The corrosion inhibition effect of the corrosion inhibitor is closely related to its concentration and the pH value, temperature and flow rate of the medium. Therefore, it should be strictly selected according to the object to be protected and environmental conditions. The environmental pollution that corrosion inhibitors may cause has attracted attention, and attention to the selection of corrosion inhibitors has shifted to types that do not contain heavy metals. Depending on the situation, special corrosion inhibitors can sometimes be used. For example, vapor phase corrosion inhibitors were developed during the Second World War and used in the shipment and storage of metal equipment. They are substances with a certain volatility, can exist in the wet film on the metal surface, and have strong adsorption properties, such as dicyclohexylammonium nitrite, which are generally made into tablets or impregnated on packaging paper.
Polyphosphate is often used in industrial circulating water. Although the amount of corrosion inhibitor is 0.1% to 1%, as industrial water, because of the large amount of water, the amount of P discharged into the water environment is still considerable, and a large amount of P If it enters the water body, it is very easy to cause the problem of eutrophication of the water body. Therefore, other more effective methods must be used for industrial descaling and anti-scaling.