摘要
The effects of Cl ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel（UHSMSS） were investigated by a series of electrochemical tests combined with observations by stereology microscopy and scanning electron microscopy. A critical Cl- ion concentration was found to exist（approximately 0.1wt%）, above which pitting occurred. The pitting potential decreased with increasing Cl- ion concentration. A UHSMSS specimen tempered at 600°C exhibited a better pitting corrosion resistance than the one tempered at 400°C. The corrosion current density and passive current density of the UHSMSS tempered at 600°C decreased with increasing pH values of the corrosion solution. The pits developed a shallower dish geometry with increasing polarization potential. A lacy cover on the pits of the UHSMSS tempered at 400°C accelerated pitting, whereas corrosion products deposited in the pits of the UHSMSS tempered at 600°C hindered pitting.
The effects of Cl ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel（UHSMSS） were investigated by a series of electrochemical tests combined with observations by stereology microscopy and scanning electron microscopy. A critical Cl- ion concentration was found to exist（approximately 0.1wt%）, above which pitting occurred. The pitting potential decreased with increasing Cl- ion concentration. A UHSMSS specimen tempered at 600°C exhibited a better pitting corrosion resistance than the one tempered at 400°C. The corrosion current density and passive current density of the UHSMSS tempered at 600°C decreased with increasing pH values of the corrosion solution. The pits developed a shallower dish geometry with increasing polarization potential. A lacy cover on the pits of the UHSMSS tempered at 400°C accelerated pitting, whereas corrosion products deposited in the pits of the UHSMSS tempered at 600°C hindered pitting.
基金
financially supported by the National Natural Science Foundation of China (No.51171023)
the Fundamental Research Funds for the Central Universities (No.FRF-TP-14-011C1)
the Major State Basic Research Development Program of China (No.2014CB643300)
