Metal materials are vulnerable to corrosion in the process of production and service, which often leads to serious disasters, including the decline of the performance of metal components and the shortened service life, and even causes catastrophic accidents and ecological damage. Adding a certain amount of corrosion inhibitors (CIs) to the corrosive medium is a simple, efficient, and economical anti-corrosion method to slow down and restrain the corrosion of metal materials. Organic corrosion inhibitors (OCIs) are considered to have good application prospects and are widely used for surface anti-corrosion of metal materials, as they generally have advantages such as good metal adsorption, low oxidation resistance, good thermal and chemical stability, and green environmental protection. This paper systematically summarized some major OCIs, including alkyl chains, imidazoles, and pyridines, and their structural characteristics, as well as the action mechanism of OCIs. Moreover, this paper discusses some natural compounds used as environmentally friendly CIs and provides a prospect for the development trend of OCIs.

Heat treatment plays a decisive role in the microstructure of metallic materials. The effect of cooling rate changes caused by the quenching medium on the microstructure of steel materials should be clarified. In this study, the effect of the quenching cooling rate on the microstructure of two precipitation-hardened martensitic stainless steels was investigated. The mechanical properties and hydrogen embrittlement susceptibility effected by the changes in the microstructure were also analyzed. A slow tensile test and hydrogen pre-charging were carried out to obtain the hydrogen embrittlement susceptibility parameters of the specimens. The results show that the quenching cooling rate only affects specific microstructures, including the twin structure and misorientation angle. Before hydrogen charging, the mechanical properties of the precipitation-hardened martensitic stainless steels were not affected by changing the quenching cooling rate. After hydrogen charging, the hydrogen embrittlement susceptibility decreased as the quenching cooling rate increased.