How to screen corrosion inhibitors from various cleaning agents for copper, aluminum, and steel?
May 16, 2023
A Corrosion Inhibitor is a chemical substance or a mixture of several chemicals that can prevent or slow down corrosion when present in an appropriate concentration and form in the environment (medium). Generally speaking, corrosion inhibitors refer to substances used to protect metal surfaces. Adding trace or small amounts of these chemicals can significantly reduce the corrosion rate of metal materials in this medium.
Screening of corrosion inhibitors in various cleaning agents Cleaning agents for copper parts and copper alloys Benzotriazole, methylbenzotriazole, 2-mercaptobenzothiazole, benzimidazole, etc. are all corrosion inhibitors for copper materials, among which benzotriazole and 2-mercaptobenzothiazole are the most common. It is generally believed that nitrogen on BTA molecules and sulfur on MBT molecules form coordination bonds with Cu (I) due to their lack of shared electron pairs. BTA has the highest adsorption on Cu below 20 ℃, and is most easily adsorbed on 90Cu-10Ni above 25 ℃. The increase in temperature is beneficial for the adsorption of MBT on 70Cu-30. In addition to the common corrosion inhibitors mentioned above, some amides, carboxylic acids, phosphate esters, etc. can also be used. The use of corrosion inhibitors should be selected based on different systems. A single corrosion inhibitor is always not as effective as a composite corrosion inhibitor. Cleaning agents for active metals such as aluminum, magnesium, zinc, 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 commonly used as 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, anti rust oil is used for brushing or spray drying, in order to prevent the substrate from rusting and achieve corrosion inhibition effect. In the design of cleaning agent formula, we first need to determine the corrosion inhibition principle of the corrosion inhibitor based on the properties of the substrate and the operating conditions. Based on the corrosion inhibition principle, we choose the type of corrosion inhibitor, and at the same time, select the appropriate corrosion inhibitor according to the environment of the formula system. Then, based on the selected corrosion inhibitor, we determine the experimental plan and conduct corrosion inhibition comparative tests to screen the corrosion inhibitor with the best corrosion inhibition performance, Finally, the optimal amount of corrosion inhibitor was determined through orthogonal experiments.
