Thirty-five key lubricant additive terms defined the way a working chemist would use them. Bookmark this page for quick reference.
A
Antiwear AdditiveAW
Additive that protects metal-on-metal contact under boundary lubrication by forming a sacrificial reaction film on the iron surface. Dominant chemistry is ZDDP.
AntioxidantAO
Slows oxidative degradation of base oil. Phenolic AO and aminic AO are typically used in synergistic combination.
Ashless Dispersant
Dispersant containing no metallic atoms — typically PIBSA-PAM succinimides. Standard chemistry for modern engine oils.
ASA (Alkenyl Succinic Acid)ASA
Ferrous-metal corrosion inhibitor used in industrial oils and greases. Treat 0.05–0.3 % typical.
B
Base Oil
The hydrocarbon (or synthetic) fluid that constitutes 75–95 % of a finished lubricant. Classed into API Groups I, II, III, IV (PAO), V (esters & others).
BIS IS 13656
Bureau of Indian Standards specification for engine oils — defines minimum performance requirements for the Indian PCMO and HDD market.
C
Calcium Sulfonate Detergent
Overbased calcium-based detergent used in engine oils for acid neutralization. TBN typically 300, 400, or 500 mg KOH/g.
COA (Certificate of Analysis)COA
Lot-specific document listing measured values for key parameters. Issued with every additive shipment.
Corrosion InhibitorCI
Protects metallic surfaces from chemical attack. Targeted variants exist for ferrous metals (ASA) and yellow metals (triazole).
D
Dispersant
Keeps soot, oxidation products, and combustion residue suspended in the oil so they don't form deposits. Workhorse chemistry: succinimide (PIBSA-PAM).
DI PackageDI
Detergent-Inhibitor package — a pre-blended additive system for a specific finished-oil category (e.g. PCMO, HDD, MCO).
Demulsifier
Promotes rapid separation of water from oil — important for hydraulic, turbine, and gear oils.
Drop Point
Temperature at which a grease becomes fluid enough to drop from a test apparatus. Indicates upper service temperature.
E
EP Additive (Extreme Pressure)EP
Sulfur-phosphorus chemistry that protects gear teeth and shock-loaded contacts by forming a reaction film. GL-4 (mild) and GL-5 (heavy) are common calibrations.
Ester (Group V)
Synthetic base oil with high polarity. Used in high-performance and biodegradable lubricants.
F
Foam Inhibitor
Silicone or non-silicone polymer that suppresses air entrainment in the bulk oil. Dosed at very low treat rates (3–30 ppm).
Friction ModifierFM
Reduces friction in mixed and boundary lubrication regimes. Molybdenum dithiocarbamate (MoDTC) and glycerol mono-oleate (GMO) are common.
FZG Test
German gear oil test (DIN 51354) that measures fail-load stage on FZG gear rig. Critical performance measure for gear oils.
G
GL-4 / GL-5
API gear oil categories. GL-4 is calibrated for manual transmissions with brass synchros; GL-5 is more aggressive, for hypoid axles.
GMO (Glycerol Mono-Oleate)GMO
Ashless friction modifier used in passenger car engine oils for fuel economy benefits.
H
HTHS ViscosityHTHS
High Temperature High Shear viscosity. Measured at 150 °C in a tapered bearing simulator. Key engine oil performance parameter.
HEESHEES
Hydraulic oil category — biodegradable synthetic ester base. Used in environmentally sensitive applications.
I
IBC (Intermediate Bulk Container)IBC
Reusable 1000-litre composite container for bulk liquid shipment.
M
MoDTC (Molybdenum Dithiocarbamate)MoDTC
Organic molybdenum friction modifier. Adds significant fuel-economy benefit at low treat rates. Common in modern PCMO.
MSDS / SDSSDS
Material Safety Data Sheet (UN GHS 16-section format). Mandatory document for chemical shipment and handling.
MoS2
Molybdenum disulfide — solid lubricant additive used in greases and high-load lubricants.
O
OCP (Olefin Copolymer)OCP
Common viscosity index improver polymer. Lowest cost per VI unit; moderate shear stability.
Overbased Detergent
Detergent that carries excess base (alkalinity) in the form of carbonate micelles, used to neutralize acidic combustion products.
P
PAO (Polyalphaolefin)PAO
Group IV synthetic base oil — excellent VI, oxidative stability, and low-temperature performance.
PMA (Polymethacrylate)PMA
Polymer used as viscosity index improver and pour point depressant. Higher cost than OCP, better shear stability.
PPD (Pour Point Depressant)PPD
Wax-crystal modifier that lowers the temperature at which an oil ceases to flow. Critical for cold-climate operation.
R
REACH
European Union chemical regulation. Importers must pre-register chemical substances above defined volume thresholds.
RPVOTRPVOT
Rotating Pressure Vessel Oxidation Test (ASTM D2272). Measures oxidation life of turbine and circulating oils.
S
Succinimide Dispersant
Ashless dispersant — PIBSA-PAM family. Mono, bis, and borated variants tuned for different soot loads.
Shear Stability IndexSSI
Measure of how much a VII polymer breaks down under shear stress. Lower SSI = more shear-stable.
T
TBN (Total Base Number)TBN
Measure of alkaline reserve in an engine oil — primarily from overbased detergent. Expressed in mg KOH/g.
TDS (Technical Data Sheet)TDS
Document listing typical performance properties of an additive or finished lubricant.
Tackifier
High-molecular-weight polymer (typically PIB) added to greases and chain lubricants to resist wash-out and centrifugal flinging.
V
VII (Viscosity Index Improver)VII
Polymer that reduces oil viscosity sensitivity to temperature. Three common chemistries: OCP, PMA, star polymer.
Z
ZDDP (Zinc Dialkyldithiophosphate)ZDDP
Workhorse anti-wear additive for engine oils. Primary, secondary, and mixed-alkyl chemistries — different activation temperatures and surface reactivity.
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