Cutting fluid corrosion inhibitors from inorganic to organic: Progress and applications

Water-based cutting fluid has a broad application area and a hundred year history, but its poor corrosion inhibition and anti-rust ability limit its further promotion. Adding corrosion inhibitors can effectively solve the above problems. However, no review papers are available on cutting fluid corrosion inhibitors, and their mechanism, suitability, and performance influencing factors have not been revealed. This article discusses cutting fluid corrosion inhibitors to fill the gaps in theoretical research and industrial applications. Inorganic matters are initially used in corrosion inhibition due to their strong oxidizing properties. Therefore, the film formation mechanism of inorganic corrosion inhibitor oxide and precipitation film is first analyzed, and the applications in corrosive medium are summarized. Given that inorganic corrosion inhibitors are not environmentally friendly and expensive, organic corrosion inhibitors are currently used as replacement. Thus, the film formation mechanism of different organic corrosion inhibitors adsorption film is analyzed, and their suitability with metals is determined. The influence of molecular structure and temperature on their corrosion inhibition effect is also studied, and the performance of inorganic and organic corrosion inhibitors is compared. However, single organic corrosion inhibitors are greatly affected by metal surface state, temperature, and immersion time. Therefore, the synergistic film formation after the compounding of organic and inorganic corrosion inhibitors is analyzed. In addition, the influence rate of concentration, molecular structure, and temperature on corrosion inhibition performance is revealed, and a matching database of corrosion inhibitor type and metal type in cutting is established. Finally, in view of the limitations of cutting fluid corrosion inhibitors, the establishment of a molecular dynamics model of corrosion inhibitor failure and accelerates corrosion and the development of general-purpose green additives based on the molecular design and physical and chemical analysis of the suitability of corrosion inhibitor and base liquid are prospected.