How to screen corrosion inhibitors among various cleaning agents for copper aluminum steel?
January 25, 2023
Corrosion Inhibitor is a chemical substance or a mixture of several chemical substances that can prevent or slow down corrosion when it exists in the environment (medium) in an appropriate concentration and form. Generally speaking, corrosion inhibitors refer to those substances used for metal surface protection. Adding a small amount or a small amount of such chemicals can significantly reduce the corrosion rate of metal materials in this medium.
Selection of corrosion inhibitors in various cleaning agents Copper parts and copper alloys Benzotriazole, methylbenzotriazole, 2-mercaptobenzothiazole, benzimidazole, etc. are all corrosion inhibitors for copper materials, of which benzotriazole and 2-mercaptobenzothiazole are the most common. It is generally believed that the nitrogen on BTA molecule and the sulfur on MBT molecule form a coordination bond with Cu (I) with their non shared electron pairs. BTA is most easily adsorbed on Cu below 20 ℃ and 90Cu-10Ni above 25 ℃. The increase of temperature is beneficial to the adsorption of MBT on 70Cu-30. Apart from the above common corrosion inhibitors, some amides, carboxylic acids, phosphate esters, etc. can also be used. The use of corrosion inhibitors should be selected according to different systems. A single inhibitor is always less effective than a compound inhibitor. Aluminum, magnesium, zinc and other active metals and their alloys Active metals often use some gel adsorption substances for corrosion inhibition, such as sodium tripolyphosphate and sodium metasilicate, which are cheap and widely available. In addition, some phosphate esters and amphoteric imidazolines will be used. Due to the wide application of active metals in the market, corrosion inhibition is difficult, many manufacturers have launched a series of composite corrosion inhibitors for this situation. In steel cleaning agents Inorganic corrosion inhibitors, such as nitrite, chromate, thiourea, and urotropine, are common corrosion inhibitors for steel in the market. They can also be used in the form of coating, such as phosphating film, ceramic film, or other coatings. In some fields, in order to increase the storage time of the substrate, antirust oil is used for painting, or spray paint is used for drying, so as to prevent the substrate from rusting and achieve the effect of corrosion inhibition. In the formulation design of the cleaning agent, we first need to determine the corrosion inhibition principle of the inhibitor according to the properties of the substrate, combined with the operating conditions, select the type of inhibitor according to the corrosion inhibition principle, and select the appropriate inhibitor in combination with the environment of the formulation system. Then, according to the selected inhibitor, we need to determine the experimental scheme and carry out corrosion inhibition comparison tests to screen out the inhibitor with the best corrosion inhibition performance, Finally, the optimal addition amount of corrosion inhibitor was determined by orthogonal test.
