Action mechanism of industrial sodium hexametaphosphate in metal corrosion inhibitor

Adding a small amount of a substance in the corrosive environment can greatly reduce the corrosion rate of metals. This substance is called corrosion inhibitor, also known as corrosion inhibitor. The definition of industrial Sodium Hexametaphosphate in metal corrosion inhibitor has three meanings:

1. Slow down the corrosion of metal materials;

2. Maintain the physical and Mechanical properties of metals;

3. Use a small amount or a small amount.

Precipitation type corrosion inhibitor is a kind of corrosion inhibitor which works by forming precipitation film on metal surface. It can be divided into anode type and cathode type. The anode type includes phosphate, borate, silicate, benzoate, etc. The cathode type mainly includes salts of calcium, magnesium, zinc, manganese and nickel.

The characteristic of polyphosphate is that phosphorus oxygen bond can be hydrolyzed to produce orthophosphate ion, which is a kind of anodic corrosion inhibitor. It should be noted that when the amount of orthophosphate ion is insufficient, it is easy to produce local corrosion. The bigger harm is that when the content of calcium ion in water is high, it is easy to form calcium iodate precipitation with orthophosphate ion produced by hydrolysis, resulting in fouling.

Polyphosphate is an important corrosion inhibitor. At present, sodium hexametaphosphate is widely used in industry. Precipitation type corrosion inhibitor is often called safety corrosion inhibitor. Insufficient dosage will not increase metal corrosion.

The adsorption mechanism of industrial sodium hexametaphosphate corrosion inhibitor is that the corrosion inhibitor has adsorption on the metal surface, forming an adsorption film on the metal surface, resulting in corrosion inhibition. Its main function is to form a protective film on the cathode by electrodeposition, which has the functions of corrosion and scale inhibition at the same time.