IMMERSION SERVICE - Use of a coating under water or other liquid; in this service, the coating frequently is called a lining.
IMPACT RESISTANCE - Ability of a coating to resist a sudden blow; ability to resist deformation from impact.
IMPINGEMENT CORROSION - A form of erosion-corrosion generally associated with the local impingement of a high-velocity, flowing fluid against a solid surface.
IMPRESSED CURRENT - An electric current supplied by a device employing a power source that is external to the electrode system. (An example is direct current for cathodic protection.)
IMPRESSED CURRENT ANODE - An electrode, suitable for use as an anode when connected to a source of impressed current, which is generally composed of a substantially inert material that conducts by oxidation of the electrolyte and, for this reason, is not corroded appreciably.
IMPULSE DIELECTRIC TEST - A method of applying voltage to an insulated wire through the use of electric pulses (usually 170 to 250 pulses per second) to determine the integrity of the wire’s insulation.
INBOARD - Inside the ship
INCIDENTAL FOOD CONTACT SURFACE - Any surface which is in such close proximity to food process areas as to at times be contacted by the food.
INCLUSION - A nonmetallic phase such as an oxide, sulfide, or silicate particle in a metal.
INCOMPATABILITY - Unsuitable for use together because of undesirable chemical or physical effects.
INDUCTION TIME - Sometimes called sweat-in time, the time interval that must elapse after mixing the components of multicomponent paint before application can begin.
INDUSTRIAL ENVIRONMENT - Atmospheric exposures that include urban communities, manufacturing centers, and industrial plants (but would not include heavy industrial environments such as coke plants, which fall under chemical environments). The atmosphere contains a considerable amount of gas containing sulfur and industrial fumes that increase the rate of corrosion and adversely affect the paint life.
INDUSTRIAL MAINTENANCE PAINTS - High performance coatings formulated for resistance to heavy abrasion, water immersion, chemicals, corrosion, temperature, electrical current or solvents.
INERT - A material which, under normal temperatures and pressures, does not react with other materials.
INERT PIGMENT - A nonreactive pigment, filler or extender.
INHIBITIVE PIGMENT - A pigment that when formulated into a coating provides active corrosion inhibition to a metal substrate or inhibits some other undesirable effect.
INHIBITIVE PRIMER - Primer containing inhibitive pigment or other material.
INHIBITOR - (1) General term for compounds or materials that slow down or stop an undesired chemical reaction, such as oxidation, corrosion, drying, skinning, mildew growth, etc. (2) In wet cleaning methods for steel, a material that can be added to the water or applied as a rinse to prevent flash rusting.
INORGANIC - Matter other than animal or vegetable. For example, minerals and salt.
INORGANIC ZINC - Another common coating used in marine cargo tanks. Used to carry non-aggressive cargos or organic solvents. It is inexpensive to apply, generally one coat. The drawbacks for Inorganic Zinc are that they are considered sacrificial coatings, they have limited resistance to acid or alkali, they oxidize over time so they are harder to remove and they will absorb cargo. They are not the right choice for a chemical tanker as they offer the owner limited cargo flexibility and sometimes pose great challenges for tank cleaning process as only a neutral Ph cleaning chemical can be used for cleaning tanks coated with zinc coating when changing from one cargo to another.
INORGANIC ZINC-RICH COATING - Coating containing a metallic zinc pigment (typically 75 wt% zinc or more in the dry film) in an inorganic vehicle.
INSOLUBLE - The inability to be dissolved.
INSTANT-OFF POTENTIAL - The polarized half-cell potential of an electrode taken immediately after the cathodic protection current is stopped, which closely approximates the potential without IR drop (i.e., the polarized potential) when the current was on.
INTERCOAT - A layer of paint that is “sandwiched” between two others. Also refers to something occurring between coats, as in “intercoat adhesion”.
INTERCOAT ADHESION - The ability of one coat of paint to adhere to the next.
INTERCRYSTALLINE CORROSION - See Intergranular Corrosion. - (1) detaching from the surface (adhesion) or (2) fracturing within a layer of coating or substrate (cohesion). The method can also be used to determine whether a coating will remain intact at a particular applied tensile force. This standard test method is defined in ASTM D 4541.
INTERDENDRITIC CORROSION - Corrosive attack of cast metals that progresses preferentially along paths between dendrites.
INTERFERENCE BOND - An intentional metallic connection, between metallic systems in contact with a common electrolyte, designed to control electrical current interchange between the systems.
INTERFERENCE CURRENT - See Stray Current.
INTERGRANULAR CORROSION - Preferential corrosion at or along the grain boundaries of a metal (also known as intercrystalline corrosion).
INTERGRANULAR STRESS CORROSION CRACKING - Stress corrosion cracking in which the cracking occurs along grain boundaries.
INTERNAL OXIDATION - The formation of isolated particles of oxidation products beneath the metal surface.
INTUMESCENCE - The swelling or bubbling of a coating usually caused by heating. [The term is commonly used in aerospace and fire-protection applications.]
ION - An atom or group of atoms possessing a positive or negative electric charge as a result of having lost or gained an electron.
IR DROP - The voltage across a resistance in accordance with Ohm’s Law.
IRON OXIDE - An oxide of iron. The natural occurring state of steel.
IRON ROT - Deterioration of wood in contact with iron-based alloys.
ISOCYANATE - A compound containing one or more of the chemical group -N=C=O. Isocyanates comprise one major component of two-component polyurethane coatings. When the isocyanate groups are crosslinked with a hydroxyl-containing material (polyol), a polyurethane polymer is formed.
ISOPROPYL ALCOHOL (IPA) - A volatile, flammable liquid used as a solvent commonly known as rubbing alcohol.