin protects steel from corroding
tin plating- a coat of tin applied to object
tin acts as a barrier stops water and oxygen in air from reaching surface of metal
only works as long tin coating remains intact
if tin is scratched to reveal some of metal below starts to corrode
galvanising
coat of zin put of iron object to prevent rusting
zinc acts as scarificial protection and barrier
zincs more reacttive than iron so loses electrons to iron
steel buckets / corrugated iron roofing are galvanised
rusting of iron
if iron comes in contact with air and water after a while it will rust
rust is a form of hydrated iron oxide
redox reaction
iron loses electrons when it reacts with oxygen
irons oxidised
oxygen gains electrons when it reacts with iron
oxygens reduced
blocks of metal eg. mg
can be bolted to less reactive metals
mg. loses electrons to less reactive metal
used on ship hulls or underground pipes
more reactive metals can prevent metals corroding
called scarificial methods
place a more reactive metal with what you dont want to corrode, water and oxygen then reacts with this sacrificial metal instead of the metal ur protecting
rust equation
iron + oxygen + water >>> hydrated iron ( lll) oxide
other metals can corrode in the presecence of oxygen and water to form their metal oxides