corrosion

lead acid battery

used in vehicles, affected by temperature

common dry cell battery

zinc anode, graphite rod cathode

fuel cells

clean electruicty, hydrogen

iron and steel corrosion

rust

silver and copper corrosion

tarnish

protective layer

paint coating that acts as a barrier that prevents the transfer of electrochemical charge

paint can chip

galvanizing

impermeable barrier protection

sacrifical protection (more easily oxidized metal on top of meta you want to protect)

the coating develops a patina which can also protect agaisnt oxidation

can also chip

alloying

surface treatment

alloys the steel

nothing is exposed so the stell cannot rust

used in automotive and aerospace stuffca

cathodic protection

highly effective, sacrificial metal, requires maintenance

converts anodic sites to cathodic sites by supplying current from another source
the iron/steel becomes the cathode and does not corrode

for large things like boats and gas stations and pipes