Types of Coating
Metallic Coating
Organic Coating
Contains metallic element or alloy
Ground metal floats on non-toxic water based acrylic binder
Often made from polymer , eg :epoxy
Applied by using either chemically, electrochemically,mechanically or sprayer
Can be applied on metal & non-metal surfaces
Advantages and Applications of Metallic Coating
Durable and corrosion resistance
Corrosion resistance depends on choice of metal for coating and thickness
Minizmize friction by acting as lubricant for structural components
Non-stick properties makes it easy to be cleaned
Suitable for outdoor equipments such as boats
Compounds rich in carbon
Have organic binders such as epoxy
Organic coating are polymers&epoxy
Applied on liquid form,sometimes powder form
Organic binders provides coating properties
Dyes/pigments gives colour for coating
Advantages& Applications of Organic Coatings
A dense&tight protective layer of organic liquid
Binders are hardens by 2 method which is reacting with O2 or with evaporation
Binders are 2 types which is
Abrasion resistance
Corrosion resistance properties
Adherence to substrate
Dyes gives desired colour for coating
Coatings have resistance to UV
Solvents provides fluidity during application and also determines drying time
Additives are found in small amount of solid/liquid that controls speed of drying
Low in cost
Act as barrier for diffusion of aggressive chemicals
Inorganic Coating
Inorganic binders such as silicates
There are different types of Inorganic Coatings
Low temperature treatment
Cheap and cost-effective
Ceramic Coatings
Conversion Coatings
Inorganic zincs/silicates
Porcelain Enamels
Low friction surface
Organic ceramics coating are divided into 4 components
Binders
Dyes/Pigments
Solvents
Additives
Structural Metallic coating techniques
Hot-dip galvanising
Thermal Spraying
Non-structural Metallic coating techniques
Electroplating
Gas Galvanising
Advantages and Applications of Inorganic Coatings
Ceramic Coatings
A clear coat of liquid polymer
Examples are aliminium oxide and chrome-oxide
Polymer bonds with factory paint
High hardness and durability
Low friction and resistance to abrasion and corrosion
Resistance to corrosion
Expensive
Very long application time
Conversion coatings
Chemical/Electrochemical coating on metallic surface
Chromate conversion coatings (CCC)
Very thin film, 2.5 micron
Short time immersion in acid chromate solution
Protect hardware items
Phosphate conversion coatings (PCC)
Less harmful to environment than CCC
Prevents rust under the layer of paint
Applied by brushing, spraying or prolonged immersion in acid
Oxidations
Electrochemical reactions
Offer a matte black appearance
Suitable for steel,copper and stainless steel
Anodizing
Multiple colour possible
Thick film coating
Suitable for aluminium
Inorganic zinc/silicates
Metallic zinc coatings suspended on hard silicate matrix , its application are suitable under water such as for marine. It has poor resistance to acid&alkali but high for salt, moisture and solvent
Weather and superior corrosion resistance
Silicon coating has outstanding heat resistance and it is hydrophobic. It makes suitable for high heat applications
Porcelain Enamel
Fuses with thin layer of glass with metal
Prevent corrosion&enhance beauty
Resistance to acid,alkali&solvent
Thermoset resins
Thermoplastic resins
Epoxy
Poly-urethanes
Vinyls