Making our resources p2 Flashcards
(34 cards)
Define corrosion
when a material reacts with substances in the environment and eventually wears away
what 2 ways can corrosion be prevented
physical barriers
sacrificial protection
define physical barriers (to prevent corrosion)
give example
material covered with physical barriers like grease, paint or a thin layer of another metal by a process called ELECTROPLATNG
example:
aluminium reacts with oxygen in air to form thinnoayer of aluminium oxide around metal
This layer protects the rest of the metal from corrosion
define sacrificial protection
+example
more reactive substance placed on material
this will react with the environment (not main material)
example:
iron is galvanised with zinc
zinc reacts with oxygen and water in place of iron
what is rusting
example of corrosion
caused by iron reacting with oxygen and water from environment
what is bronze an alloy of
copper and tin
what is brass an alloy of
copper and zinc
what is high carbon steel an alloy of
iron with 1-2% carbon
what is low carbon steel an alloy of
iron with <1% carbon
what is stainless steel an alloy of
iron with chromium and nickel
properties of bronze
resistanct to corrosion
what are gold alloys made of
mostly gold with copper, silver and zinc added
properties of brass
very hard but workable
properties of gold alloys
attractive, corrosion resistant, hardness depends on carat
properties of hugh carbon steel
strong, but brittle
properties or low carbon steel
soft, easy to shape
properties or stainless steel
resistant to corrosion
hard
properties of aluminium alloys
low density, properties depend on composition
name 3 ceramics
soda-lime glass
borosilicate glass
clay ceramics (pottery+bricks)
how to make soda-lime glass
heat mixture of sand, sodium carbonate, limestone
how to maje borosilicate glass
heat sand and boron trioxide
how to make clay ceramics
shape wet clay then heat in a furnace
properties or soda-lime glass
transparent, brittle
