materials and their properties

• ceramics


  non-metal solids with high melting points that aren't made from carbon-based compounds
• some ceramics can be made from...

  clay
• clay


  a soft material when it's dug up out of the group that can be moulded into different shapes when wet. when it's fired at high temperatures it hardens to form clay ceramic
• clay uses


  pottery and bricks
• glass


  a transparent fusion product of inorganic substances that have cooled to a rigid state (which is brittle when thin) without crystallising and can be moulded when hot
• soda-lime glass


  the most common glass, which is made by heating a mixture of sand, sodium carbonate and limestone and when it cools it comes out as glass
• borosilicate glass


  glass made from sand and boron trioxide and it melts at higher temperatures than soda-lime glass.
• composites


  materials made of two or more different materials embedded in each other. fibres or fragments of a material (known as a reinforcement) are surrounded by a matrix acting as a binder
• the properties of a composite depend on...

  the properties of the materials it is made from
• fibreglass


  - consists of fibres of glass embedded in a matrix made of polymer (plastic)

  - has a low density (like plastic) but is very strong (like glass)

  - used for skis, surfboards and boats
• carbon fibre


  - have a polymer matrix and the reinforcement is either made from long chains of carbon atoms bonded together (carbon fibres) or from carbon nanotubes

  - very string and light

  - used in aerospace and sports car manufacturing
• concrete


  - made from aggregate (any material made from fragments, such as sand and gravel) embedded in cement

  - very strong

  - ideal for use as building material (e.g. in skate parks)
• woods

  a natural composite of cellulose fibres held together by an organic polymer matrix
• what influences the properties of a polymer?

  - how it is made (the catalyst used and the reaction conditions (the temperature and pressure) it was made under

  - what it is made from (the monomers that determine the type of bonds (weak or strong) formed between the polymer chains)
• low density poly(ethene)


  - made from ethene at a moderate temperature under a high pressure and with a catalyst

  - flexible and is used for bags & bottles
• high density poly(ethene)


  - made from ethene at a lower temperature and pressure with a catalyst

  - rigid and is used for water tanks & drainpipes
• thermosetting polymers


  - have cross links holding the polymer chains together in a solid structure

  - cross links do not break when heated

  - polymer does not soften when heated

  - strong, hard and rigid
• thermosoftening polymers


  - contain individual polymer chains entwined together with weak forces between the chains

  - weak intermolecular forces break when heated

  - polymer softens when heated

  - plastics can be melted and remoulded
• ceramic properties


  - non-conductive

  - insulators of heat

  - brittle

  - hard

  - strong in compression

  - weak in tension

  - high melting point
• polymer properties


  depends on chemical composition, degree of polymerization, intermolecular forces, copolymer, and morphology of polymer
• composite properties


  depends on the matrix/binder and the reinforcement used to make them, so they have many different uses
• metal properties


  - good conductors of heat and electricity

  - malleable

  - solid at room temp

  - shiny

  - stiff

  - ductile
• alloys


  a mixture composed of two or more elements, at least one of which is a metal
• why are alloys harder than pure metals?

  the different sized atoms of the metals distort the layers in the structure, making it more difficult for them to slide over each other
• steel


  an alloy of iron and carbon (and sometimes other metals)
• alloy uses in manufacturing

  - steel alloys: used in car bodies, tools, and surgical instruments

  - aluminium alloys: used in vehicle frames and other components for their lightweight properties

  - magnesium alloys: used in aerospace and automotive industries for their strength-to-weight ratio

  - nickel-based superalloys: used in jet engines and gas turbines due to their high strength and heat resistance
• alloy uses in everyday appliances

  - stainless steel: used in cookware, cutlery, and kitchen appliances for its corrosion resistance.

  - bronze: used in coins, medals, musical instruments, and sculptures.

  - brass: used in musical instruments, door knobs, locks, and taps.

  - solder: used for joining copper pipes and electrical components.
• alloy uses in scientific applications

  - special metal alloys: used in joint replacements, pacemakers, stents, and surgical tools.

  - beryllium-copper alloys: used for non-sparking tools.

  - alloys in electronics: used in various electronic components