ZDDP & Antiwear Additives

Browse CheMost ZDDP & Antiwear Additives

Start with the product family that best matches your formulation target. Each product page goes deeper into the exact grade, properties, and documentation.

Zinc Dialkyldithiophosphate (Primary Alkyl)

Multifunctional primary-alkyl zinc dialkyldithiophosphate (ZDDP) antiwear additive — antiwear, antioxidant and corrosion protection for engine, hydraulic and gear oils and greases, in a standard (SPZS-S1) and a long-chain, hydrolytically stable (SPZS-L1) grade.

Zinc Dialkyldithiophosphate (Primary-Secondary Alkyl)

Primary-secondary alkyl zinc dialkyldithiophosphate (ZDDP) antiwear additive (SPZS-M1) — a C3-secondary plus C4/C8-primary mix with rapid water separation and hydrolytic stability, the main antiwear agent for hydraulic and industrial oils.

Why ZDDP Matters as an Antiwear Additive

Zinc dialkyldithiophosphate (ZDDP) is the most widely used antiwear additive in the lubricant industry — in continuous service for more than fifty years across engine oils, transmission fluids, hydraulic fluids, gear oils and greases — because one low-cost molecule does three jobs at once: antiwear protection, mild extreme-pressure activity, and oxidation and corrosion inhibition.

How the film works: under boundary and mixed lubrication — the moments when the oil film thins enough for surface asperities to touch — ZDDP decomposes at the hot contact and grows a layered, self-renewing tribofilm: an iron-sulfide anchor against the metal, a load-bearing zinc/iron polyphosphate “glass” layer (typically 50–150 nm thick) that shears in place of the metal, and an outer organic layer that keeps the film oil-compatible. As rubbing removes the film, fresh ZDDP in the bulk oil rebuilds it, so wear protection regenerates until the additive depletes — which is why drain interval tracks ZDDP depletion.

ZDDP rarely works alone. It is balanced against detergents and ashless dispersants in every crankcase package, and pairs with organomolybdenum friction modifiers (MoDTC / MoDTP) that cut friction and help formulators hold phosphorus down where modern specifications demand it.

The CheMost ZDDP Range

CheMost supplies ZDDP in two chemistries — a primary-alkyl grade for engine oils and a primary-secondary alkyl grade for hydraulic and industrial oils. Both are high-zinc, high-phosphorus antiwear additives; the alkyl structure sets how fast the film forms and how the grade is positioned.

How to Choose the Right ZDDP

Four variables decide which ZDDP fits a formulation — alkyl type, alkyl chain length, the phosphorus budget and system compatibility. Work through them against your target oil:

• Primary vs primary-secondary alkyl: primary-alkyl ZDDP gives the best thermal and hydrolytic stability and is the default for engine oils — CheMost offers it as the standard SPZS-S1 and long-chain SPZS-L1. A primary-secondary grade (SPZS-M1) adds a C3 secondary component for faster, lower-temperature film formation and rapid water separation, which is what hydraulic and industrial oils need. Match the chemistry to the fluid: engine oil → primary; hydraulic / industrial → primary-secondary.
• Alkyl chain length and volatility: within the primary class, the long-chain SPZS-L1 is more stable at high temperature and far more resistant to hydrolysis than the standard SPZS-S1; short alkyl groups are more volatile and less oil-soluble. Match the chain length to your operating temperature and water-exposure risk.
• Phosphorus & SAPS budget: phosphorus from ZDDP is capped by modern specifications — around 0.08 wt% (800 ppm) for API SP and ILSAC GF-6/GF-7 passenger-car oils, roughly 0.06 wt% for low-SAPS ACEA C1/C2, and higher for heavy-duty diesel — because excess phosphorus can poison exhaust catalysts. At 7.2% phosphorus, a 1.0 wt% treat contributes about 720 ppm; calculate the contribution before fixing the dose, and supplement with ashless antiwear and organomolybdenum where the limit is tight.
• Application severity: engine and hydraulic oils use modest treat rates; gear oils and greases run higher and usually pair ZDDP with a sulfurized-olefin EP additive for the heaviest loads.
• Compatibility — soft metals: ZDDP attacks silver and some copper alloys and can damage axial-piston pumps at sliding steel–copper interfaces. Systems with silver-plated bearings or silver-bearing components must avoid ZDDP and use an ashless antiwear instead — a substitution, not a treat-rate adjustment.

Common Applications

• Engine oils (PCMO & heavy-duty diesel): valve-train, cam/follower and ring/liner wear protection plus oxidation control; typically around 1.0–3.0 wt%, with the upper end limited by the phosphorus cap.
• Antiwear hydraulic fluids: vane- and piston-pump antiwear and oxidation stability — the long-chain grade suits water-exposed systems; avoid ZDDP in silver-containing axial-piston systems.
• Industrial & gear lubricants: antiwear plus mild EP, usually with a sulfurized olefin in gear oils for the heaviest loads.
• Lubricating greases: antiwear and EP for high-load and EP greases, around 0.5–3.5 wt%.
• Marine & stationary engine oils: wear and corrosion protection alongside a high-TBN detergent package that neutralises high-sulphur-fuel acids.

Quick Reference