Glossary of Terms

Anion Exchanger – An Ion exchanger with positively charged groups covalently attached to the support.  It can reversibly bind anions.

Anode – The electrode at which oxidation occurs.

Atomic Absorption Spectroscopy – A technique in which the absorption of light by free gaseous atoms in a flame or furnace is used to measure the concentration of atoms.

Barrel Plating – A large quantity of smaller work items that are placed in a self-driven, poly-pro and perforated cylinder shaped container that is submerged 75% in the tank in the horizontal position, so that numerous work items may be processed simultaneously without independent fixtures.

Cathode – The electrode at which reduction occurs.

Cation Exchanger – An ion exchanger with negatively charged groups covalently attached to the support.  It can reversibly bind cations.

Chelator – A ligand that binds to a metal through more than one atom.

Concentration – An expression of the quantity per unit volume or unit mass of a substance.  Common measurements are grams/liter (g/l) or ounces/gallon (oz/gal).

Cross Section – A term to describe a work item or sample that has been cut in order to view the coating and substrate on the same plane normally under high magnification.

Crystallization – Occurs when a substance comes out of solution slowly to form a solid with a regular arrangement of atoms.

Degrease – To remove all oil and soil (usually organic) from work items before all other process operations begin.

DeMag – Ferrous parts must be without any magnetic properties prior to plating to avoid small particle attraction to the part.

DI Rinse – A rinse tank that uses high quality, deionized water.

DI Water System – A water purification system made of at least three resin beds to absorb first, negative ions and then passed to the second bed for positive ions and finally a combination of both negative and positive resins (mixed bed). DI water quality is measured in “mega-ohms resistance” with the highest quality being 17 mega-ohms.

EDS – Engineering Data Sheet – A document completed by the customer that is required to answer necessary questions regarding alloy and function of the submitted work item.

Electrode – A device at which or through which electrons flow into or out of chemical species involved in a redox reaction.

Electrochemical – Use of electrical measurements on a chemical system for analytical purposes.  Also refers to use of electricity to drive a chemical reaction or use of a chemical reaction to produce electricity.

Electrolyte – A substance that produces ions when dissolved.

Electronic Balance – A balance that uses an electromagnetic servomotor to balance the load on a pan.  The mass of the load is proportional to the load needed to balance it.

End Point – The point in a titration at which there is a sudden change in a physical property, such as indicator color, ph, conductivity, or absorbance.  Used as a measure of the equivalence point.

Endothermic Reaction – Heat must be supplied to reactants for them to react.

Equilibrium – The state in which the forward and reverse rates of all reactions are equal, so that the concentrations of all species remain constant.

Equivalence Point – The point in a titration at which the quantity of titrant is exactly sufficient for stoichiometric reaction with the analyte.

Exothermic Reaction – Heat is liberated when products are formed.

Filtrate – The liquid is passed through a filter.

Fixture – To suspend the work item so that all surfaces are exposed to the solution. (examples – wire, racks)

Galvanic Cell – One that produces electricity by means of a spontaneous chemical reaction.

Graduated Cylinder – A tube with volume calibrations along its length.

Hydrolysis – “Reaction with water”.  The reaction B + H2O = BH+ + OH- is often called hydrolysis of a base.

Inclusion – An impurity that occupies lattice sites in a crystal.

Indicator – A compound having a physical property (usually color) that changes abruptly near the equivalence point of a chemical reaction.

Knoop Micro Hardness – A scale of hardness determined under high magnification.  Vickers and Bernel are other micro hardness scales.  Micro hardness is the only method to check the true hardness of small amounts of materials such as coatings.

Masking – To prevent the plating from depositing on the selected surface.

Meniscus – The curved surface of a liquid.

MTO – Metal Turn Over – When 100% of the available nickel is plated out onto either work items or dummy parts and then replaced.

Neutralization – The process in which a stoichiometric equivalent of acid )or base) is added to a base (or acid).

Occlusion – An impurity that becomes trapped (sometimes with solvent) in a pocket within a growing crystal.

pH – Defined as pH= - log AH+, where AH+ is the activity of H+.  In most approximate applications, the pH is taken as –log {H+].

pH meter – A very sensitive potentiometer used in conjunction with a glass electrode to measure pH.

Pipet – A glass tube calibrated to deliver a fixed or variable volume of liquid.

Plastic Deformation – During the machining and or grinding operation of a work item, some material is compressed into the work item rather than being removed by the cutting tool or grinding wheel.

Rectifier – A power supply that converts AC current to DC used to electro-clean and nickel strikes.

Reducing Agent – A substance that donates electrons in a chemical reaction.

Reduction – A gain of electrons or a lowering of the oxidation state.

Rockwell Hardness – A machine and scale used to check the hardness of bulk materials such as a bar of steel.

RSA – Required Surface Area – Usually referred to minimal surface area/load.

Sample Mount – An item, sample or work item molded into a plastic material for holding the item for further examination or processing (puck).

Spectrophotometer – A device used to measure absorption of light.  It includes a source of light, a wavelength selector (monochromator), and an electrical means of detecting light.

Standard Solution – A solution whose composition is known by virtue of the way it was made from a reagent of known purity.

Stress Relief – To return the substrate matter to a relaxed condition by heating the material causing thermal expansion and allowing it to slowly cool.

Surface Stress – A work item with compressed or _______ areas (plastic deformation).

Tare – The mass of an empty vessel used to receive a substance to be weighed.  Many balances can be tared.  That is, with the empty receiver in place, the balance can be set to read zero grams, lbs, etc.

Titrant – The substance added to the analyte in a titration.

Titration – A procedure in which one substance (titrant) is carefully added to another (analyte) until complete reaction has occurred.  The quantity of titrant required for complete reaction tells how much analyte is present.

Turn Overs Per Hour – Refers to the amount of bath flow passing through a pump and filter from the plating tank and returned.

Volt – Unit of electric potential or electric potential difference between two points.  If the potential difference between two points is one volt, it requires one joule of energy to move one coulomb of charge between the two points.

Volumetric Flask – One having a tall, thin neck with a calibration mark.  When the liquid level is at the calibration mark, the flask contains its specified volume of liquid.

QAH, W – The SI unit of power, equal to an energy flow of one joule per second.  When an electric current of one ampere flows through a potential difference of one volt, the power is one watt.

Weighing Paper – Used as a base on which to place a solid reagent on a balance.  The paper has a very smooth surface, from which solids fall easily for transfer to a vessel.

Work Item – The item to be plated.

THE WET PROCESS:

Acid Activation (pickle tank) – A suitable acid solution and type to excite work surface molecules without removing material.

Acid Etch – Acid concentration and type as to remove a small amount of work item surface.

Anodic Clean – An electro cleaning operation where the work item is attached to the positive side of the power source so as the electrical ions flow from the work item it takes soil and oxides with them.

Anodic Etch – An acid solution in conjunction with electro current in a positive condition to aggressively remove work item surface matter.

Cathodic clean – Like anodic clean, but the work item is negatively charged.

CWR – Cold Water Rinse – Work items are submerged into one area of the rinse tank and removed from another.

Electro Clean – The work item is suspended in a chemical detergent bath and the work item is attached to a D.C. current power source either positive or negative while either the steel tank itself or anodes or cathodes complete the circle.

Nickel Strike (woods nickel strike) – An acid solution containing nickel salts in conjunction with positive electro currents as to deposit a thin amount of nickel on the work item surface.

Soak Clean – A process tank containing a high level of detergent type of cleaner at elevated temperatures with circulation.