The inhibition behavior of the promising eco-friendly inhibitor 8-hydroxyquinoline (8HQ) in two concentrations of sodium chloride solution was studied by hydrogen evolution, scanning electron microscope (SEM), three-dimensional morphology, electrochemical testing, and computational calculations. The results indicated that the 8HQ inhibitor showed satisfactory inhibition effect due to its fast, excellent adsorption capacity and self-healing ability. The corrosion inhibition effect is related to the concentration of the inhibitor. There was a competitive adsorption relationship between 8HQ and [Cl⁻], and the adsorption morphology was obviously affected by the concentration of [Cl⁻]. At the lower concentration of NaCl solution, the adsorption of 8HQ was more orderly, faster, and the adsorption amount was larger, which led to the formation of a denser protective layer. Density functional theory (DFT) results showed that the most stable adsorption configuration of 8HQ was NO-Top. N and O atoms are the active sites, and there is a strong coupling between them and Mg atoms, which is consistent with the experimental results.

This study evaluated the damage behavior of 321 austenitic stainless steel under tensile loading by measuring its magnetic properties. The results indicate that, at room temperature, the magnetic properties of 321 stainless steel respond distinctly to mechanical loading. Changes under external stress are primarily attributed to the phase transformation from austenite to martensite. Both coercive force and magnetic Barkhausen noise effectively characterize this material’s deformation and phase transformation processes: the coercive force dynamics curve exhibits an initial rise, followed by a decline with a decrease during the specimen’s necking stage. Magnetic Barkhausen noise is highly sensitive to stress changes, especially during the elastic stage. In situ measurements show that, at a stress of 300 MPa, the magnetic Barkhausen noise peak voltage signal reaches 0.060 V, which is a 100.0% increase compared to the original specimen (0.030 V). Therefore, when assessing the stress state and damage of stainless steel using coercive force and magnetic Barkhausen noise techniques, attention should be paid to the inflection characteristics of the coercive force dynamic curve and the inflection points in the peak values of the magnetic Barkhausen noise voltage signal. These features can be used to effectively monitor crack initiation and propagation in austenitic stainless steel.