Analysis of Corrosion and Wear Performance of the Automatic Mechanism in Automatic Rifles under Simulated Marine Atmospheric Environment

• Study on the Corrosion and Wear Performance of Automatic Mechanisms in Rifles • Corrosion accelerates the occurrence of wear. • The rust layer may either inhibit or promote wear during the abrasion process. • The protective effect of rust layers during the corrosion process is limited. This study investigates the corrosion and wear of the automatic mechanism in automatic rifles servicing in marine atmospheres. Taking 25Cr3Mo3NiNbZr steel as the research subject, neutral salt spray testing was employed to simulate the marine atmospheric environment. Integrated with electrochemical measurements, tribological tests, and characterization techniques including SEM and XRD, a systematic analysis was conducted on its corrosion-wear performance. The results show that the corrosion current density increased while the polarisation resistance decreased, indicating a progressive degradation in corrosion resistance. The wear behaviour was significantly influenced by pre-corrosion. Compared to uncorroded samples, the corroded specimens exhibited a higher average friction coefficient and an increased wear rate. The corrosion-induced rust layer played a dual role in the wear process: initially, it promoted abrasive wear by spalling off, whereas in later stages, the thickened rust layer helped mitigate material damage. However, due to its porous and poorly adherent structure, the rust layer suffered from severe spalling, which progressively led to increased material loss.