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1.3 Enhancement of Materials - Coggle Diagram
1.3 Enhancement of Materials
Polymers
Lubricants - adding wax or calcium stearate reduces viscosity of molten polymer, so its less sticky, allows more intricate shapes to be formed, allows moulding temp to be lowered - saving energy
Thermal Antioxidants - prevents oxidising or discolouring de to excessive heat during processing
Pigments - tiny particles are mixed with polymer in molten state to give colour to final processed product
Antistatics - reduce the likelihood of polymer building up static charge
Flame Retardants - reduce likelihood -of combustion or spread of fire or potential electrical fires
Plasticisers - allows plastics to be less hard & brittle at normal temp, also help in processing- allow polymers to be easily formed at higher temps
Fillers - sawdust and wood flour provide bulk to product, less polymer is required, mineral fillers increase the thermal conductivity, heats and cools quicker shorter mould cycles
Biodegradable Plasticisers - make polymer more flexible, softer, easier to break down - faster degradation time
Bio-Batch additives - oxy-degradable, photodegradable and hydro-degradable additives reduce degradation time from 100+ years to only a few years/months
Antitoxidants - reduce environmental deterioration of polymer from exposure to oxygen, prevents increased brittleness, surface cracks and pigment discolouration, used in polymer garden furniture
UV Light Stabilisers - prevent breakdown by sunlight, used in outdoor toys & play equipment, garden furniture, sports stadium seats, astroturf
Woods
Resins & Laminations - used in engineered wood to enhance properties of sawdust, woodchips and fibres, chipboard is made from compressing wood chips with resin, very stable and not affected by temp and humidity, uniform strength, no grain problems
Resins with Fire Retardants - resin is impregnated with fire-retardant cladding
Laminations - veneers such as natural wood are laminated onto board surface to enhance aesthetics
Preservatives - protect wood against fungal and insect attack, wood can be pre-treated with copper based preservatives, penetrate wood to protect plank, copper has good fungicidal properties
Pigments - added to preservatives to give colour - aesthetics, can be used on softwoods to look like hardwoods
Fire-Retardant Preservatives - used to pressure treat wood for roof joists, cladding and exhibition stands, wood can be treated to make it harder and more resistant in high-wear situations
Modified Natural Polysaccharide - wood is impregnated to cure within cell structure, increases hardness, toughness and stability
Structural Composite Lumber & Laminated Veneer Lumber - made by layering stands (SCL) or veneers (LVL) of wood with resins pressing and heat curing them to produce stable wood billet, less prone to defects and greater load-bearing properties, used in structural applications
Metals
Work Hardening - when metal is cold worked - bending, rolling, hammering - crystals in metal are distorted and changed, improving tensile strength and hardness. When crystals are distorted they cannot move freely within metal structure - less ductility, cracking or damage - affects of this can be removed by annealing the metal
Annealing - used to make the work-hardened metal easier to work, so its less brittle and more ductile. metals heated and then cooled slowly, allowing metal crystals to grow and move into place
Case Hardening - used for hardening the surface of low carbon steels (<0.4%), produces an outer casing of greater hardness, improved wear resistance and resistance to surface indention, while inner core retains original softer properties.
1 - Carburising - changes the composition of surface of the LCS so it can also absorb more carbon to increase surface hardness, in industry - steel is placed in ceramic box that is packed with carbon, box is heated, carbon atoms diffuse into materials structure to build up surface carbon content. depth of carbon layer is determined by length of time materials is exposed to carbon. Longer time, thicker layer, product is then heated then quenched
2 - Quenching - hot metal is quenched in water is fast-cool it and seal hard surface case while not affecting properties of inner core
Hardening - Medium and high carbon steels are heated to alter their crystalline structure, holding them at this temp for given time, then quenching them in water, oil or salt-water baths. hardening and then quenching increases hardness but it increases brittleness
Tempering - heat treatment reduces some excess hardness & brittleness of hardened metal, and increased toughness and ductility. Metal is heated to below critical point for given time then slowly air-cooled. The exact temp will determine the amount of hardness removed. Tempering colour on metal indicates the temp at which brittle is removed
can be enhanced through controlled application of heating and cooling, heat treatment
enhancement is a way of improving materials properties to better suit requirements of final product