Question: Tin is widely used in eletrolytic baths for which process that forms a metal coating?
Context: Chromate conversion coating is a type of conversion coating used to passivate steel, aluminum, zinc, cadmium, copper, silver, magnesium, and tin alloys.  It is primarily used as a corrosion inhibitor, primer, decorative finish, or to retain electrical conductivity.  The process is named after the chromate found in chromic acid, also known as hexavalent chromium, the chemical most widely used in the immersion bath process whereby the coating is applied.  However, hexavalent chromium is toxic, thus, highly regulated, so new, non-hexavalent chromium-based processes are becoming more readily available at a commercial level.  One alternative contains trivalent chromium.  In Europe the RoHS (Restriction of Hazardous Substances) Directive is commonly referred to regarding elimination of hexavalent chromium in electrical and electronic equipment, and the REACH ("Registration, Evaluation, Authorisation and Restriction of Chemicals") Directive to wider applications including chromate conversion coating processes, paint primers and other preparations. Electroplating is a process that uses electric current to reduce dissolved metal cations so that they form a thin coherent metal coating on an electrode.  The term is also used for electrical oxidation of anions onto a solid substrate, as in the formation silver chloride on silver wire to make silver/silver-chloride electrodes.  Electroplating is primarily used to change the surface properties of an object (such as abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities), but may also be used to build up thickness on undersized parts or to form objects by electroforming. Fusion bonded epoxy coating, also known as fusion-bond epoxy powder coating and commonly referred to as FBE coating, is an epoxy-based powder coating that is widely used to protect steel pipe used in pipeline construction, concrete reinforcing bars (rebar) and on a wide variety of piping connections, valves etc. from corrosion.  FBE coatings are thermoset polymer coatings.  They come under the category of "protective coatings" in paints and coating nomenclature.  The name "fusion-bond epoxy" is due to resin cross-linking and the application method, which is different from a conventional paint.  The resin and hardener components in the dry powder FBE stock remain unreacted at normal storage conditions.  At typical coating application temperatures, usually in the range of 180 to , the contents of the powder melt and transform to a liquid form.  The liquid FBE film wets and flows onto the steel surface on which it is applied, and soon becomes a solid coating by chemical cross-linking, assisted by heat.  This process is known as “fusion bonding”.  The chemical cross-linking reaction taking place in this case is irreversible.  Once the curing takes place, the coating cannot be returned to its original form by any means.  Application of further heating will not “melt” the coating and thus it is known as a “thermoset” coating.  The world's leading FBE manufacturers are Valspar, SolEpoxy (former Henkel/Dexter), KCC Corporation, Jotun Powder Coatings, Sherwin-Williams, 3M, Axalta Coating Systems, Akzo Nobel, BASF, Manifa Paints and Powder Coatings and Rohm & Haas. Electric resistance welding (ERW) refers to a group of welding processes such as spot and seam welding that produce coalescence of faying surfaces where heat to form the weld is generated by the electrical resistance of material combined with the time and the force used to hold the materials together during welding.  Some factors influencing heat or welding temperatures are the proportions of the workpieces, the metal coating or the lack of coating, the electrode materials, electrode geometry, electrode pressing force, electrical current and length of welding time.  Small pools of molten metal are formed at the point of most electrical resistance (the connecting or "faying" surfaces) as an electrical current (100–100,000 A) is passed through the metal.  In general, resistance welding methods are efficient and cause little pollution, but their applications are limited to relatively thin materials and the equipment cost can be high (although in production situations the cost per weld may be low). Cadmium chromate is the inorganic compound with the formula CdCrO.  It is relevant to chromate conversion coating, which is used to passivate common metal alloys such as aluminum, zinc, cadmium, copper, silver, magnesium, and tin.  In conversion coating chromate reacts with these metals to prevent corrosion, retain electrical conductivity, and provide a finish for the appearance of the final alloy products.  This process is commonly used on hardware and tool items.  Chromate species take on their distinctive yellow color when coated. Bathtub refinishing also known as bathtub resurfacing, bathtub reglazing or bathtub re-enameling is the process of refreshing the surface of a worn, damaged bathtub to a like-new condition.  This process typically involves repairing any damaged areas.  Chips or cracks are repaired using Bondo or another type of polyester putty.  After repairs are made the surface is prepped with an acid etching.  Etching provides mechanical adhesion.  Porcelain, enamel, and fiberglass tubs are non-porous and do not provide a good substrate for the new coating to attach to.  Etching the surface provides a porous surface that will allow proper adhesion.  Another possible method is to apply an adhesion-promoting bonding agent like silane to the surface before applying the coating.  The two methods can be used in unison or independently.  The greatest adhesion is achieved by using both methods together.  Some new refinishing processes do not require the use of etching, by relying on silane alone.  After preparing the surface, primer is applied, followed by a top coat.  Generally, a catalyzed two-component cross-link synthetic white coating is applied, but the coating does not have the durability or abrasive tolerance of the original glass-enamel coating of a factory-new bathtub. Plasma transferred wire arc (PTWA) thermal spraying is a thermal spraying process that deposits a coating on the internal surface of a cylindrical surface, or external surface of any geometry.  It is predominantly known for its use in coating the cylinder bores of an engine, enabling the use of aluminum engine blocks without the need for heavy cast iron sleeves.  A single conductive wire is used as "feedstock" for the system.  A supersonic plasma jet melts the wire, atomizes it and propels it onto the substrate.  The plasma jet is formed by a transferred arc between a non-consumable cathode and the wire.  After atomization, forced gas transports the stream of molten droplets onto the bore wall.  The particles flatten when they impinge on the surface of the substrate, due to their high kinetic energy.  The particles rapidly solidify upon contact and can form both crystalline and amorphus phases.  There is also the possibility to produce multi-layer coatings.  The stacked particles make up a highly wear-resistant coating.  All conductive wires up to and including 0.0625" (1.6mm) can be used as feedstock material, including "cored" wires.  PTWA can be used to apply a coating to the wear surface of engine or transmission components to replace a bushing or bearing.  For example, using PTWA to coat the bearing surface of a connecting rod offers a number of benefits including reductions in weight, cost, friction potential, and stress in the connecting rod. Micromy is a hard surface coating company based in Täby, Sweden.  The company specializes in applying hard coating to a wide range of substrate materials using a PVD process (Physical vapor deposition).  Depending on the application, different coating film materials can be produced, such as TiN (Titanium nitride), TiC, TiNC (grey, antracite, black), AlTiN (violet, black) or DLC (Diamond-Like Carbon).  The coating is mainly used for industrial applications based on the different properties of the materials.  However, the PVD process results in a finish such that many coatings are equally suitable for decorative purposes. Tin(II) chloride, also known as stannous chloride, is a white crystalline solid with the formula Sn Cl .  It forms a stable dihydrate, but aqueous solutions tend to undergo hydrolysis, particularly if hot.  SnCl is widely used as a reducing agent (in acid solution), and in electrolytic baths for tin-plating.  Tin(II) chloride should not be confused with the other chloride of tin; tin(IV) chloride or stannic chloride (SnCl). Microencapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules, of many useful properties.  In general, it is used to incorporate food ingredients, enzymes, cells or other materials on a micro metric scale.  Microencapsulation can also be used to enclose solids, liquids, or gases inside a micrometric wall made of hard or soft soluble film, in order to reduce dosing frequency and prevent the degradation of pharmaceuticals.  In a relatively simple form, a microcapsule is a small sphere with a uniform wall around it.  The material inside the microcapsule is referred to as the core, internal phase, or fill, whereas the wall is sometimes called a shell, coating, or membrane.  Some materials like lipids and polymers, such as alginate, may be used as a mixture to trap the material of interest inside.  Most microcapsules have pores with diameters between a few micrometers and a few millimeters.  The coating materials generally used for coating are:
Answer: Electroplating