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COATING MATERIALS - Coggle Diagram

- - - - Waterbased gold and silver coatings
      - UV based silver coatings (cures under UV, vacuum metallization)
- - - - animal
      - carbon rich compound
      - vegetable
  - - - Inhibit corrosion
      - Increase abrasion resistance/toughness
      - Protect binder from UV radiation
      - Improve coating adhesion
      - Produce desired color/opacity
      - Examples:
        
        Zinc phosphate, ZnPO₃
        
        Phosphates
        
        Sodium chromate, Na₂CrO₄
    - - Control viscosity during application
      - Examples: toluene, xylene, alcohols, ethers, esters, water
      - Keep binder in solution during storage
      - Determine:
        
        Application flow
        
        Drying time
        
        Flash point
    - - Common Binder Types:
        
        Thermosetting resins:
        
        Epoxy: excellent acid/alkali resistance, adhesion, used as primer
        
        Polyurethane: UV & abrasion resistant, used in aircraft, cars
        
        Thermoplastic resins:
        
        Acrylics: UV stable, color stability, used on car exteriors
        
        Vinyl (PVC): highly impermeable, water and resistant, sprayed on steel in water
      - Types:
        
        Evaporation-based (thermoplastic)
        
        Polymerization (mixing resin + hardener)
        
        Oxygen-reactive (thermosetting)
      - Organic liquid (oil or resins)
        
        Forms dense & tight protective film
      - Functions:
        
        Abrasion, chemical resistance
        
        Anti-corrosive properties
        
        Cohesion & flexibility
        
        Control permeability & hardness
        
        Adherence to substrate
        
        Bind pigments
    - - Small amounts controlling:
        
        Anti-skinning
        
        Settling and sagging agents
        
        Wetting agents
        
        Storage agents
        
        Drying/curing speed
- - - - Types:
        
        (ii) Phosphate Conversion Coating (PCC)
        
        Description:
        
        Sometimes applied on cadmium, tin, aluminium and zinc
        
        Forms thick porous phosphate crystal layer tightly bonded to steel
        
        Applied to cast iron, low-alloy steel and carbon steel
        
        Less harmful to environment than chromate coatings
        
        Used in:
        
        Automotive component (clutch, engine)
        
        (iii) Oxidation Coatings
        
        Description:
        Done through electrochemical reactions, heat or chemicals
        
        Used in
        
        Automotive components
        
        Screws and small fittings
        
        Metal hardware and alloy parts
        
        Advantages:
        
        Low temperature treatment
        
        Low friction surfaces
        
        Cheap and simple to perform
        
        Anodizing
        
        Multiple colours possible
        
        Improved corrosion, abrasion, wear resistance
        
        Suitable for aluminium, magnesium, titanium
        
        Provides excellent surface for painting and adhesive bonding
        
        Electrochemical oxidation (anodic coating)
        
        Disadvantages:
        
        Thin treated layer
        
        Poor durability
        
        Restricted range of materials can be treated
        
        Difficult to control treatment quality on heterogeneous materials
        
        Black Oxide Coating
        
        Mild corrosion resistance
        
        Matte black, low reflection, low cost
        
        Reacts with iron to form Fe₃O₄ (magnetite)
        
        Often oil or wax post dip
        
        • Applied to steel, copper, stainless steel
        
        (i) Chromate Conversion Coating (CCC)
        
        Description:
        
        Immersion in acidic chromate solution (or spray/brush)
        
        Colour varies with base alloy (gold/yellow, dull gold, brown/black)
        
        For aluminium, magnesium, cadmium, zinc alloys
        
        Used in:
        
        Hinges
        
        Household hardware items
        
        Screws
      - Description:
        
        Produced by chemical/electrochemical treatment of the metal surface
        
        Converts part of the metal surface into a protective layer
    - - Description:
        
        Excellent heat resistance and water repellency
        
        Properties depend on the amount of silicone resin and the type of modifying agents (alkyd, acrylic, etc.)
        
        Semi-inorganic silicone-based coatings
      - Used in:
        
        Stakes
        
        Compacted or hard rocky soil
        
        High-heat applications
    - - Advantages:
        
        Strong chemical bonding → durable
        
        Easy to clean
        
        Low friction surface and anti-galling properties
        
        Abrasion & erosion resistant
        
        Protect surface without damaging paint
        
        Long life, heat barrier, insulating, cost-effective
      - Disadvantages:
        
        Application takes time (3 days+)
        
        Requires professional work
        
        High price
      - Description:
        
        Types: Aluminium oxide, Alumina-titania, Chrome-oxide, Zirconium oxide
        
        Resist: Sliding wear, erosion, abrasion, galling, hot gases, corrosive liquids
        
        Forms chemical bonding with paint
        
        Liquid polymer applied by hand to exterior surfaces
        
        Used in:
        
        Ceramic coated tip for welding machine
        
        Ceramic coated pump sleeve
        
        Ceramic coated wheel for printing device
    - - Description:
        
        Fused to metal substrate by heating (425–1000°C)
        
        Typically coated for steels, cast iron and aluminium
        
        Glassy inorganic coating consisting of various metal oxides
        
        To prevent corrosion and enhance beauty
      - Used in:
        
        Chemical processing equipment
        
        Cookware
        
        Plumbing fixtures
        
        Jewelry
        
        Household appliances
        
        Jet-engine components