Vocabulary Flashcards
Anode
The electrode of a cell at which oxidation occurs. Electrons flow from the anode. Corrosion occurs at the anode.
Cathode
The electrode of a cell at which reduction occurs. Electrons flow toward the cathode.
Cathodic Protection
Technique used to reduce corrosion by making the surface the cathode.
Corrosion
The deterioration of a metal that results from a reaction with its environment.
Corrosion Cell
In order for corrosion to occur, a combination of an anode, cathode, return path, and electrolyte must be present.
Corrosion Inhibitor
A chemical substance that prevents or reduces corrosion.
Crevice Corrosion
Localized corrosion that occurs in an area that is within close proximity to the surface of another material.
Electrolyte
Chemical substance containing ions that migrate in an electric field.
Galvanic Series
Metals arranged according to their corrosion potentials in a given environment.
Generalized Corrosion
Corrosion that is distributed uniformly.
Localized Corrosion
Occurs at discrete sites on the surface.
Mill Scale
The oxide layer formed during fabrication of steel.
Passivation
Reduction of anodic reaction rate in corrosion.
Pitting Corrosion
Localized corrosion confined to small area
Return Path
Metallic pathway connects the anode to the cathode allowing passage of electrons.
Coatings Specification
Formal document containing information on a project.
Instrument Calibration History Reports
Contains information on how frequently each instrument is to be calibrated.
Materials Inventory Reports
Contain information on inventory of jobsite materials.
Safety Data Sheets
Form containing data of known substances in a particular product.
Quality Assurance
Systematic process that checks if the product or service is meeting specified requirements.
Quality Control
Procedure to ensure product or service meets the requirements of the customer.
Quality Control Technician
Inspector’s role. Responsible for observing and reporting technical aspects of a coating project and its conformance or deviation from the specification.
Standards
Term for codes that provide interchangeability and compatibility. Enhances quality, safety, economy.
Dew Point
Temperature at which moisture will begin to form on a steel surface.
infrared thermometers
Devices that measure temperature using radiation emitted from objects.
Magnetic Surface Contact Thermometer
Most common instrument to determine substrate temperature.
Psychrometric Chart
Graph of the physical properties of moist air at a constant pressure.
Psychometric Tables
Booklet to determine the relative humidity and dew point temperature.
relative humidity
The ratio of water vapor pressure in a given volume of air and temperature to the amount required to saturate the air at that temperature.
repeatability
same readings under ambient and target conditions in instrument.
sling psychrometer
Measures ambient air temperature to calculate dew point and relative humidity.
wind speed monitor
instrument for deciding if conditions are appropriate for coating.
additives
components of a coating added in small amounts to perform a specific function.
adhesion
process when dissimilar molecules cling together due to attractive forces.
barrier coatings
coating that has a high resistance to liquids and gases, and is applied over a base coating.
binder
nonvolatile portion of coating
inhibitive pigment
pigment that passivates the metal surface by forming a film or by plugging defects.
inorganic coatings
binders are made from non-living things, zinc or silicone.
organic coatings
binders made from once living things.
pigment
particles that impart color, corrosion control, or decorative properties.
sacrificial coatings
coatings that use an anodic metal to steel and corrodes preferentially.
solvents
liquefies the binder to allow for application.
acrylic
resin polymerized from acrylic acid, methacrylic acid, acrylonitrile, or esters.
alkyd
resin formed by reaction of polyhydric alcohols and polybaseic acids, partially derived from oils or fats.
convertible coating
cures by polymerization mechanisms even when solvent is involved.
chlorinated rubber
earliest coating. Eliminated for high VOCs.
curing
chemical process of developing the coating over a period of time.
epoxy
resin formed by reaction of aliphatic or aromatic polyols with epichlorohydrin . Presence of reactive oxirane end groups.
furan
resin formed by polymerization of furfuryl, furfuryl alcohol, or compounds containing furan ring.
latex emulsions
coatings containing a number of different resin particles that are covered with an emulsifier to keep them apart in liquid stage.
nonconvertible coatings
cure by evaporation of solvent. No chemical change to resins from liquid to solid state.
phenol
organic chemical widely used also known as carbolic acid.
thermosetting
coating formed by chemical cross linking reaction (oxidation polymerization, heat)
thermoplastic
material capable of being repeatedly softened by heat and hardened by cooling.
acidic cleaners
removes soil by chemical attack. Dissolve reaction products.
alkaline cleaners
saponifies most oils and greases, washes away contaminants.
ceramic grit
expensive abrasive with sharp cutting edges. effective on hard based materials.
crushed slag
cheap abrasive formed by metallurgical process. copper, nickel, coal, aluminum.
detergents
cleaners that function by solubilizing contaminants which can be washed away with water.
dry grit blasting
air blasting that uses concentrated stream of grit projected at surface to remove rust and creates a rough surface.
emulsion cleaners
cleaners sprayed onto surface and solubilize the contaminants.
faying surfaces
surfaces joined to create a friction grip.
gouges
sharp indentations on the substrate
inclusions
non-metallic phase, such as an oxide, sulfide, or silicate particle in a metal.
organic solvents
kerosine, turpentine, naphta, mineral spirits, toloul, xylol that clean the metal by dissolving grease contamination.
pre-cleaning
removing all visible contaminants from the surface.
surface lamination
most common surface defect. caused by rolling the steel.
surface profile
anchor pattern. irregular peaks and valleys profile on bare surface from abrasive blast or power tool cleaning.
venturi nozzle
450 MPH with an equal impact over the surface. Most effective for tough cleaning jobs.
water blasting
use of water with abrasive included in stream.
waterjetting
jetting water discharged from nozzle at pressures of 70 MPa or greater to prepare surface for coating.
weld splatter
particles of molten metal produced during welding and thrown onto the surface adjacent to the weld.
chlorides
salts of hydrochloric acid. chloride forms when the element chlorine picks up one elctron to form anion Cl.
nitrates
salts of nitric acid with an ion composed of one nitrogen and three oxygen atoms.
soluble salts
non-visible and require testing to determine presence. not soluble at all.
sulfates
salts of sulfuric acid.
BMR
Base metal readings. To adjust type 1 gause for surface roughness, measure blast profile of steel to be painted at a number of spots to obtain representative average value.
DFT Gauge Type 1
Instruments are magnetic pull-off gauges. Force required to pull a magnet from surface determines film thickness.
DFT Gauge Type 2
Electronic gauges to determine coating thickness.
Wet film comb
measures film thickness. Comb is pushed into film. Thickness measure shown on gauge.
High Voltage AC Holiday Detector
110V or 220V power supply. No ground wire. probe emits blue corona, attracted to any ground. Tesla coil.
High Voltage Constant Current DC Holiday Detector
Holiday detection in dielectric coatings. Pass electrode over the surface. Detector emits audible sound.
High Voltage Pulse Type DC Holiday Detector
ideal for moist conditions. Pass electrode over surface. Spark arcs through air gap and emits audible sound.
Low Voltage Holiday Detector
Wet sponge, sensitive low voltage. Powered by battery with output of 5-120 V DC.
