Insight into the corrosion behaviors and mechanism of arc discharge plasma nitrided H13 steel in molten Al-Si
S.W. Men, Panpan Yang, Gobinda Gyawali, Yang Yang, Dongyang Li, Meisam Nouri, Shihong Zhang
Abstract
AISI H13 steels were nitrided via arc discharge plasma nitriding (ADPN) with various arc currents (55, 70, 85, and 100 A) at 400 °C. The surface microhardness, wear resistance, and molten Al-Si corrosion resistance of nitrided H13 steel exhibited significant enhancements. The surface microhardness and wear resistance of nitrided H13 steel were significantly improved due to the lubricity property of the ɛ-Fe 3 N phase formed on the surface and the solid solution strengthening of the α N . Meanwhile, the nitrided layer led to a change in the corrosion mechanism from dissolution to pitting. Compressive internal stresses in the nitrided layer inhibited crack formation and promoted passivation layer formation. The high-efficiency ADPN process not only yields a wear-resistant surface but also provides a potential solution for improving the corrosion resistance against molten alloys.