Spraying lacquer on cabinets LCCN2016850642

A coating is a covering that is applied to the surface of an object, or substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as

liquid Liquid is a state of matter with a definite volume but no fixed shape. Liquids adapt to the shape of their container and are nearly incompressible, maintaining their volume even under pressure. The density of a liquid is usually close to th ...

s, gases or

solid Solid is a state of matter where molecules are closely packed and can not slide past each other. Solids resist compression, expansion, or external forces that would alter its shape, with the degree to which they are resisted dependent upon the ...

s e.g.

powder coating Powder coating is a type of coating that is applied as a free-flowing, dry powder. Unlike conventional liquid paint, which is delivered via an evaporating solvent, powder coating is typically applied electrostatically and then Powder coating#Curin ...

s. Paints and

lacquer Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity. Asian lacquerware, which may be c ...

s are coatings that mostly have dual uses, which are protecting the substrate and being decorative, although some artists paints are only for decoration, and the paint on large industrial pipes is for identification (e.g. blue for process water, red for fire-fighting control) in addition to preventing corrosion. Along with corrosion resistance, functional coatings may also be applied to change the surface properties of the substrate, such as adhesion, wettability, or wear resistance.Howarth G.A "Synthesis of a legislation compliant corrosion protection coating system based on urethane, oxazolidine and waterborne epoxy technology" Master of Science Thesis April 1997 Imperial College London In other cases the coating adds a completely new property, such as a magnetic response or electrical conductivity (as in semiconductor device fabrication, where the substrate is a wafer), and forms an essential part of the finished product. A major consideration for most coating processes is controlling coating thickness. Methods of achieving this range from a simple brush to expensive precision machinery in the electronics industry. Limiting coating area is crucial in some applications, such as

printing Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The ...

. "Roll-to-roll" or "web-based" coating is the process of applying a thin film of functional material to a substrate on a roll, such as paper,

fabric Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, and different types of fabric. At first, the word "textiles" only referred to woven fabrics. However, weaving is no ...

, film, foil, or sheet stock. This continuous process is highly efficient for producing large volumes of coated materials, which are essential in various industries including printing, packaging, and electronics. The technology allows for consistent high-quality application of the coating material over large surface areas, enhancing productivity and uniformity.

Applications

Coatings can be both decorative and have other functions. A pipe carrying water for a fire suppression system can be coated with a red (for identification) anticorrosion paint. Most coatings to some extent protect the substrate, such as maintenance coatings for metals and concrete. A decorative coating can offer a particular reflective property, such as high gloss, satin, matte, or flat appearance. A major coating application is to protect metal from corrosion. Automotive coatings are used to enhance the appearance and durability of vehicles. These include primers, basecoats, and clearcoats, primarily applied with spray guns and electrostatically. The body and underbody of automobiles receive some form of underbody coating. Such anticorrosion coatings may use

graphene Graphene () is a carbon allotrope consisting of a Single-layer materials, single layer of atoms arranged in a hexagonal lattice, honeycomb planar nanostructure. The name "graphene" is derived from "graphite" and the suffix -ene, indicating ...

in combination with water-based epoxies. Coatings are used to seal the surface of concrete, such as seamless polymer/resin flooring, bund wall/containment lining,

waterproofing Waterproofing is the process of making an object, person or structure waterproof or water-resistant so that it remains relatively unaffected by water or resists the ingress of water under specified conditions. Such items may be used in wet env ...

and damp proofing concrete walls, and

bridge deck A deck is the surface of a bridge. A structural element of its superstructure A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildin ...

s. Compare with tradition coatings, moisture curing polyurethane has been widely used because of the excellent adaptability and ease of construction. The mechanical properties could be enhanced by introducing multiple hydrogen bonds and optimize the microphase separation structure. Most

roof coating A roof coating is a monolithic, fully adhered, fluid applied roofing membrane. Many roof coatings are Elastomer, elastomeric, that is, they have elastic properties that allow them to stretch and return to their original shape without damage. Typi ...

s are designed primarily for waterproofing, though sun reflection (to reduce heating and cooling) may also be a consideration. They tend to be

elastomeric An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus (E) and high failure strain compared with other materials. The term, a portmanteau of ''elas ...

to allow for movement of the roof without cracking within the coating membrane. Wood has been a key material in construction since ancient times, so its preservation by coating has received much attention. Efforts to improve the performance of wood coatings continue. Coatings are used to alter

tribological Tribology is the science and engineering of understanding friction, lubrication and wear phenomena for interacting surfaces in relative motion. It is highly interdisciplinary, drawing on many academic fields, including physics, chemistry, material ...

properties and wear characteristics. These include anti-friction, wear and scuffing resistance coatings for

rolling-element bearings In mechanical engineering, a rolling-element bearing, also known as a rolling bearing,ISO 15 is a bearing which carries a load by placing rolling elements (such as balls, cylinders, or cones) between two concentric, grooved rings called race ...

Other

Other functions of coatings include: *

Anti-fouling Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that ...

coatings *

Anti-microbial An antimicrobial is an agent that kills microorganisms (microbicide) or stops their growth (bacteriostatic agent). Antimicrobial medicines can be grouped according to the microorganisms they are used to treat. For example, antibiotics are used aga ...

coatings. *

Anti-reflective coating An antireflective, antiglare or anti-reflection (AR) coating is a type of optical coating applied to the surface of lens (optics), lenses, other optical elements, and photovoltaic cells to reduce reflection (physics), reflection. In typical ima ...

s for example on spectacles. * Coatings that alter or have magnetic, electrical or electronic properties. *

Flame retardant Flame retardants are a diverse group of chemicals that are added to manufactured materials, such as plastics and textiles, and surface finishes and coatings. Flame retardants are activated by the presence of an combustion, ignition source and pr ...

coatings. Flame-retardant materials and coatings are being developed that are

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

and bio-based. These include coatings with

intumescent An intumescent substance is one that swells as a result of heat exposure, leading to an increase in volume and decrease in density. Intumescence refers to the process of swelling. Intumescent materials are typically used in passive fire protectio ...

functionality. *

Non-stick A non-stick surface is engineered to reduce the ability of other materials to stick to it. Non-sticking cookware is a common application, where the non-stick coating allows food to brown without sticking to the pan. Non-stick is often used to ref ...

PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off fro ...

coated cooking pots/pans. *

Optical coating An optical coating is one or more thin-film optics, thin layers of material deposited on an optical component such as a lens (optics), lens, prism (optics), prism or mirror, which alters the way in which the optic reflection (physics), reflects a ...

s are available that alter optical properties of a material or object. *

UV coating A UV coating (or more generally a radiation cured coating) is a surface treatment which either is cured by ultraviolet radiation, or which protects the underlying material from such radiation's harmful effects. They have come to the fore because ...

Analysis and characterization

Numerous destructive and non-destructive evaluation (NDE) methods exist for characterizing coatings. The most common destructive method is

microscopy Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical mic ...

of a mounted

cross-section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture and engineering 3D * Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) ...

of the coating and its substrate. The most common non-destructive techniques include ultrasonic thickness measurement,

X-ray fluorescence X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by being bombarded with high-energy X-rays or gamma rays. The phenomenon is widely used for elemental analysis ...

(XRF),

X-Ray diffraction X-ray diffraction is a generic term for phenomena associated with changes in the direction of X-ray beams due to interactions with the electrons around atoms. It occurs due to elastic scattering, when there is no change in the energy of the waves. ...

(XRD), photothermal coating thickness measurement and micro hardness indentation.

X-ray photoelectron spectroscopy X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique that measures the very topmost 50-60 atoms, 5-10 nm of any surface. It belongs to the family of photoemission spectroscopies in which electro ...

(XPS) is also a classical characterization method to investigate the chemical composition of the nanometer thick surface layer of a material.

Scanning electron microscopy A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that ...

coupled with energy dispersive X-ray spectrometry ( SEM-EDX, or SEM-EDS) allows to visualize the surface texture and to probe its elementary chemical composition. Other characterization methods include

transmission electron microscopy Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a g ...

(TEM),

atomic force microscopy Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the opti ...

(AFM),

scanning tunneling microscope A scanning tunneling microscope (STM) is a type of scanning probe microscope used for imaging surfaces at the atomic level. Its development in 1981 earned its inventors, Gerd Binnig and Heinrich Rohrer, then at IBM Zürich, the Nobel Prize in ...

(STM), and Rutherford backscattering spectrometry (RBS). Various methods of

Chromatography In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it ...

are also used, as well as thermogravimetric analysis.

Formulation

The

formulation Formulation is a term used in various senses in various applications, both the material and the abstract or formal. Its fundamental meaning is the putting together of components in appropriate relationships or structures, according to a formula ...

of a coating depends primarily on the function required of the coating and also on aesthetics required such as color and gloss. The four primary ingredients are the

resin A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...

(or binder),

solvent A solvent (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a Solution (chemistry), solution. A solvent is usually a liquid but can also be a solid, a gas ...

which may be water (or solventless),

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

(s) and additives. Research is ongoing to remove

heavy metals upright=1.2, Crystals of lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals is a controversial and ambiguous term for metallic elements with relatively h ...

from coating formulations completely. For example, on the basis of experimental and epidemiological evidence, it has been classified by the IARC (International Agency for Research on Cancer) as a human carcinogen by inhalation (class I)
ISPESL
2008).

Processes

Coating processes may be classified as follows:

Vapor deposition

Chemical vapor deposition

Metalorganic vapour phase epitaxy Metalorganic vapour-phase epitaxy (MOVPE), also known as organometallic vapour-phase epitaxy (OMVPE) or metalorganic chemical vapour deposition (MOCVD), is a chemical vapour deposition method used to produce single- or polycrystalline thin films. ...

* Electrostatic spray assisted vapour deposition (ESAVD) *

Sherardizing Sherardising or Zinc thermal diffusion is a process of galvanization of ferrous metal surfaces, also called vapour galvanising and dry galvanizing. The process is named after British metallurgist Sherard Osborn Cowper-Coles (son of naval inventor ...

* Some forms of

Epitaxy Epitaxy (prefix ''epi-'' means "on top of”) is a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline seed layer. The deposited cry ...

Molecular beam epitaxy Molecular-beam epitaxy (MBE) is an epitaxy method for thin-film deposition of single crystals. MBE is widely used in the manufacture of semiconductor devices, including transistors. MBE is used to make diodes and MOSFETs (MOS field-effect transis ...

Physical vapor deposition

Cathodic arc deposition {{Short description, Type of physical vapor deposition technique Cathodic arc deposition or Arc-PVD is a physical vapor deposition technique in which an electric arc is used to vaporize material from a cathode target. The vaporized material then co ...

* Electron beam physical vapor deposition (EBPVD) * Ion plating * Ion beam assisted deposition (IBAD) * Magnetron sputtering *

Pulsed laser deposition Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique where a high-power pulsed laser beam is focused inside a vacuum chamber to strike a target of the material that is to be deposited. This material is vaporized from the ...

* Sputter deposition * Vacuum deposition * Vacuum evaporation, evaporation (deposition) * Pulsed electron deposition (PED)

Chemical and electrochemical techniques

* Conversion coating ** Autophoretic, the registered trade name of a proprietary series of auto-depositing coatings specifically for ferrous metal substrates ** Anodising **

Chromate conversion coating Chromate conversion coating or alodine coating is a type of conversion coating used to passivate steel, aluminium, zinc, cadmium, copper, silver, titanium, magnesium, and tin alloys. The coating serves as a corrosion inhibitor, as a pri ...

Plasma electrolytic oxidation Plasma electrolytic oxidation (PEO), also known as electrolytic plasma oxidation (EPO) or microarc oxidation (MAO), is an electrochemical surface treatment process for generating oxide coatings on metals. It is similar to anodizing, but it employ ...

** Phosphate (coating) * Ion beam mixing * Pickled and oiled, a type of plate

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

coating *

Plating Plating is a finishing process in which a metal is deposited on a surface. Plating has been done for hundreds of years; it is also critical for modern technology. Plating is used to decorate objects, for corrosion inhibition, to improve solderab ...

** Electroless plating ** nickel plating coating using a different material to preserve mechanical properties **

Electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric cur ...

Spraying

Spray painting Spray painting is a painting technique in which a device sprays coating material (paint, ink, varnish, etc.) through the air onto a surface. The most common types employ compressed gas—usually air compressor, air—to atomize and direct the pa ...

* High velocity oxygen fuel (HVOF) * Plasma spraying *

Thermal spray Thermal spraying techniques are coating processes in which melted (or heated) materials are sprayed onto a surface. The "feedstock" (coating precursor) is heated by electrical (plasma or arc) or chemical means (combustion flame). Thermal sprayi ...

ing * Kinetic metallization (KM) * Plasma transferred wire arc thermal spraying * The common forms of

Powder coating Powder coating is a type of coating that is applied as a free-flowing, dry powder. Unlike conventional liquid paint, which is delivered via an evaporating solvent, powder coating is typically applied electrostatically and then Powder coating#Curin ...

Roll-to-roll coating processes

Common

roll-to-roll In the field of electronic devices, roll-to-roll processing, also known as web processing, reel-to-reel processing or R2R, is the process of creating electronic devices on a roll of flexible plastic, metal foil, or flexible glass. In other fields ...

coating processes include: *

Air knife An air knife is a tool used to blow off liquid or debris from products as they travel on conveyors. Air knives are normally used in manufacturing or as the first step in a recursive recycling process to separate lighter or smaller particles fro ...

coating *

Anilox In printing, anilox is a method used to provide a measured amount of ink to a flexography, flexographic (flexo) printing plate. An anilox roll is a hard cylinder (geometry), cylinder, usually constructed of a steel or aluminum core which is coate ...

coater * Flexo coater * Gap Coating ** Knife-over-roll coating * Gravure coating * Hot melt coating- when the necessary coating viscosity is achieved by temperature rather than solution of the polymers etc. This method commonly implies slot-die coating above room temperature, but it also is possible to have hot-melt roller coating; hot-melt metering-rod coating, etc. * Immersion

dip coating Dip coating is an industrial coating process which is used, for example, to manufacture bulk products such as coated fabrics and condoms and specialised coatings for example in the biomedical field. Dip coating is also commonly used in academic ...

* Kiss coating * Metering rod (Meyer bar) coating * Roller coating ** Forward roller coating ** Reverse roll coating * Silk Screen coater ** Rotary screen * Slot Die coating - Slot die coating was originally developed in the 1950s. Slot die coating has a low operational cost and is an easily scaled processing technique for depositing thin and uniform films rapidly, while minimizing material waste. Slot die coating technology is used to deposit a variety of liquid chemistries onto substrates of various materials such as

glass Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...

metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...

, and

polymer A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their br ...

s by precisely metering the process

fluid In physics, a fluid is a liquid, gas, or other material that may continuously motion, move and Deformation (physics), deform (''flow'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are M ...

and dispensing it at a controlled rate while the coating die is precisely moved relative to the substrate. The complex inner geometry of conventional slot dies require

machining Machining is a manufacturing process where a desired shape or part is created using the controlled removal of material, most often metal, from a larger piece of raw material by cutting. Machining is a form of subtractive manufacturing, which util ...

or can be accomplished with 3-D printing. * Extrusion coating - generally high pressure, often high temperature, and with the web travelling much faster than the speed of the extruded polymer ** Curtain coating- low viscosity, with the slot vertically above the web and a gap between slot-die and web. ** Slide coating- bead coating with an angled slide between the slot-die and the bead. Commonly used for multilayer coating in the photographic industry. ** Slot die bead coating- typically with the web backed by a roller and a very small gap between slot-die and web. ** Tensioned-web slot-die coating- with no backing for the web. *

Inkjet Inkjet printing is a type of printer (computing), computer printing that recreates a digital image by propelling droplets of ink onto paper or plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range f ...

printing *

Lithography Lithography () is a planographic method of printing originally based on the miscibility, immiscibility of oil and water. The printing is from a stone (lithographic limestone) or a metal plate with a smooth surface. It was invented in 1796 by ...

Flexography Flexography (often abbreviated to flexo) is a form of printing process which utilizes a flexible Relief print, relief plate. It is essentially a modern version of letterpress, evolved with high speed rotary functionality, which can be used for ...

Physical

* Langmuir-Blodgett * Spin coating *

Dip coating Dip coating is an industrial coating process which is used, for example, to manufacture bulk products such as coated fabrics and condoms and specialised coatings for example in the biomedical field. Dip coating is also commonly used in academic ...