Topic 10 Flashcards
What are ceramics?
ceramics are non-metal solids with high melting points that aren’t made from carbon based compounds.
What can ceramics be made from?
-clay
-glass
What happens when a ceramics made from clay is fired at a high temperatures?
it hardens to form clay ceramics
What type of glass is most glass made and how is it made?
Most glass made is soda-lime glass, which is made by heating a mixture of limestone, sand and sodium carbonate (soda) until it melts. When the mixture cools it comes out as glass.
How is borosilicate glass made.
It is made by heating a mixture of sand and boron trioxide.
How is borosilicate glass different to soda-lime glass.
borosilicate glass has a higher melting point than soda-lime glass.
What are composites made of?
composites are made of one material embedded in another
What do the properties of a composite depend on?
the properties of the materials it is made from (reinforcement), matrix/binder.
What are the fibres or fragments of a material also known as?
the reinforcement
What are some examples of materials that composites can be made from?
-fibreglass
-carbon fibre
-concrete
-wood
Describe fibreglass composites.
fibreglass consists of fibres of glass embedded in a matrix made of polymer. It has a low density but is very strong. It’s used for things like skis, boards and surfboards.
Describe carbon fibre composites.
carbon fibre composites also have a polymer matrix. the reinforcement is either made from long chains of carbon atoms bonded together (carbon fibres) or from carbon nanotubes. These composites are very strong and light so are used in aerospace and sports car manufacturing.
Describe concrete composites.
concrete is made from aggregate (a mixture of sand and gravel) embedded in cement. It’s very strong. This makes it ideal for use as a building material.
Describe wood composites.
wood is a natural composite of cellulose fibres held together by an organic polymer matrix
What are the important things that can influence the properties of a polymer?
how it’s made and what it’s made from
What does the monomers that a polymer is made from determine about the polymer chain.
the type of bonds that form between the polymer chain
What do the weak bonds between the different molecule chains determine about the polymer? Give some examples
the properties of the polymer for example:
-thermosoftening polymers contain individual polymer chains entwined together with weak forces between the chains. You can melt the plastics and remould them.
-thermosetting polymers contain monomers that can form cross-links between the polymer chains, holding the chains together in solid structure. Unlike thermosoftening polymers, these polymers don’t often soften when they’re heated. Thermosetting polymers are strong, hard and rigid.
Describe ceramics.
ceramics are insulators of heat and electricity, brittle and stiff.
Describe polymers.
polymers are insulators of heat and electricity, they can be flexible and are easily moulded. polymers have many applications including clothing and insulators in electrical items.
Describe metals.
Metals are malleable, good conductors of heat and electricity, ductile (they can be drawn into wires), shiny and stiff. Metals have many uses including in electrical wires, car body-work, and cutlery.
How are alloys made?
By adding another metal to the metal. This distributes the structure of the metal, making alloys harder than pure metals.
What are some examples of alloys used in everyday life?
-Bronze = copper + tin: Bronze is harder than copper. It’s used to make metals, decorative ornaments and statues
-Brass = copper + zinc: Brass is more malleable than bronze and is used in situations where lower friction is requires, such as in water taps and door fittings.
-Aluminium alloys are used to make aircraft: Aluminium has a low density which is an important property in aircraft manufacture. But pure aluminium is too soft for making aeroplanes so it’s alloyed with small amounts of other metals to make it stronger.
What is corrosion?
Corrosion is where metals react with substances in their environment and are gradually breakdown.
Which of iron, steel and aluminium corrode more?
iron and steel corrode much more than aluminium.
