✅ C6.1.13-6.1.16 materials Flashcards
Ceramics are what
Hard, non-metallic materials
4 examples of ceramic materials
Brick, china, porcelain, glass
What do ceramics contain
Metals + non-metals, combined to form giant ionic lattices or giant covalent structures .
4 typical properties of ceramics
- high melting points
- hard and stiff, but brittle
- poor conductors of electricity + heat
Reactivity of ceramics and why?
The compounds in ceramics are mostly oxides, and this makes them unreactive
Glass
- how made?
- made by melting sand, then allowing it to cool
Glass
- structure?
3
- glass has an irregular giant structure without crystals, and is usually transparent
Other ceramics - how are they made
Other ceramics are produced differently (to glass)
- they are made by heating clay to very high temperatures
- tiny crystals form, joined together by glass
- china and porcelain are usually coated in a glaze and reheated
- the glaze forms a smooth, hard, and waterproof surface
Desirable qualities for the material chosen for an overhead electrical cable?
(4)
So what type of material might be suitable ?
- good conductor of electricity
- lightweight
- strong, so does not stretch or snap easily
- resist corrosion
- Metals are good conductors of electricity
PIC - TABLE 1
Which metal best as an electrical cable?
- Copper best electrical conductor, but tensile strength low = it is not as strong when stretched as aluminium/steel
- also has highest density, so a copper cable will be very heavy
- Aluminium chosen.
- although it is not as strong as steel, it is a better conductor and less dense than steel
Desirable property for a material chosen to be an insulator ?
What kind of material (2)?
- insulators must prevent an electric current passing from the cable to the pylon
- should be poor conductor of electricity
- e.g. ceramics/polymers, rather than metals
Compressive strength vs tensile strength
compressive strength- A measure of how well a material resists being crushed when a force is applied.
tensile strength- The tension a material can withstand without breaking.
Basically, squashed vs stretched
ADD PIC TABLE 2
Which material should be chosen for an insulator?
- poly(propene) is a tough, flexible polymer
- it has the poorest electrical resistance of the three materials, and its tensile strength is the lowest = it would snap easily when stretched
- it also has the lowest compressive strength, so it would squash easily
- porcelain has a lower resistance than glass, but it has a higher compressive strength
- from the data in table, porcelain would be the most suitable for insulators where cables are fixed on top of a structure
Tell me about composite materials
- what is it?
- its properties? - and an example
- A composite material is made from two or more materials combined together, each with different properties
- The properties of a composite material are different from those of the materials it contains
- for example, it may be stronger, less dense, or cheaper than its separate components alone
- Your clothes are likely to be made from __ materials.
- Cotton fabric is __ and __ to wear, but it is not very __.
- Your clothes are likely to be made from composite materials.
- Cotton fabric is lightweight and comfortable to wear, but it is not very hardwearing.
- Polyester-cotton is a __ material made by weaving __ thread with __ fibre, an __ p__.
- it is still __, but __ wearing than cotton and easier to __ and __
- Polyester-cotton is a composite material made by weaving cotton thread with polyester fibre, an artificial polymer.
- it is still comfortable, but harder wearing than cotton and easier to wash and dry
Many composite materials consist of
Fibres + what polymer
- and so…. A + B = ?
- many composite materials consist of fibres embedded in a polymer resin
- these fibres have low density and high tensile strength but are brittle, whereas resin is hardwearing but is not strong
- the composite material is lightweight, strong, and hard
Fibreglass
- consist of?
- used for? (3)
- fibres glass consist of glass fibres in a resin
- it is used for canoes, boats, surfboards
Carbon fibre
- consists of?
- price vs fibreglass
- uses (3)
- consists of carbon fibres in a resin
- more expensive than fibre glass
- sports equipment, racing cars, aircraft parts
HOW COMPOSITES USED IN BUILDINGS:
Concrete
- consists of?
- hows it made?
- Concrete is a composite material that consists of aggregate (small stones), sand and cement
- when water is added to this mixture, chemical reactions happen that bind the ingredients together
Concrete + steel - composite material
- Compressive + tensile strengths of concrete?
- strengths of steel?
- so we do what?
- concrete gas a high compressive strength - it resists being squashed, so it is useful for foundations
- however, it’s tensile strength is low - concrete beams crack and break if you put heavy loads on them
- on the other hand, steel has a high tensile strength —
— by embedding steel rods in concrete as it sets, you het a composite material called steel-reinfected concrete. — THIS HAS high compressive strength and high tensile strength
WOOD - strength (GRAIN)
+ solution
- wood is a natural material consisting of long fibres lying side by side to make a ‘grain’
- wood is stronger along that grain, than across
- Plywood is a composite material in which thin sheets of wood are glued together in layers
- the grain in each layer is set at right angles to the layer below — this produces a composite material that resists bending in both directions, so it is useful for floors and walls
Glass ceramics
Glass is made by melting __, then allowing the molten liquid to __ and __. Glass is transparent and hard, but it is __.
Glass is made by melting sand, then allowing the molten liquid to cool and solidify. Glass is transparent and hard, but it is brittle.
Clay ceramics
Clay ceramics include __, __ and __. They are made by heating __ to __ temperatures, which causes __ to form and __ together. Clay ceramics are often coated with a __, which hardens on __ to form a h__, s__, o__ and w__ layer.
Clay ceramics
Clay ceramics include brick, china and porcelain. They are made by heating clay to high temperatures, which causes crystals to form and join together. Clay ceramics are often coated with a glaze, which hardens on heating to form a hard, smooth, opaque and waterproof layer.
Metals
Metals are __ and __, so they can be bent into shape or made into wires without shattering. Unlike glass and clay ceramics, metals are good electrical conductors.
Metals are malleable and ductile, so they can be bent into shape or made into wires without shattering. Unlike glass and clay ceramics, metals are good electrical conductors.
Polymers are __ conductors of electricity and heat, but their other properties vary depending upon the __ polymer. For example, they can be transparent or __. They are often tough and f__, but some are hard and b__.
Different polymers have different properties. This means that different polymers have different u__.
Polymers are poor conductors of electricity and heat, but their other properties vary depending upon the particular polymer. For example, they can be transparent or opaque. They are often tough and flexible, but some are hard and brittle.
Different polymers have different properties. This means that different polymers have different uses.
PIC OF COMMON POLYMERS
A composite material consists of __ or more materials with __ properties. They are combined to produce a material with __ properties.
Most composite materials have two components:
the __
the __, which binds the __ together
A composite material consists of two or more materials with contrasting properties. They are combined to produce a material with improved properties.
Most composite materials have two components:
the reinforcement
the matrix, which binds the reinforcement together
The table shows some examples of composite materials.
ADD TABLE OF COMP. PATERIALS
Reinforcement, matrix meaning
Reinforcement - Fibres or other material that make up the bulk of a composite material.
Matrix - The substance that binds the reinforcement together in a composite material.
It is often possible to separate the reinforcement from the matrix by __ processes. For example, concrete can be broken up using machinery. This is one stage in recycling the components of concrete.
It is often possible to separate the reinforcement from the matrix by physical processes. For example, concrete can be broken up using machinery. This is one stage in recycling the components of concrete.
Fibreglass and carbon fibre reinforced polymer
The fibres in these composite materials have a low __. They are strong in __, so they are not easily stretched, but they are __.
The polymer resin which binds the fibres together is not strong, but it is s__ and hardwearing. The composite materials show a combination of these properties. They are strong, stiff, hard and l__.
Fibreglass and carbon fibre reinforced polymer
The fibres in these composite materials have a low density. They are strong in tension, so they are not easily stretched, but they are brittle.
The polymer resin which binds the fibres together is not strong, but it is stiff and hardwearing. The composite materials show a combination of these properties. They are strong, stiff, hard and lightweight.
Chipboard
Wood itself is a natural composite material. It consists of a reinforcement of c__ fibres bonded together by a matrix of l__. The fibres are aligned alongside each other, so wood is stronger in one d__ than it is in the other.
Chipboard contains r__ arranged wood chips bonded together by a g__, so it is s__ in all directions.
Chipboard
Wood itself is a natural composite material. It consists of a reinforcement of cellulose fibres bonded together by a matrix of lignin. The fibres are aligned alongside each other, so wood is stronger in one direction than it is in the other.
Chipboard contains randomly arranged wood chips bonded together by a glue, so it is strong in all directions.
Chipboard may be supplied with a thin polymer layer glued to its surfaces. Suggest reasons that explain why this material is more suitable than chipboard alone for making self-assembly furniture.
The polymer can be coloured or patterned to look like wood. It makes the surface waterproof so it is protected from spills and can be cleaned more easily.
The properties of concrete can be improved by reinforcing it with s__ rods or m__. The compressive strength of concrete is higher than its __ strength, but the tensile strength of __(material) is higher than its compressive strength. The combination of the two materials is strong in t__ and in c__. Reinforced concrete is therefore strong and slightly f__, whereas concrete alone is b__.
The properties of concrete can be improved by reinforcing it with steel rods or mesh. The compressive strength of concrete is higher than its tensile strength, but the tensile strength of steel is higher than its compressive strength. The combination of the two materials is strong in tension and in compression. Reinforced concrete is therefore strong and slightly flexible, whereas concrete alone is brittle.
BBC PIC
(a) Identify the weakest metal shown in the table, and explain your answer.
(a)The mild steel is the weakest METAL, although timber is the weakest material of the three. Mild steel has a lower tensile strength than aluminium, so it stretches more easily when forces are applied. It has a lower compressive strength, so it is crushed more easily when forces are applied.
BBC PIC
(b) All three materials could be used to make the frame for a train carriage. Evaluate these materials for this use.
Timber has the lowest density, so a wooden frame could be the most lightweight. However, timber is the weakest material, so the frame will need to be thicker or use more pieces. This might make the wooden frame heavier than a metal frame.
Mild steel is almost as strong as the aluminium alloy. However, it is 2.75 times denser than aluminium, so a steel frame is likely to be much heavier. A heavier carriage may reduce the number of carriages the train can pull, or reduce its acceleration so that journey times increase.
The aluminium alloy is four times denser than timber, but at least 19 times stronger. An aluminium frame is likely to be the most lightweight of the three materials. Aluminium alloy has a good resistance to moisture. Unlike mild steel and timber, it does not need protecting. Overall, aluminium alloy would be the best choice.
Kerboodle POLYMER PIC
Evaluate - best for a plastic cup?
- although polythene is the cheapest, it is unsuitable
- boiling water will not melt it, but the cup will become too soft to hold safely
- PET is the most expensive and, although it has the highest tensile strength and melting point, hot drinks will soften it too
- polypropylene is the most suitable as its maximum usable temperature is above 100C and it has a high tensile strength
What is a life-cycle assessment?
A life-cycle assessment (LCA) is a ‘cradle-to-grave’ analysis of making, using, and disposing of a manufactured product.
Life-cycle assessments should include data about (4)
- sustainability, including the use of raw materials and energy
- environmental impact, including waste products and pollution
- the lifespan of the product and whether any of it can be recycled
- disposals, including how easily the materials decompose (break down)
Examples of data that may need to be collected in ‘cradle’ (3)
- raw materials obtained and processed to make useful materials
- materials used to make the product
- energy and wafter used in processing and manufacturing
Examples of data that may need to be collected in ‘use’ (3)
- energy needed to use the product (e.g. electricity needed for a computer)
- energy needed to maintain the product (e.g. cleaning, mending)
- water and substances needed to maintain it
Examples of data that may need to be collected in ‘grave’ (2)
- energy needed to dispose of the product
- space needed to dispose of it
How can you use life-cycle assessment data?
- data.collected from an LCA should allow you to identify stages that could be improved
- for example, an LCA for a pair of trousers might show that 20% of the total energy is used in its production, 75% in its use, and 5% in its disposal
- it would make little sense to try and save energy at the disposal stage
- however it would be worthwhile to investigate how to use less energy when washing and drying the trousers, since most energy is used at this stage
A life-cycle assessment or LCA is a ‘__-to-__’ analysis of the impact of a manufactured product on the __. There are many detailed stages but the main ones are:
- obtaining the __ materials needed
- m__ the product
- u__ and m__ the product
- d__ of the product at the end of its useful life
A life-cycle assessment or LCA is a ‘cradle-to-grave’ analysis of the impact of a manufactured product on the environment. There are many detailed stages but the main ones are:
- obtaining the raw materials needed
- manufacturing the product
- using and maintaining the product
- disposing of the product at the end of its useful life
The four main stages
At all stages, an LCA is likely to include information about the use of e__, t__ of materials, and the release of w__ substances into the e__.
The four main stages
At all stages, an LCA is likely to include information about the use of energy, transport of materials, and the release of waste substances into the environment.
- Raw materials
All the raw materials we need come from the Earth’s crust, atmosphere or oceans, or are due to __ organisms. Obtaining these materials has an impact on the environment, including:
- using up l__ resources such as o__ and __ oil
- damaging habitats through q__, m__, or f__ trees
- Raw materials
All the raw materials we need come from the Earth’s crust, atmosphere or oceans, or are due to living organisms. Obtaining these materials has an impact on the environment, including:
- using up limited resources such as ores and crude oil
- damaging habitats through quarrying, mining, or felling trees
- Manufacture
The manufacture of products has an impact on the environment, including:
- using up l__ for factories
- the use of m__ and p__
- Manufacture
The manufacture of products has an impact on the environment, including:
- using up land for factories
- the use of machines and people
- Use
The impact of a product on the environment during its use depends on the t__ of product. For example, a wooden chair has very little impact, unless it needs c__ or r__. On the other hand, a car will have a significant impact, because its use depends on burning __ __ which releases p__.
- Use
The impact of a product on the environment during its use depends on the type of product. For example, a wooden chair has very little impact, unless it needs cleaning or repair. On the other hand, a car will have a significant impact, because its use depends on burning fossil fuels which releases pollutants.
- Disposal
The disposal of old products has an impact on the environment, including:
- using up land for l__ sites
- whether any or all of the product can be r__ or r__
- Disposal
The disposal of old products has an impact on the environment, including:
- using up land for landfill sites
- whether any or all of the product can be recycled or reused
SO AGAIN. The 4 main stages of life cycle assessment
- raw materials
- manufacture
- use
- disposal
spec:
-making materials for a product from raw materials through to the processes used to make the product
- the use of the product
• transport of the product
• the method used for its disposal at the end of its life
BBC BIT TABLE
Discuss the use of energy during the life-cycle of the pillowcase, and describe one way in which the energy use could be significantly reduced.
One quarter of the energy use is associated with making the pillowcase, and very little in disposing of it. The greatest use of energy happens when it is being used, probably because of washing, drying and ironing the pillowcase. Energy use could be reduced by drying it outside and without ironing it.
Where will most materials and products end up, if not recycled
- in landfill sites as waste
- disposal like this is not an efficient use of resources
3 reasons recycling is important
- conserving limited raw materials and energy resources
- reducing the release of harmful substances into the environment
- reducing waste
What is saved from recycling metals rather than extracting them from ores
Energy
4 factors that determine whether or not a particular material or product should be recycled:
- how easily the waste can be collected and sorted
- the amount and type of any by-products released by recycling
- the cost of recycling compare to disposal in landfill or by incineration (burning)
- the amount of energy involved at each stage
How are materials recycled - first steps
- waste materials and products must be collected and transported to a recycling plant
- it helps if the different materials have already been sorted, but more sorting is usually needed at the plant
- it is important to ensure that, for example, glass is not contaminated by metal bottle tops
- the sorted waste is then shredded or crushed into smaller pieces ready for processing
Recycling materials:
During processing.
- metals
- metals are melted by heating + impurities removed from the molten metal
- the molten metal is poured into moulds (and solidify) to produce new blocks called ingots
The ingots can then be used to manufacture new metal items.
Recycling materials:
During processing.
- paper
- paper is mixed with water, cleaned, the rolled and heated to make new paper
Recycling materials:
During processing.
- glass
- glass is melted by heating
- and mounded into new glass objects
Recycling materials:
During processing.
- polymers
- polymers like poly(ethene), PET, and poly(propene) are melted
- and formed into new objects
Bbc bitsize, advantages of recycling (4)
- fewer oil wells, quarries or mines are needed
- less noise, dust and heavy traffic are produced
- smaller areas of natural habitats are damaged
- (in addition)less energy is usually needed to produce a material by recycling than is needed to produce it from its raw materials
Bbc bitsize, disadvantages of recycling (3)
- the collection and transport of used items needs organisation, workers, vehicles and fuel
it can be difficult to sort - different materials from one another
- the sorted materials may need to be transported to where they can be processed
Describe a simple way to separate aluminium from iron.
A magnet or electromagnet will attract iron but not aluminium.
Metal Energy saved (%)
Iron 70
Aluminium 92
Suggest an explanation for the difference.
Aluminium is extracted from its ore using electrolysis but iron is extracted by heating with carbon. Electrolysis uses more energy, so more energy is used to extract aluminium in the first place. Aluminium has a lower melting point than iron, so less energy is needed to melt it during recycling.
What can ingots be used for?
The ingots can be used to manufacture new metal items.
Waste materials such as polymers and metals are often disposed of in __ sites. Waste polymers may be i__. However, these disposal methods waste valuable resources, including these raw materials:
- __ oil for making most polymers
- metal __ for making most metals
These are __ resources - they form extremely slowly or are no longer being made. Recycling reduces the problems of d__, and also conserves r__ materials.
Waste materials such as polymers and metals are often disposed of in landfill sites. Waste polymers may be incinerated. However, these disposal methods waste valuable resources, including these raw materials:
crude oil for making most polymers
metal ores for making most metals
These are finite resources - they form extremely slowly or are no longer being made. Recycling reduces the problems of disposal, and also conserves raw materials.
