A Study on Tantalum Alloying Layer and Its Performance on the Surface of 316LSS in Harsh Environments

Tantalum diffusion layers were fabricated on 316L stainless steel substrates using the double glow plasma surface alloying technology (DGPSAT). The optimization rules of the Fe-Ta diffusion layer under varying alloying times were investigated, focusing on the effects of processing parameters on the phase structure and microstructure. The results indicate that, as the alloying time increases, the surface wrinkled structure in the Fe-Ta alloy layer gradually transforms into a nanoscale acicular α-Ta structure, improving surface roughness and water contact angle. The surface microstructure influenced by the alloying time enhanced mechanical properties significantly, increasing Vickers hardness from 152 HV0.2 to 970 HV0.2, improving bonding strength, and reducing the friction coefficient to 0.5. Electrochemical testing showed that the corrosion rate of the tantalum diffusion layer was significantly reduced from 1.04 × 10−2 mm/a to 2.83 × 10−4 mm/a, demonstrating the excellent corrosion resistance. The island growth pattern during the formation of alloy layers was simulated by molecular dynamics. Replacing bulk materials with tantalum diffusion layers can economize rare metals, reduce costs, and be of great significant for the special equipment applications in harsh environments.