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94 GLOSSARY Abrasive A material used for wearing away a surface by rubbing; a fine, granulated material used for blast cleaning. Abrasive particles of controlled mesh sizes are propelled by compressed air, water, or centrifugal force to clean and roughen a surface. Blast-cleaning abrasives often are simply referred to as metallic or nonmetallic and as shot- or grit-like. Acceptance Testing The purchaser's testing of received products to determine that the quality of manufactured products meets specified requirements. Adhesion The degree of attraction between a coating and a substrate or between two coats of paint that are held together by chemical or mechanical forces or both. Adhesion often is called the "bonding strength" of a coating. Adhesion should not be confused with "cohesion," which is the internal force holding a single coating together. Air Contaminant Any substance of either artificial or natural origin in the ambient air, such as particulates (dust, fly ash, smoke, etc.), mists (other than water), fumes (gases), etc. Aliphatic Solvents Hydrocarbon solvents compounded primarily of paraffinic and cyclo-paraffinic (naphthenic) hydrocarbon compounds. Aromatic hydrocarbon content may range from less than 1% to about 35%. Alkyd Resins Synthetic resins formed by the condensation of polyhydric alcohols with polybasic acids. They may be regarded as complex esters. The most common polybasic alcohol used is glycerol, and the most common polybasic acid is phthalic anhydride. Alternate Immersion An exposure in which a surface is in frequent, perhaps fairly long, immersion in either freshwater or saltwater alternated with exposure to the atmosphere above the water. Ambient Air Quality Average atmospheric purity, as distinguished from discharge measurements taken at the source of pollution. The general amount of pollution present in a broad area. Anchor Pattern See Profile. Aromatic Solvents Hydrocarbon solvents composed wholly or primarily of aromatic hydrocarbon compounds. Aromatic solvents containing less than 80% aromatic compounds are frequently designated as partially aromatic solvents.

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95 Atomization The mechanical subdivision of a bulk liquid or meltable solid, such as certain metals, to produce droplets, which vary in diameter (depending on the process) from under 10 to over 100 m. Bend Test (Also flexibility test) Test applied to cured films to determine if they are able to elongate without fracture or debonding. Blasting Cleaning materials using a blast of air that directs small abrasive, angular particles against the surface. Blistering Formation of dome-shaped projections in coatings resulting from local loss of adhesion and lifting of the film from an underlying paint film or the base substrate. Bond Strength The force required to pull a coating free of a substrate, usually expressed in kPa (psi). Brackish Water Water with salinity between 0.5 and 17 parts per thousand. Cathodic Protection A technique to reduce the corrosion rate of a metal surface by making it a cathode of an electrochemical cell. Centrifugal Blast Cleaning Use of motor-driven bladed wheels to hurl abrasive at a surface by centrifugal force. Chalking Formation of a friable powder on the surface of a coating caused by the disintegration of the binding medium due to disruptive factors during weathering. Checking That phenomenon manifested in paint films by slight breaks in the film that do not penetrate to the underlying surface. The break is a "crack" if the underlying surface is visible. Coating System The applied and cured multilayer film or the components of a system based on non-paint type coating. Corrosion The deterioration of a metal by chemical or electrochemical reaction resulting from exposure to weathering, moisture, chemicals, or other agents in the environment in which it is placed. Cracking The splitting of a dry paint film, usually as the result of aging. Crevice Corrosion Corrosion that occurs within or adjacent to a crevice formed by contact with another piece of the same or another metal or with a nonmetallic material. Deposition Efficiency The ratio (usually expressed as a percentage) of the weight of spray deposit on the substrate to the total weight of the material sprayed.

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96 Deposition Rate The weight of material deposited per unit of time. Dew Point The temperature at which water vapor present in the atmosphere is just sufficient to saturate it. When air is cooled below the dew point, the excess water vapor appears as tiny water droplets or crystals of ice, depending on the temperature of the air mass. DFT Dry film thickness. Edge Effect Loosening of the adhesive bond between a sprayed deposit and the substrate at the workpiece edges. Electrode A component for the electrical circuit through which current is conducted to the arc. Epoxy Resin Cross-linking resins based on the reactivity of the epoxide group. Flame Spray Any process whereby a material is brought to its melting point and sprayed onto a surface to produce a coating. The process includes metallizing, thermospray, and plasma flame. Flash Point The lowest temperature of a liquid at which it gives off sufficient vapor to form an ignitable mixture with the air near the surface of the liquid or within the vessel used. Flash Rusting Rusting that occurs on metal within minutes to a few hours after blast cleaning or other cleaning is completed. The speed with which flash rusting occurs may be indicative of salt contamination on the surface, high humidity, or both. Freshwater Water having salinity less than 0.5 parts per thousand. Galvanic Corrosion Accelerated corrosion of a metal because of an electrical contact with a more noble metal or nonmetallic conductor in a corrosive electrolyte. The term "dissimilar metal corrosion" is sometimes used. Galvanic Protection Reduction or elimination of corrosion of a metal achieved by making current flow to it from a solution by connecting it to a metal that is more active on the electromotive series (galvanic anode). The galvanic anode for steel would be a sacrificial metal, such as zinc, magnesium, or aluminum. Industrial Environment Environments with a large quantity of atmospheric pollutants, including sulfur-containing solids and gases that strengthen the electrolyte film. Corrosion significantly influenced by humidity, time of wetness, and wind direction.

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97 Interface The contact surface between a sprayed deposit and the substrate. Marine Environment An atmospheric exposure that is frequently wetted by salt mist, but which is not in direct contact with salt spray or splashing waves. This environment contains a high concentration of chlorides. Masking Protecting a substrate surface from the effects of blasting or adhesion of a sprayed deposit. Matrix The major continuous substance of a thermally sprayed coating as opposed to inclusions or particles of materials having dissimilar characteristics. Mechanical Bond The adherence of a thermally sprayed deposit to a roughened surface by the mechanism of particle interlocking. Metallizing Spraying a coating of metal onto a surface. See also Thermal Spraying. Nozzle A device that directs a shielding media; a device that provides atomizing air in a wire-arc spray gun; the anode in a plasma gun; the gas burning jet in a rod or flame-wire spray gun. Overspray Atomized paint or sprayed coating particles that deflect from or miss the surface being sprayed; Spray particles that are not molten enough to fuse when they reach the surface being sprayed. As a result, overspray may contaminate property beyond the surface being sprayed. Oxide A chemical compound, the combination of oxygen with a metal forming a ceramic; examples include aluminum oxide and iron oxide. Parameter A measurable factor relating to several variables; loosely used to mean a spraying variable, spraying condition, spray rate, spray distance, angle, gas pressure, gas flow, etc. Particle Size The average diameter of a given powder or grit granule. Pass A single passage of the thermal spray device across the surface of a substrate. Plasma Spraying A thermal spray process in which the coating material is melted with heat from a plasma torch that generates a nontransferred arc; molten powder coating materials are propelled against the base metal by the hot, ionized gas issuing from the torch.

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98 Polyurethant Coating vehicles containing a polyisocyanate monomer reacted in such a manner as to yield polymers containing a ratio, proportion, or combination of urethane linkages; active isocyanate groups; or polyisocyanate monomer. Porosity Small voids, such as in concrete, that allow fluids to penetrate an otherwise impervious material; The ratio is usually expressed as a percentage of the volume of voids in a material to the total volume of the material including the voids. Profile Surface contour of a blast-cleaned or substrate surface viewed from the edge. Psychrometer A test instrument that is used to determine humidity and dew point. Quality Control The system whereby a manufacturer ensures that materials, methods, workmanship, and the final product meet the requirements of a given standard. Replica Tape A specially constructed tape used to measure surface profile. The tape is pressed against the surface, after which the impression created by the profile is measured with a micrometer. Residual Stress Stresses remaining in a structure or member as a result of thermal or mechanical treatment, or both. Resin General term applied to a wide variety of more or less transparent and fusible products, natural or synthetic. Any polymer that is a basic material for coatings and plastics. Rural Environment An atmospheric exposure that is virtually unpolluted by smoke and sulfur gases and that is sufficiently inland to be unaffected by salt contamination or the high humidity of coastal areas. Corrosion depends on temperature, humidity, and moisture retention. Rust The reddish, brittle coating formed on iron or ferrous metals resulting from exposure to a humid atmosphere or chemical attack. Sacrificial Protection The use of a metallic coating to protect steel. In the presence of an electrolyte, such as salt water, a galvanic cell is set up and the metallic coating corrodes instead of the steel. See also Galvanic Protection. Seawater Water having salinity above 17 parts per thousand. Seal Coat Material applied to infiltrate and close the pores of a thermally sprayed deposit.

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99 Silicone One of a class of compounds consisting of polymerizable, high- temperature-resistant resins; lubricant greases, and oils; organic solvent-soluble water repellants; surface tension modifiers for organic solvents; etc. Soluble Salt Contaminant Water-soluble inorganic compounds (such as chlorides and sulfates) that contaminate a product. When soluble salts are present on a prepared steel surface, they may cause premature coating failure. Soluble salt contaminants are sometimes referred to as "ionic contaminants" or "invisible contaminants." Spalling The flaking or separation of a sprayed coating. Spraying Method of application in which the coating material is broken up into a fine mist that is directed onto the surface to be coated. Spray Angle The angle of particle impingement, measured from the surface of the substrate to the axis of the spraying nozzle. Spray Distance The distance maintained between the thermal spraying gun nozzle tip and the surface of the workpiece during spraying. Spray Rate The rate at which surfacing feedstock material passes through the gun. Substrate Basic surface on which a material (e.g., a coating) adheres. Surface Preparation Any method of treating a surface to prepare it for coating. Surface preparation methods include washing with water, detergent solution, or solvent; cleaning using hand or power tools; water washing or jetting without abrasive; or abrasive blast cleaning. Thermally Sprayed The technician or specialist who applies the thermally sprayed Coating Applicator coating. Thermally Sprayed Metal Solid coating materials that are melted (or at least softened) before Coating (TSMC) dispersion (spraying) onto a surface. Thermal Spraying Spraying finely divided particles of powder or droplets of an atomized material for overlay coating of a substrate. Topcoat The last coating material applied in a coating system, specifically formulated for aesthetic and/or environmental resistance. Also referred to as finish coat. Traverse Speed The linear velocity at which the thermal spraying gun traverses across the workpiece during the spraying operation.

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100 Undercutting The penetration of a coating and the spread of delamination or corrosion from a break or pinhole in the film or from unprotected edges. Vehicle The liquid portion of paint, in which the pigment is dispersed; it is composed of binder and thinner. Vinyl Coating Coating in which the major portion of binder is from the vinyl resin family. Vinyl resins include polyvinyl acetate, polyvinyl chloride, copolymers of these, the acrylic and methacrylate resins, the polystyrene resins, etc. White Metal Blast Blast cleaning to white metal. This standard is defined in SSPC-SP-5 as a cleaned surface that, when viewed without magnification, shall be free of all visible oil, grease, dirt, dust, mill scale, rust, paint, oxides, corrosion products, and other foreign matter. Wire-Arc Spraying A thermal spray process using an electric arc discharge between two consumable wire electrodes of surfacing material. A jet of compressed gas is used to atomize and propel the surfacing material to the substrate being coated.