Challenges in optimizing the resistance to corrosion and wear of amorphous Fe-Cr-Nb-B alloy containing crystalline phases

Influence of the Nb and V Addition on the Microstructure and Corrosion Resistance of the Fe-B-Co-Si Alloy

“…Analysis R ct for the Fe 62 Co 15 B 14 Si 9 , Fe 67 Co 10 B 12 Si 9 Nb 2 , and Fe 57 Co 10 B 20 Si 5 Nb 4 V 4 alloys obtained from fitting the EIS results in 0.5 M NaCl suggests that the addition of Nb and V had a positive influence on the final corrosion protection of fabricated alloys. Alloying Nb and V have influenced a comparatively extended protectiveness of the Fe 57 Co 10 B 20 Si 5 Nb 4 V 4 alloy in 0.5 M NaCl solution, which is in accordance with literature data [ 33 , 44 ]. Obtained results can be correlated with XRD, where the Fe 67 Co 10 B 12 Si 9 Nb 2 material shows peaks from crystalline precipitates without the amorphous halo.…”

“…The corrosion processes resulted in the complete covering of the Fe 62 Co 15 B 14 Si 9 sample surface with a film of corrosion products (Figure 13a). In addition, two levels of the film can be distinguished-the lower continuous layer and the upper one discontinuous layer composed of petals, which was also found in [33]. In the case of the Fe 67 Co 10 B 12 Si 9 Nb 2 sample, after the corrosion test, the film composed of corrosive products was also observed (Figure 13b).…”

“…Materials 2021, 14, x FOR PEER REVIEW 7 of 15 significantly porous and their composition: Growing iron oxides and iron compounds richer in oxygen, e.g., Fe(OOH)2 and FeOOH, creates rust instead of a passivation film [33]. For the Fe67Co10B12Si9Nb2 sample, the value of EOCP reached −708 mV vs. SCE after 2 h of immersion.…”

“…However, for the Fe 62 Co 15 B 14 Si 9 sample, after 30 min in immersion, a slight increase in E OCP to –645 mV vs. SCE was observed and this resulted in an increase in the layer consisting of corrosion products on the metallic surface, which is a barrier to the corrosion agent [ 32 ]. However, the corrosion product cannot provide effective protection against chloride due to being significantly porous and their composition: Growing iron oxides and iron compounds richer in oxygen, e.g., Fe(OOH) 2 and FeOOH, creates rust instead of a passivation film [ 33 ]. For the Fe 67 Co 10 B 12 Si 9 Nb 2 sample, the value of E OCP reached −708 mV vs. SCE after 2 h of immersion.…”

“…However, based on the value of characteristic parameters presented in Table 1 , it seems that the effect of alloying Nb resulted in a decrease in the kinetics of the anodic dissolution of Fe, which decreased the corrosion current density by four times and increase by one order in the magnitude of resistance polarization for the Fe 67 Co 10 B 12 Si 9 Nb 2 sample in comparison to the Fe 62 Co 15 B 14 Si 9 sample. According to the literature, alloying Nb increases the corrosion resistance due to the creation of the passivation film [ 33 ]. It seems that the addition of V additionally increases the resistance to corrosion of alloys.…”