Film-forming corrosion inhibitor for carbon steel, stainless steel and copper alloys in open and closed circulating water systems.
Corrosion in a cooling system is an electrochemical process that needs water, oxygen and a bare metal surface. The practical way to interrupt it is to keep the metal covered. This inhibitor contains film-forming actives that adsorb onto metal surfaces and build a thin, tenacious barrier that slows both the anodic and cathodic reactions, so the corrosion rate falls well below what mild steel would otherwise suffer in aerated water.
Covering the general case is only part of the job. Cooling circuits contain mixed metallurgy — carbon steel shells and heads, copper alloy tubes, stainless steel plates and galvanised fittings — and an inhibitor that protects steel but attacks copper is worse than useless. The formulation therefore combines steel protection with a copper-specific component that suppresses the galvanic couple between dissimilar metals, which is where the most damaging pitting usually starts. Corrosion rate is monitored with coupons or an online probe, and the results drive the dose in the same way that residual phosphate drives the scale programme.
| Appearance | Pale yellow to amber liquid |
|---|---|
| Active content | ≥ 25% |
| Active chemistry | Film-forming amine and azole blend |
| pH (1% solution) | 7.0 – 9.5 |
| Density (20 °C) | 1.00 – 1.15 g/cm³ |
| Solubility | Fully miscible with water; forms a clear working solution |
| Dosing method | Continuous metering into the circulating line or basin |
| Packaging | 25 L cans / 200 L drums / 1000 L IBC |
| Shelf life | 12 months in unopened packaging, protected from frost |
Dose the product continuously into the circulating water with a metering pump, using a separate injection point from the scale inhibitor and the biocide. The working dose is typically 20 – 100 mg/L, but the number that matters is the corrosion rate, not the dose: monitor with mild steel and copper coupons or with an online probe, and adjust until the rate settles comfortably below your target. An initial passivation period at a somewhat higher dose is usual on a newly cleaned system, followed by a lower maintenance rate once the protective film has formed. Track pH, conductivity, chlorides and inhibitor residual alongside the corrosion data, because a rise in chloride or a drop in pH will show in the corrosion rate before it shows anywhere else.
Typical dosage. 20 – 100 mg/L continuously, with a higher initial passivation dose. Set the rate from coupon or probe corrosion monitoring.
How do I set the dose? From the measured corrosion rate, not from a rule of thumb. Install mild steel and copper coupons, or an online probe, and adjust the dose until the rates hold below your target. A higher initial dose is used on a freshly cleaned system to build the film faster.
Can it protect copper as well as steel? Yes. The formulation includes a copper-specific component, which matters wherever copper alloy tubes or brass fittings sit close to steel in the same circuit, since that is where galvanic pitting usually begins.
Can it be dosed together with the scale inhibitor? Both belong in the same programme but should be injected at separate points. Combining them at one injection point can cause localised precipitation and reduce the effect of each.
Will it cause foaming in the tower? At normal doses it does not. Foaming is more often caused by over-dosing, by contamination from process leaks, or by an anionic dispersant reacting with a cationic biocide — check the dose and the programme first.
How long does it take to work? Film-forming inhibitors build their barrier over hours to a few days depending on the dose and the water chemistry. This is why a passivation period is used on a newly cleaned system.
Is it suitable for a potable water system? No. It is intended for industrial circulating water and closed circuits. Potable systems need separately certified products.
