Benzotriazole (BTA) Corrosion Inhibitor Supplier South Africa

What Is Benzotriazole?

Benzotriazole (BTA, 1H-benzotriazole) is an aromatic heterocyclic compound — a white crystalline solid that is moderately soluble in water. It is the most widely used and most effective corrosion inhibitor for copper and copper alloys (brass, bronze, cupronickel) in aqueous systems. BTA works by chemisorption: the nitrogen atoms of the triazole ring coordinate directly to the copper surface to form an insoluble, highly stable Cu(I)-BTA polymer complex that acts as a physical barrier preventing further oxidation of the copper surface by dissolved oxygen, chlorine, or other oxidants. This protective film is extremely thin (molecular monolayer) but extraordinarily effective, reducing copper corrosion rates by 95–99% at dosages as low as 1–5 mg/L.

Cooling Water and Heat Exchanger Application

In cooling water treatment programmes, copper and brass alloy heat exchangers, condensers, and piping are the most corrosion-vulnerable components. Dissolved oxygen, chlorine, pH swings, and velocity-induced erosion-corrosion all attack copper surfaces. BTA is dosed at 1–5 mg/L in the recirculating cooling water as part of the corrosion inhibitor blend. It forms a persistent Cu-BTA film on all copper alloy surfaces in the system — the film persists through pH 6–10 and temperatures up to ~80°C. BTA is compatible with molybdate, zinc, polyphosphate, and azole-based corrosion inhibitor formulations, and is the industry-standard yellow metal inhibitor in all formulated cooling water corrosion inhibitor programmes.

Other Industrial Applications

Beyond cooling water, benzotriazole is used in metalworking fluids (cutting oils, grinding fluids) as a copper corrosion inhibitor and as a vapour-phase corrosion inhibitor component. In anti-freeze/coolant formulations (automotive and industrial glycol coolants), BTA is the standard copper corrosion inhibitor component. In industrial lubricants, BTA is added to hydraulic oils, gear oils, and turbine oils in contact with copper alloy bearings or heat exchangers. In electronics, BTA is used as a copper surface protection agent in printed circuit board manufacturing processes. Terracore Chemicals supplies benzotriazole in powder form (25 kg bags) and as concentrated aqueous solution for cooling water treatment programmes across Southern Africa.