Technical Specifications
| Property | Unit | Typical Value | Test Method |
|---|---|---|---|
| Appearance | Yellow transparent liquid | Visual | |
| Flash Point | °C | 150 | ASTM D93 |
| Density at 20 °C | kg/m³ | 1030 | ASTM D4052 |
| Viscosity at 100 °C | mm²/s | 20 | ASTM D445 |
| Acid Value | mgKOH/g | 4.1 | ASTM D664 |
| Sulfur | % | 27.5 | ASTM D4951 |
| Copper Corrosion (121 °C, 3 h) | rating | 1A | ASTM D130 |
| Solubility (mineral Group I/II/III) | % | >10 | — |
* Typical values from batch production. Batch-specific COA available on request.
Technical content reviewed by the CheMost additives team · Specifications last reviewed
Molecular Structure
Molecular structure · thiadiazole metal deactivator
2,5-Dimercapto-1,3,4-thiadiazole (DMTD) core, C₂H₂N₂S₃ — oil-soluble derivative (ash-free)
A sulfur–nitrogen heterocyclic metal deactivator built on the dimercaptothiadiazole (DMTD) ring, which chemisorbs on copper; metal-free, so it leaves no ash.
What Is the Thiadiazole Derivative Metal Deactivator (CCI61)?
CheMost-CCI61 is an oil-soluble, oxidation-resistant metal deactivator and copper corrosion inhibitor built on the 2,5-dimercapto-1,3,4-thiadiazole (DMTD) ring. It effectively inhibits the corrosion of copper — and other metals — and, with its high sulfur content (27.5%), it is especially good at stopping the corrosion of copper and yellow metals by reactive sulfur, at very low addition levels.
Copper is the metal that matters most here: dissolved copper is a powerful oxidation catalyst, and copper alloys (brass, bronze) are attacked by the active sulfur in many EP and antiwear systems. A metal deactivator works by chemisorbing onto the metal surface to form a thin barrier film that both passivates the metal against attack and stops it from catalysing oil oxidation. The DMTD heterocycle is one of the two classic routes to that protection (the other being the benzotriazole route).
CCI61 is ash-free and supplied as an easy-to-add yellow liquid, giving a copper-strip rating of 1A. Its defining strength is protecting copper in high-sulfur / active-sulfur formulations — exactly where a sulfur-carrier EP additive would otherwise attack yellow metals.
How CCI61 Works
Chemisorbs on copper
The dimercaptothiadiazole ring bonds to the copper surface, forming a tightly-held barrier film that shields the metal from corrosive attack.
Suppresses reactive-sulfur attack
The high sulfur content makes it especially effective at preventing the corrosion of copper and yellow metals by the active sulfur in EP/antiwear systems — at very low treat.
Breaks the oxidation catalysis
By sequestering surface and dissolved copper, it stops the metal from catalysing oil oxidation, so it also supports oxidation stability and spares the antioxidant reserve.
Ash-free & oil-soluble
Metal-free and fully oil-soluble, it adds no sulfated ash and blends in easily, suiting low-ash and high-sulfur formulations alike.
Metal Deactivators Compared — Where CCI61 Fits
CheMost offers both classic copper-passivation routes plus the solid benzotriazole. The table places CCI61 against them so you can pick by heterocycle, form and the system you are protecting. All figures are from each grade’s data sheet.
| Grade | Heterocycle | Form | Best for |
|---|---|---|---|
| CCI61 (this page) | Thiadiazole (DMTD), S 27.5% | Liquid, oil-soluble | Copper protection in high-sulfur / active-sulfur EP systems |
| CCI51 | Benzotriazole derivative | Liquid, oil-soluble | General copper passivation; synergy with phenolic antioxidants |
| Benzotriazole (BTA) | Benzotriazole | Solid (granules) | The pure, granular copper corrosion inhibitor / VCI |
CCI61 is the choice when the formulation carries active sulfur — its sulfur-rich thiadiazole chemistry is matched to that environment. For general copper passivation, the benzotriazole derivative is the companion route.
Applications
CheMost-CCI61 is used as the copper corrosion inhibitor / metal deactivator in formulations targeting the duties below:
Gear & industrial oils with EP
Industrial and gear oils that use sulfur-carrier EP additives — CCI61 protects the brass and bronze components from the active sulfur.
Engine oils
Copper/lead bearing protection and oxidation-catalysis control in engine oils, at very low treat.
Greases
Yellow-metal protection in greases, particularly high-sulfur EP greases where copper alloys are present.
Metalworking fluids
Copper and yellow-metal corrosion control in metalworking oils and fluids.
Finished-oil performance approvals belong to the fully formulated oil, not to an individual additive component.
Treat Rate
The data sheet specifies the product but not a per-application dosage, so the figures below are indicative, derived from the chemistry and our formulating experience — confirm the final level.
First-order estimate. Metal deactivators work at very low treat — roughly 0.02–0.5% (often below 0.1%), dosed to a copper-strip (ASTM D130) target. The data sheet notes CCI61 protects “at very low addition levels,” so a small amount goes a long way; over-treating gives little extra benefit.
CCI61 is dosed alongside the sulfur-carrier EP system it is protecting against, and works with the antioxidant package to control oxidation. The exact level depends on the copper content of the system, the sulfur level and the rest of the package.
Treat rates are indicative, not fixed dosages. CheMost can provide formulation and treat-rate support on request.
Formulating With CCI61 — Complementary Additives
Sulfur-carrier EP additives
Active-sulfur EP additives such as sulfurized isobutylene give the best load-carrying but attack yellow metals; CCI61 is the partner that lets you use them where copper alloys are present.
Ashless dithiocarbamate
In sulfur-bearing, ash-free packages the thiadiazole and the dithiocarbamate together cover copper protection and EP/antioxidancy without adding metal.
Antioxidants
By removing copper’s oxidation catalysis, CCI61 lets the antioxidant system work less hard — the two are complementary in long-life oils.
Benzotriazole derivative
Where broad copper passivation is wanted, the thiadiazole and benzotriazole routes can be combined for comprehensive yellow-metal protection.
Documentation, Qualification & Regulatory Support
Standard documentation — Certificate of Analysis (COA, per shipment), Technical Data Sheet (TDS) and Safety Data Sheet (SDS, GHS/CLP) — is provided. The full TDS is available on request rather than as a public download. Additional support is available on request:
Regulatory documentation
REACH, TSCA and country-specific market-registration documentation support available on request.
Third-party inspection
SGS / Intertek / BV pre-shipment inspection can be arranged on request.
Custom grades & packaging
Custom packaging and grades on request.
Formulation support
Metal-deactivator and treat-rate guidance from our technical team.
Packaging & Supply
CheMost-CCI61 is stocked and shipped worldwide, with a typical lead time of 1–15 days and a 36-month shelf life at ambient temperature. Samples and quotations are answered within 12 hours.
Packaging
25 kg metal drum · 200 kg metal drum.
Minimum order
By drum — contact us for your quantity.
Incoterms
FOB · CIF · EXW, to suit your freight arrangement.
Loading ports
All major Chinese ports.
Frequently Asked Questions
What is a thiadiazole metal deactivator?
It is a copper corrosion inhibitor built on the 2,5-dimercapto-1,3,4-thiadiazole (DMTD) ring. It chemisorbs onto copper to form a protective barrier film, passivating copper and yellow metals and stopping copper from catalysing oxidation. CCI61 is oil-soluble, ash-free (S 27.5%), and gives a copper-strip rating of 1A.
Thiadiazole or benzotriazole — which should I use?
Both passivate copper. The thiadiazole (CCI61) is sulfur-rich and excels at protecting yellow metals against reactive sulfur in high-sulfur EP systems. The benzotriazole derivative (CCI51) is the general copper passivator that synergises with phenolic antioxidants. They can also be combined.
Why is it good for high-sulfur formulations?
Active-sulfur EP additives deliver strong load-carrying but corrode copper and brass. CCI61’s sulfur-rich thiadiazole chemistry is matched to that environment, protecting yellow metals so you can use an aggressive sulfur carrier where copper alloys are present.
What treat rate should I use?
Metal deactivators work at very low levels — typically about 0.02–0.5% (often below 0.1%), dosed to a copper-strip (ASTM D130) target. The data sheet notes it protects at very low addition levels. The exact level depends on the copper and sulfur content of the system; our technical team can assist.
How is it supplied, and how fast can I get a sample?
It is supplied as a yellow liquid in 25 kg and 200 kg metal drums with a 36-month shelf life, and shipped worldwide. As a manufacturer and sourcing partner (Est. 2013), CheMost answers sample and quotation requests within 12 hours.