Abstract:
The influence of Cu and Sn on the microstructure, mechanical properties, corrosion resistance, and antibacterial properties of 430L ferritic stainless steel has been investigated by using Thermo-Calc calculations, EPMA (electron probe microanalysis), TEM (transmission electron microscopy), and XPS (X-ray photoelectron spectroscopy). Vichers hardness tests, potentiodynamic polarization, and antibacterial tests were also performed. For a copper content of 1.5 wt.%, the results showed that aging treatments at 600 degrees C, 700 degrees C and 800 degrees C are conducive for the precipitation of an e-Cu phase in the 430L ferritic stainless steel. It was also found that the e-Cu phase was composed of almost pure Cu (with a the content of 98.6-99.7 wt.%). Thermo-Calc calculations showed that there was only a very small amount of Fe, Cr, and Mn in thee-Cu phase. Moreover, the e-Cu phase was found to substantially coarsen with an extension of the aging time. The size of e-Cu phase increased from a few nanometers to hundreds of nanometers, and the number of e-Cu phase decreased gradually. Furthermore, the antibacterial rate of the 2(#) (430L - 1.5 wt.% Cu) and 3(#) steel (430L - 1.5% Cu - 0.4 wt.% Sn) samples increased significantly with an extension of the aging treatment time, and the antibacterial rate of the 3(#) steel was higher than that of the 2(#) steel sample. The antibacterial rate reached as high as 91.60% and 97.37%, respectively, for an aging time of 79,200 s.
