Potentiodynamic and potentiostatic investigation on the passivation of Fe based glassy alloys in alkaline solution

Corrosion comparison of free and roller surfaces of Fe70Si8B12Nb10 amorphous ribbon

“…The impedance of CPE is defined as: 29,30 Q = ( jω ) − n / Y 0 where ω denotes the angular frequency (rad s −1 ), j denotes the imaginary number, and Y 0 denotes the frequency independent parameter (Ω −1 cm −2 s n ), the meanings of which can be found elsewhere. 23 The fitting results and chi-square tests are summarized in Table 2 . According to previously published studies, 31–33 the Bode plot is divided into three different regions: (i) a high frequency region (10 3 –10 5 Hz) that is mainly reflected by the resistance ( R out ) and capacitance ( Q out ) of the outer passive film or corrosion products; (ii) an intermediate frequency area (10 0 –10 3 Hz) that is mainly reflected by the resistance ( R in ) and capacitance ( Q in ) of the inner passive film; and (iii) a low frequency interval (10 −2 –10 0 Hz) that is mainly reflected by the resistance ( R a ) and capacitance ( Q a ) of the electrochemical reaction at the interface between the ribbon and passive film or the ribbon and solution.…”

“…The potential range of the potentiodynamic polarization curve was from −0.8 to 1 V SCE , and the scanning rate was 1 mV s −1 . The corrosion rate (CR) of the ribbon can be obtained through the corrosion current density ( i corr ) using the following equation: 23,24 CR (mm y −1 ) = 3.28 i corr M /( nd ) M denotes the atomic weight of Fe (55.85 g), d denotes the density of Fe (7.88 g cm −3 ), and n denotes the number of electrons transferred in the corrosion reaction ( n = 2).…”

“…The potential range of the potentiodynamic polarization curve was from À0.8 to 1 V SCE , and the scanning rate was 1 mV s À1 . The corrosion rate (CR) of the ribbon can be obtained through the corrosion current density (i corr ) using the following equation: 23,24 CR (mm y…”

Newly-developed pseudo-high entropy amorphous alloys: Structure/microstructure evolution, mechanical and corrosion properties.

“…The addition of B can increase the GFA but may embrittle the alloy [44]. As stated in [9,45], Nb can improve glass forming ability, corrosion resistance, and magnetic and mechanical properties. However, the alloys of these works also presented pitting corrosion.…”

“…Since the '60s, stimulating and well-known new categories of metallic materials have been discovered, for instance, glassy [3] and, more recently, multi-principal element alloys (MPEAs) [4]. Fe-based amorphous metallic materials are expected to have interesting properties such as strength, hardness, and magnetic, as well as resistance to wear and corrosion [5][6][7][8][9]. Despite the remarkable properties' assortment, surpassing those encountered in traditional Fe-based alloys, bulk metallic glasses (BMGs) and even MPEAs are usually related to high costs due to the amounts of substantially expensive elemental constituents.…”