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 liquids, gases or solids e.g. powder coatings. Paints and lacquers 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. "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, 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 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 and damp proofing concrete walls, and bridge decks. 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 coatings are designed primarily for waterproofing, though sun reflection (to reduce heating and cooling) may also be a consideration. They tend to be elastomeric 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 properties and wear characteristics. These include anti-friction, wear and scuffing resistance coatings for rolling-element bearings

Other

Other functions of coatings include: * Anti-fouling coatings * Anti-microbial coatings. * Anti-reflective coatings for example on spectacles. * Coatings that alter or have magnetic, electrical or electronic properties. * Flame retardant coatings. Flame-retardant materials and coatings are being developed that are phosphorus and bio-based. These include coatings with intumescent 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 coated cooking pots/pans. * Optical coatings are available that alter optical properties of a material or object. * UV coatings

Analysis and characterization

Numerous destructive and non-destructive evaluation (NDE) methods exist for characterizing coatings. The most common destructive method is microscopy of a mounted cross-section of the coating and its substrate. The most common non-destructive techniques include ultrasonic thickness measurement, X-ray fluorescence (XRF), X-Ray diffraction (XRD), photothermal coating thickness measurement and micro hardness indentation. X-ray photoelectron spectroscopy (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 (TEM), atomic force microscopy (AFM), scanning tunneling microscope (STM), and Rutherford backscattering spectrometry (RBS). Various methods of Chromatography are also used, as well as thermogravimetric analysis.

Formulation

The formulation 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 (or binder), solvent which may be water (or solventless), pigment(s) and additives. Research is ongoing to remove heavy metals 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 * Electrostatic spray assisted vapour deposition (ESAVD) * Sherardizing * Some forms of Epitaxy ** Molecular beam epitaxy

Physical vapor deposition

* Cathodic arc deposition * Electron beam physical vapor deposition (EBPVD) * Ion plating * Ion beam assisted deposition (IBAD) * Magnetron sputtering * Pulsed laser deposition * 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 ** Plasma electrolytic oxidation ** 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 ** 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 spraying * Kinetic metallization (KM) * Plasma transferred wire arc thermal spraying * The common forms of Powder coating

Roll-to-roll coating processes

Common roll-to-roll coating processes include: * Air knife coating * Anilox 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 * 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,

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 polymers 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 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 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

Physical

* Langmuir-Blodgett * Spin coating * Dip coating