Corrosion inhibitor processes with controlled pH

Unlike the first two protection processes discussed above, these consist in  

Most of these inhibitors have a binary compound base that enables them to block die corrosion anodes and cathodes at the same time. They act directly on electrochemical 

The presence of at least a minimum of calcium hardness (10 to 20 mg l ) is generally advisable to promote the formation of the protective film. 

Additionally, one of the most common binary elements is zinc. In order to remain available in the vicinity of the walls, it requires a pH close to neutral or just slightly acid in the system water, depending on the formulation. 

Reagent doses of several dozen mg l are sufficient because both the cathodic and anodic processes are under control. (Meanwhile, solely anodic inhibitors require much larger amounts, about one g-l , to prevent pitting. This is why they are mainly used in closed systems where there is no water loss.) 

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