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Glossary of Pretreatment and Stripping Terms

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					                                   Glossary of




                                                                                                                                         Copyright, CSC Publishing, Powder Coating
                        Pretreatment and Stripping Terms
                   A                         Alkaline descaling. A chemical process       Ash. The nonvolatile inorganic matter
                                             for removing scale. A typical descaling      of a compound, which remains after sub-
Abrasive. Agent used for abrasive blast
                                             solution uses caustic soda with additives,   jecting it to high temperatures.
cleaning. Examples include sand, grit,
                                             such as detergents and chelating agents.
steel shot, and glass or plastic beads.
                                                                                                              B
Acid. A species which reacts in liquid       Alkalinity. A measurement of the quan-
                                                                                          BTU. British thermal unit. The amount
water to generate hydrogen ions (repre-      tity of chemicals present in the water
                                                                                          of heat needed to raise the temperature of
sented as cations—H+ or hydronium            that can neutralize acids. These include
                                                                                          one pound of water 1°F.
                                     -
H3O+; anions such as sulfate, SO42 ; and     carbon dioxide, bicarbonate, carbonate,
nitrate, NO3-) which were associated         and hydroxides. See titratable alkalinity.
                                                                                          Base. A species which when dissolved in
with the H+ in the acid are also released.                                                                              -
                                                                                          water generates hydroxide (OH ) ions or
                                             Alum. See aluminum sulfate.
                                                                                          is capable of reacting with an acid to
Acid descaling. A process using acid to                                                   form a salt.
dissolve oxide and scale. See pickling.      Aluminum sulfate. An aluminum salt
                                             commonly used as a flocculant by munici-
                                                                                          Baume Scale. Specific gravity scale
Acidity. Measure of the free acid present.   pal water treatment plants.
                                                                                          used for taking the relative weight of a
                                                                                          liquid as compared to the weight of an
Activation. Process of removing last         Ambient temperature. Room tempera-
                                                                                          equal volume of a standard liquid. The
trace of oxide on a metal surface and a      ture or temperature of surrounding area.
                                                                                          lighter-than-water, or oil scale, has as its
thin layer of the metal itself to ensure
                                             Amphoteric. A substance, such as alu-        zero point, the distance to which a
that the metal surface is electrochemi-
                                             minum, capable of acting either as an        hydrometer sinks in a mixture of one
cally active. See etching.
                                             acid or a base.                              part salt in nine parts of water. The 10°
                                                                                          point is determined in pure water. The
Active metal. Metal in the condition of
                                             Amphoteric surfactant. Surfactant            distance between these two points is
high chemical activity that is more sus-
                                             having both negatively and positively        divided into ten equal parts and these
ceptible to corrosion.
                                             charged functional groups.                   spaces are added above the 10°-mark as
Adsorption. The binding of a molecule                                                     high as needed for the liquid where the
to a surface (solid or liquid) by nonspe-    Anion. A negatively charged ion. See ion.    hydrometer is most frequently used. The
cific physical forces. For example, the                                                   heavier-than-water, or acid, scale uses
removal of free chlorine and chloramines     Anionic surfactants. Surfactants that        pure water for its zero point. The point to
by activated carbon is through the mech-     give negatively charged ions in an aque-     which the hydrometer sinks in a mixture
anism of adsorption.                         ous solution.                                of 15 parts salt to 85 parts of water is
                                                                                          marked 15°. Between these two points,
Age tank. A tank used to store a known       Anchor pattern. Surface profile, usu-        the space is divided into 15 equal parts.
concentration of chemical solution for       ally after blasting.                         These spaces are added below the 15°-
feed to a chemical feeder. Also called a                                                  mark to make a total of 0° to 70°. French
day tank.                                    Anhydrous. Dry. Free of water in any         scientist, Antoine Baumé, designed this
                                             form.                                        type of hydrometer.
Air jet. Type of sandblasting gun in
which the abrasive is conveyed to the        Antifoaming agent. Material added to         Best available technology (BAT). A
gun by partial vacuum.                       pretreatment chemical solutions to reduce    level of technology represented by a higher
                                             the tendency of materials to foam.           level of wastewater treatment technology
Air knife. Mechanical device that uses a                                                  than needed by best practicable technol-
small amount of compressed air to pull in    Aquablast. A surface cleaning process        ogy (BPT). BAT is based on the very best
large volumes of surrounding air and pro-    where an abrasive material is suspended      (state of the art) control and treatment
duce a high-flow, high-velocity curtain or   in water. The resulting slurry is pressur-   measures that have been developed, or are
sheet of air.                                ized and ejected through a nozzle. This      capable of being developed, and that are
                                             process can use higher pressures than        economically achievable within the appro-
Alkali. Caustic. Inorganic substances        other types of blasting and quickly re-      priate industrial category.
that share the characteristic of being       moves surface metal and leaves a good
strongly basic (high pH). Examples           surface finish.                              Best practicable technology (BPT). A
include sodium hydroxide, caustic soda,                                                   level of technology represented by the
and lye.                                     Aqueous. A water-based material.             average of the best existing wastewater
treatment performance levels within the      Chlorine. Chemical used to disinfect           Copper sulfate test. Test to determine
industrial category.                         municipal water.                               the presence of mill scale or passivated
                                                                                            metal. A copper color indicates absence of
Biodegradable surfactant. Surfactant         Cleaner. Detergent, alkali, acid, solvent,     mill scale and presence of bare steel when




                                                                                                                                          Copyright, CSC Publishing, Powder Coating
that may be decomposed by biological         or other cleaning material, often water- or    steel is swabbed with a 5- to 10-percent
action.                                      steamborne, used to clean and degrease         solution of acidified copper sulfate.
                                             parts before powder application.
Blast cleaning. Removal of surface                                                          Corrosion. Decomposition or reaction of
contaminate from a part by using an          Coagulant. A chemical which causes             a metal with oxygen, water, or other
air- or mechanically propelled abrasive.     dispersed colloidal particles to become        chemicals, when exposed to a particular
                                             destabilized, thereby, aiding in their         environment.
Blemish. Any surface imperfection of a       removal during municipal water treat-
coating or substrate.                        ment. Aluminum and iron salts are com-         Counterflow. Transporting overflowed
                                             monly used for this purpose.                   solution from one washer stage to
Blow-off. Removal of particulate and                                                        another for reuse.
fibers from materials in preparation for     Coagulation. A chemical (coagulant),
                                                                                            Creepage. Corrosion under a scribe line
powder application using compressed or       most commonly alum, is added to water
                                                                                            or edge after salt spray or other testing.
high-volume, fan-driven air.                 to destabilize colloidal particles by neu-
                                                                                            See scribe creep.
                                             tralizing their electrical charges. Coagu-
Bright blast. White metal surface blast.     lation is used together with flocculation
See NACE No. 1 white metal blast cleaned     as a process for colloidal removal.
                                                                                                                D
surface finish.                                                                             Day tank. See age tank.
                                             Colloid. Undissolved, submicron-sized
Brush-off blast. Lowest blast cleaning       particles that are suspended and well dis-     Deflocculation. A cleaning procedure
standard. See NACE No. 4 brush-off blast                                                    that breaks down soil into very fine parti-
                                             persed in a solution and will not readily
cleaned surface finish.                                                                     cles, which are maintained in a dispersive
                                             settle out on standing.
                                                                                            phase to prevent agglomeration.
Buffer. A solution or liquid whose chemi-    Compaction. The undesirable physical
cal makeup neutralizes acids or bases                                                       Defoamer. See antifoaming agent.
                                             compression of a reverse osmosis or ultra-
without a great change in pH.                filtration membrane, resulting in reduced      Degreaser. Solvent or compounded
                                             flux rates. Higher temperatures and pres-      material for removing oils, fats, or grease
Builder. A chemical that aids in soil        sures accelerate this phenomenon.              from a substrate. Also the apparatus in
removal without significant influence on
                                                                                            which the operation is carried out.
surface tension.                             Conductivity. Conductivity is a quanti-
                                             tative measure that describes the ability      Degreasing. Removal of grease, oil, and
                   C                         of an aqueous solution to carry electric       other fatty matter by the use of solvents
 CFS. Cubic feet per second. A measure       current and depends on the presence of         or chemical cleaners, electro, or heat
of flow rate.                                ions in the solution. Solutions of inorganic   processes.
                                             ions are relatively good conductors—and
Cation. A positively charged ion. See ion.   exhibit high conductivity—whereas solu-        Deionization. The removal of ions from
                                             tions of organic molecules are rather poor     a solution by ion exchange.
Cationic surfactant. Positively              conductors—and exhibit low conductivity.
charged surfactant molecule.                 Highly purified water is also a poor con-      Deionized water (DI water). Water con-
                                             ductor. Conductivity is expressed in units     taining no ions other than hydrogen and
Caustic. A strong chemical base.                                                            hydroxyl ions. Typically produced through
                                             of Siemens/centimeter (mhos/cm). Con-
                                             ductivity measurements can be used to          using ion exchange resins and used for
Cellulose acetate. A synthetic polymer                                                      parts after a seal rinse in a spray washer.
                                             monitor the performance of reverse osmo-
derived from naturally occurring cellu-
                                             sis equipment. The measurement is tem-
lose and widely used in fabricating                                                         Descaling. Removal of mill scale or caked
                                             perature dependent and should be mea-
membranes. The polymers used for                                                            rust from steel by chemical and-or
                                             sured with a temperature-compensated
water purification membranes may be                                                         mechanical means, sometimes assisted by
                                             meter. The usual reference temperature
diacetate, triacetate, or blends of these                                                   flame cleaning.
                                             is 77°F (25°C). Conductivity measure-
materials.
                                             ments can also be used to estimate total       Detergent. An alkaline or ionized clean-
Chelant. Chemical that complexes             dissolved solids in water. See resistivity.    ing or emulsifying agent. A formulation
metal ions in soluble form.                                                                 that will remove soil. See surfactant.
                                             Contaminants. Foreign material, such
Chromate rinse. See Chromic acid rinse.      as dirt, which can be detected in the          Dilute. To make thinner or less concen-
                                             cured powder coating.                          trated by adding liquids such as water
Chromic acid rinse. A chromic acid                                                          or solvent.
solution used after zinc or iron phosphate   Conversion coating. Inorganic pre-
to passivate the metal at the base of        treatment—zinc or iron phosphate—for           Dilution ratio. Ration by which a given
cracks or pinholes in the phosphate coat-    metal substrates that prepares the sur-        solvent or solution may be diluted with-
ing. Used to improve corrosion resistance.   face for powder coating.                       out adverse effects.
Dispersion. Suspension of one sub-              Enzyme. For detergency, an amino acid          Flux rate. The rate per unit of area at
stance in another.                              polyester derived from bacteria, that          which water passes through a semiper-
                                                breaks down proteins (protease), fats          meable membrane, such as those used
Drag-in. The water or solution that ad-         (lipase), or starches (amylase).               for ultra filtration or reverse osmosis.




                                                                                                                                                Copyright, CSC Publishing, Powder Coating
heres to workpieces introduced into a bath.
                                                Erosion. Wearing away of a coating to          Fouling. The deposition of insoluble mate-
Drag-out. Process of solution en-               expose the undercoat and substrate.            rials, such as bacteria, colloids, oxides, and
trapment being pulled with the product,                                                        waterborne debris, onto the surface of a
typically out of the washer zone or coat-       Etch. Wear away or roughen a surface           reverse osmosis or ultra filtration mem-
ing enclosure.                                  with, or as if with, an acid.                  brane. Fouling is associated with decreased
                                                                                               flux rates and may also reduce the rejection
                                                Etching. Surface preparation of metal          rates of reverse osmosis membranes.
Drain. A piping system used to collect
                                                by chemical process; removal of a layer
and carry off surface and ground water.
                                                of the base metal.
                                                                                                                    G
Dry blasting. Any form of blasting
                                                Evaporation. The physical process by           GPD. Gallons per day.
where the abrasive agent is not carried
                                                which a liquid substance is converted to
in water.                                                                                      GPM. Gallons per minute.
                                                a gas or vapor.

                                                                                               GPY. Gallons per year.
                     E                                              F
Effluent. Any spent liquors or other waste      Face rusting. Appearance of rust on an         Gallon. Unit of volumetric measure (4
material which are emitted by a source,         apparently unblemished coated surface.         quarts, or 3.785 liters).
such as waste from plating shops, pickling
                                                Feed water. Water entering a purifica-         Galvanized steel. Steel coated with a
tanks, and sewage treatment plants.
                                                tion system or an individual piece of pur-     layer of metallic zinc.
                                                ification equipment, such as an ultrafil-
Effluent limitations. Any restrictions,
                                                ter or reverse-osmosis system.                 Gray blast cleaning. A commercial blast
established by the government or by
                                                                                               standard. See NACE No. 3 commercial
management, on quantities, rates, and           Filiform corrosion. Corrosion resem-           blast cleaned surface finish.
concentrations of chemical, physical, bio-      bling a thread-like formation; usually
logical, and other constituents that are        caused by poor substrate cleaning or rins-     Grit. Abrasive obtained from slag and
discharged from paint sources.                  ing.                                           various other materials.

Emulsion. Suspension of colloidal-sized,        Filter. A porous material on which solid       Grit blasting. Abrasive cleaning of a
immiscible liquid droplets in another liq-      particles present in the air or in other       surface by blasting with angular chilled
uid; two phases present.                        fluids which flows through it are largely      iron grit, aluminum oxide, or any crushed
                                                caught and retained.                           or irregular abrasive.
Emulsion cleaning. A cleaning tech-
nique that emulsifies contaminants.             Filtration. The process of segregation of
Emulsions are mixtures of two liquids;
                                                                                                                    H
                                                phases, such as the separation of sus-
one holds the other in a suspension. The                                                       Hexavalent chrome. Chromium most often
                                                pended solids from a liquid or gas, usually
liquids will typically have different polari-                                                  used as a seal rinse in a five-or-more-stage
                                                by forcing a carrier gas or liquid through a
ties and will dissolve different types of                                                      pretreatment system. Has a +6 valence
                                                porous medium.
materials. One of the liquids is usually                                                       Hex and is considered a reactive seal rinse.
water and the other will have nonpolar          Flame cleaning. Surface preparation of
                                                                                               Hydroblasting. Cleaning with high-
properties and they can dissolve nonpolar       steel using flame to burn off contaminates.
                                                                                               pressure water jet.
contaminants, such as oil and grease,
from metal surfaces.                            Flash rusting. Very thin coating of rust
                                                or oxide occurring within minutes to           Hydrogen ion concentration. pH. See pH.

End point. Samples are titrated to the          hours after applying a pretreatment solu-
end point. This means that a chemical is        tion.                                                                I
added drop by drop to a sample until a cer-                                                    Immiscible. Descriptive of the two or
                                                Flocculant. A substance used in combi-         more fluids that aren’t mutually soluble.
tain color change (blue to clear, for exam-
                                                nation with coagulants, which causes sub-
ple) occurs. This is called the end point of
                                                microscopic, suspended matter (colloids) to    Impeller. Located within the pump housing,
the titration. In addition to a color change,
                                                aggregate into larger particles that can be    this device provides the mechanical action
an end point may be reached by the for-
                                                removed by settling or filtration.             needed to pump the washer solution through
mation of a precipitate or the reaching of a
                                                                                               the piping in a spray treatment system.
specified pH. An end point may be de-           Flowmeter. An instrument for measur-
tected by the use of an electronic device       ing the rate of flow of a fluid moving         Impingement. A process resulting in a
such as a pH meter. The completion of a         through a tube, pipe, or duct system. The      continuing succession of impacts between
desired chemical reaction.                      instrument is calibrated to furnish vol-       liquid or solid particles and a solid surface.
                                                ume or mass rate of flow.
Indicator (pH) paper. A vegetable-            NACE No. 1 white metal blast cleaned               Neutralization. Addition of an acid or al-
dyed paper that indicates relative acidity    surface finish. This finish is a surface           kali (base) to a liquid to cause the pH of the
or basicity (alkalinity).                     with a gray-white uniform metallic color,          liquid to move toward a neutral pH of 7.0.
                                              slightly roughened to form a suitable




                                                                                                                                                  Copyright, CSC Publishing, Powder Coating
Industrial waste water. Water dis-            anchor pattern for coatings; this surface                               P
charged from an industrial process as a       shall be free of all oil, grease, dirt, visible
                                                                                                 pH paper. See indicator paper.
result of formation or use in that process.   mill scale, rust corrosion products, oxides,
                                              paint, or any other foreign matter; the sur-       pH value. Measure of acidity or alkalin-
Industrial water. Water (including its
                                              face shall have color characteristic of the        ity. pH7 is neutral. The pH values of acids
impurities) used directly or directly in
                                              abrasive media used; photographic or               are less than 7. The pH values of alkali
industrial process.
                                              other visual standards of surface prepara-         bases are greater than 7.
                                              tion may be used to further define the sur-
Inorganic. Designation of compounds
                                              face. Syn: white blast.                            PPM. Parts per million.
that generally don’t contain carbon.
                                              NACE No. 2 near-white metal blast                  Paint and varnish remover. Liquid,
Interfacial tension. See surface tension.
                                              cleaned surface finish. This finish is             principally solvents, sometimes with wax
                                              one from which all oil, grease, dirt, visible      or thickeners, which is applied to a coated
Ion. An atom or group of atoms that has
                                              mill scale, rust corrosion products, oxides,       surface in order to soften the old coating
acquired a net of electric charge by gain-
                                              paint, or other foreign matter have been           and bring it to such a condition that it can
ing or losing one or more electrons.
                                              removed from the surface except for very           be easily removed. Syn: stripper.
                                              light shadows, very slight streaks, or
Iron phosphate coating. Conversion
                                              slight discolorations; at least 95 percent of      Parkerized. Descriptive of iron or steel,
coating. Chemical deposition on steel and
                                              the surface shall have the appearance of a         which has received a rust-resisting treat-
aluminum for corrosion protection.
                                              surface blast cleaned to a white metal sur-        ment by being dipped in a boiling solution
                                              face finish and the remainder shall be lim-        of manganese dihydrogen phosphate; this
                    L                         ited to the light discoloration mentioned          protective coating also improves the bond-
Laminar scale. Rust formation in heavy        above; photographic or other visual stan-          ing (adhesion) of paint and lacquers.
layers.                                       dards of surface preparation may be used
                                              to further define the surface.                     Passivation. Conversion of metal surface
                   M                                                                             to less reactive state to reduce corrosion
                                              NACE No. 3 commercial blast cleaned
Media. Aggregate used to effect dispersion                                                       rate of metal surface.
                                              surface finish. This finish is defined as
in certain types of production equipment,     one from which all oil, grease, dirt, rust
such as ball pebble and sand mills.                                                              Phosphate. Chemical radical (PO4)-3. In
                                              scale, and foreign material have been com-         coating operations, zinc, iron, or man-
                                              pletely removed from the surface and all
Media mill. Any mill using any one of                                                            ganese phosphate is used as a conversion
                                              rust, mill scale, and old paint have been
the various types of grinding media such                                                         coating to prepare the part for coating
                                              completely removed except for slight shad-
as sand, steel, ball, and pebble.                                                                application.
                                              ows, streaks, or discolorations; if the surface
                                              is pitted, slight residues of rust or paint        Phosphating. Pretreatment of steel or
Mild steel. Structural steel or plate, mal-
                                              may be found in the bottom of the pits; at         certain other metal surfaces by chemical
leable iron-based alloy. SAE 1020, with a
                                              least two thirds of the surface area shall be      solutions containing metal phosphates and
carbon content of up to 2.5 percent.
                                              free of all visible residues and the remain-       phosphoric acid as the main ingredients, to
                                              der shall be limited to light discoloration,       form a thin layer which serves as a good
Mill scale. Oxide layer formed on steel
                                              slight staining, or light residues mentioned       base for subsequent paint coats.
by hot rolling process.
                                              previously; photographic or other visual
                                              standards of surface preparation may be            Phosphatize. Formation of thin, inert
Miscible. Capable of mixing or blending
                                              used to further define the surface.                phosphate coating on surface, usually by
uniformly.
                                                                                                 treatment with phosphoric acid or other
Molten salt. Inorganic chemical or chem-      NACE No. 4 brush-off blast cleaned sur-            phosphate compound.
icals that are used at temperatures above     face finish. This finish is one from which
                                              oil, grease, dirt, rust scale, loose mill scale,   Pickling. Use of chemical solution to
their melting point for heat transfer, heat
                                              loose rust, and loose paint or coatings are        prepare surface for coatings or bonding
treating, or metal cleaning purposes.
                                              removed completely, but light mill scale           by dissolving away surface oxides and
Molten salt bath. A specially designed        and tightly adhered rust, paint, and coat-         other impurities.
vessel used to contain and heat molten        ings are permitted to remain provided they
                                                                                                 Power wash. Multistage cleaning and
salt processes.                               have been exposed to the abrasive blast
                                                                                                 conditioning machine or structure to
                                              pattern sufficiently to expose numerous
                                                                                                 transport material using some form of
                                              flecks of the underlying metal fairly uni-
                   N                          formly distributed over the entire surface;
                                                                                                 conveyor system.
NACE. National Association of Corrosion       photographic or other visual standards of          Pretreatment. Chemical cleaning and
Engineers.                                    surface preparation may be used to further         etching before powder application in
                                              define the surface.                                order to improve adhesion and corrosion
                                                                                                 resistance.
Product water. The purified water              Sandblast. Blast cleaning using sand           Solution. Mixture formed when one
stream from purification equipment, such       as an abrasive.                                material (solid or liquid) is dissolved into
as reverse osmosis units and ultrafilters.                                                    a liquid.
                                               Sanitary shield or shroud. Shield that




                                                                                                                                             Copyright, CSC Publishing, Powder Coating
Profile. Surface contour; usually used as      protects the conveyor from excessive           Solvent. Liquid or blend of liquids used
a blasting term.                               moisture in the washer.                        to dissolve or disperse a paint. A true sol-
                                                                                              vent is a single liquid that can dissolve
Pyrolysis. Decomposition or transforma-
                                               Saponification. Decomposition of               paint.
tion of compound caused by heating.
                                               esters to their constituent alcohols and
                    R                          fatty acids, usually accomplished with         Solvent washing. Cleaning with solvent.
Reagent. A substance used in chemical          an alkali.
                                                                                              Spray chamber. An enclosure that sur-
reaction to detect, measure, examine, or
                                               Scale. Rust occurring in thin layers,          rounds the pretreatment process and
produce other substances.
                                               commonly found on hot-rolled steel.            contains overspray.

Recovered solvent. Solvent which is ex-                                                       Steam clean. Cleaning with live steam.
                                               Scaler. A hand-cleaning chisel used to
tracted from a process or exhaust stream
                                               remove scale.
usually by absorption or condensation.                                                        Stripper. Device or chemical used to
                                               Scaling. In reference to reverse osmosis       remove a coating from a substrate by
Reverse osmosis (RO). Method of re-
                                               equipment, scaling is the precipitation of     means of pyrolysis, chemical attack-dis-
moving ions from water to make purer
                                               sparingly soluble salts, such as calcium       solution, mechanical abrasion, or a com-
water. Method of removing metal ions
                                               carbonate, onto the surface of a mem-          bination, such as high heat burn-off,
from an aqueous solution via semiper-
                                               brane. Scaling is associated with de-          molten salt, grit blast, and alkaline strip-
meable membranes.
                                               creased flux and reduced reverse osmo-         pers.
Rust. Corroded iron. Red iron oxide de-        sis rejection rates.
                                                                                              Suction feed. Siphons abrasive to the
posited on metal. Also other metal oxides
                                               Scribe creep. Measurement taken from           nozzle of a sandblaster.
formed by corrosion.
                                               the scribe line in a salt-spray test to mea-
                                               sure the quality or corrosion resistance       Surface active agent. See surfactant.
Rust bloom. Discoloration indicating
the beginning of rusting.                      of a coating system.
                                                                                              Surface preparation. Operations nec-
Rust grade scale. In evaluating the re-        Seal rinse. A final rinse in a spray           essary to prepare the surface to receive a
sistance to rusting, the linear, numerical     washer that passivates the pretreated          coating.
rust grade scale is an exponential function    surface to prevent oxidation and provide
                                               corrosion resistance in the field.             Surface tension. Cohesive surface on a
of the area of rust so that slight amounts
                                                                                              liquid surface. Force attracting molecules
of first rusting have the greatest effect on
                                               Sedimentation. The process by which            at the surface to the bulk of the material
lowering the rust grade (ASTM D-610).
                                               solids are separated from water by grav-       or energy difference between two phases
Rust resistance. The ability of a coating      ity and deposited on the bottom of a con-      (interfacial tension).
to protect the substrate of iron or its        tainer or basin.
alloys from rusting.                                                                          Surfactant. Chemical used to adjust sur-
                                               Semipermeable. Descriptive of a mate-          face tension of a material. Term con-
Rust-inhibitive washes. See conversion         rial, such as a reverse osmosis or ultrafil-   tracted from surface active agent.
coating.                                       tration membrane, which allows the pas-
                                                                                              Suspension. Mixture of fine particles of
                                               sage of some molecules and prevents the
Rusting. Corrosion on the surface of iron                                                     any solid with liquid or gas.
                                               passage of others.
or ferrous metals resulting in the forma-
tion of products consisting largely of         Shot blasting. Blast cleaning using            Sweep blast. See NACE No. 4 brush-off
hydrous ferric oxide.                                                                         blast cleaned surface finish.
                                               steel shot as the abrasive.

Rustproofing. Processes applied to                                                                                T
                                               Shot peening. See shot blasting.
steel, including coating or galvanizing,
                                                                                              Titratable Alkalinity. When certain
but most often refers to phosphating and       Soap. Salt of fatty acid; used to desig-       anions, such as carbonate (CO3-), are dis-
similar low-duty rust preventatives.           nate all detergents.                           solved in water, they bind hydrogen ions
                                                                                              (H+) and thus shift the water equilibrium
                    S                          Soils. Foreign matter on a part’s sub-         to produce free hydroxyl ions (OH-). This
                                               strate before being cleaned in a pre-          excess concentration of OH- is termed
Salt-spray test. Corrosion test using
                                               treatment system. Can be organic or            alkalinity. Titratable alkalinity can be
salt (NaCl) solution sprayed as a mist in
                                               inorganic.                                     measured by determining the amount of
a heated humidity chamber to simulate
seashore conditions, or to accelerate cor-                                                    H+ (in mEq or mmol) which must be
                                               Solubilizer. Chemical used to hold mate-
rosion at a controlled rate. (ASTM Test                                                       added to water to restore the pH to 7.0,
                                               rials in suspension in a solution.
B-117).                                                                                       the condition of neutrality where [H+] =
                                                                                              [OH-].
Titrate. To titrate a sample, a chemical        Water hardness. Presence of heavy            S. LeSota, ed., Coatings Encyclopedic
solution of known strength is added drop        metals, commonly calcium (Ca) or mag-        Dictionary (Blue Bell, Pa.: Federation of
by drop until a certain color change, pre-      nesium (Mg), in solution.                    Societies for Coatings Technology, 1995).
cipitate, or pH change in the sample is




                                                                                                                                         Copyright, CSC Publishing, Powder Coating
observed (end point). Titration is the          Water softness. Absence of high concen-      The Powder Coating Institute, Powder
process of adding the chemical reagent in       tration of Ca or Mg. Water is considered     Coating Terms and Definitions (Alex-
increments until completion of the reac-        soft when concentration is below 100         andria, Va., 1996).
tion, as signaled by the end point.             parts per million (ppm) (as CaCo3).
                                                                                             L. Regenstein. Metal Finishing Industry
Total dissolved solids (TDS). A mea-            Water spotting. Visual blemish that          Pollution Prevention Notebook (Boston:
surement of the solids content of water in      occurs on the surface in areas where         Northeast Waste Management Official’s
the parts per million (ppm).                    water droplets have dried and left dis-      Association).
                                                solved solids. Whitish blemishes on a pre-
Tooth. Profile. Mechanical anchorage.           treated part where minerals in the water
Surface roughness.                              have left a deposit on the surface.


                    U                           Wetting. Ability of a liquid to spread
                                                over a surface.
Ultrafilter. A membrane based filtration
system in which the pore sizes range from       Wetting agent. See Surfactant.
0.001 to 0.1 micron.
                                                White blast. Blast cleaning to white
                    V                           metal surface. See NACE No. 1.
Vapor degreasing. The use of a con-
densing solvent vapor to dissolve and           White metal. Blasting metal to a speci-
rinse away oil and grease before assem-         fied appearance, such as SSPC-SP-10,
bly or coating.                                 and NACE No.1.


Vestibule. Small entrance hall to the pre-      White rust. White corrosion products (zinc
treatment washer.                               hydroxide and zinc oxide) on zinc-coated
                                                articles. Syn: white storage stain.

                    W
                                                                   Z
Washer crystal. Particles caused by crys-
tallization of minerals, additives, cleaners,   Zinc phosphate coating. Conversion
or chemicals found in the water of power        coating used on steel and galvanized
washers.                                        steel parts to improve coating adhesion
                                                and corrosion resistance.
Washer drain zone. The space in
between spray zone within the washer
tunnel.                                         Definitions come from the following
                                                sources:
Washer process zone. The spray treat-
ment zones within the washer tunnel.            California State University Sacramento
                                                Foundation, Office of Water Programs.
Washer vestibule. The portion of the            Master Glossary of Water and Wastewater
washer tunnel at the entrance and exit.         Terms (Sacramento, Calif., [www.owp.
                                                csus.edu/glossary/ glossary.htm]).
Washing. The combination of mechani-
cal and chemical means to remove soil.          GE Osmonics, Tech Note 120 (Kent,
                                                Wash., 2003).
Water blasting. Blast cleaning of metal
using high-velocity water.
                                                L. Cecil and J. Beckwith. The Glossary of
                                                Standard Finishing Technology (Dear-
Water break. The appearance of a discon-
                                                born, Mich.: Association of Finishing
tinuous film of water on a surface, signify-
                                                Processes of the Society of Manufactur-
ing nonuniform wetting and usually asso-
                                                ing Engineers, 1991).
ciated with a surface contamination.

                                                R. Lange, ed., Detergents and Cleaners:
Water-break-free. The ability of the
                                                A Handbook for Formulators (Cincinnati:
rinse water to cover the surface in an un-
                                                Hanser Gardner, 1994).
broken film.

				
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