The oxidation of small organic molecules: A survey of recent fuel cell related research

The present article focuses on the current status of research and development concerning corrosion resistance of Fe-Cr-based amorphous alloys and gives suggestions for further investigations aimed at improving the performance of these alloys and recommendations of possible new applications. These materials, which are usually obtained either as glassy bulk material or in coating and ribbon form, show high corrosion resistance and high wear resistance and are also relatively inexpensive compared to other amorphous metallic alloys. These characteristics can lead to promising applications of these alloys in which corrosion resistance and erosion-corrosion resistance are important. This review presents the results obtained in recent years, including the effect of amorphous structure, partial crystallization and composition on corrosion resistance, as well as applications of these alloys. Although advances have been made in studies concerning Fe-Cr-based amorphous alloys, there is an important limitation in terms of using them, which is the issue related to the high Mo content needed to achieve sufficient glass-forming ability and high corrosion resistance, which significantly increases the cost of these alloys. Therefore, the cost/benefit relation of these alloys needs to be improved by studying the effect of composition and structure on corrosion resistance and finding new applications of these alloys. Based on this literature review, possible applications and further investigations of these alloys are suggested.

Corrosion resistance of Fe-Cr-based amorphous alloys: An overview

X-ray photoelectron spectroscopy was applied to study the composition of the passive film formed on an extremely corrosion resistant amorphous Fe-10at.%Cr-13at.%P-7at.%C alloy in 1 N HCl. The passive film consists mainly of hydrated chromium oxyhydroxide which is a common major constituent of passive films on crystalline stainless steels. The extremely high corrosion resistance of the amorphous alloy can only in part be attributed to the formation of a protective hydrated chromium oxyhydroxide film.

ESCA Study of the Passive Film on an Extremely Corrosion-Resistant Amorphous Iron Alloy

This chapter presents a review of electrode materials used for the hydrogen evolution reactions and a comparison of their electrocatalytic activities. The introduction presents a brief definition of various thermodynamic water electrolysis potentials. In general, there are two ways to improve the performance of electrode materials: (1) use of electrode materials characterized by higher intrinsic activity i.e., higher exchange current density and (2) use of electrodes characterized by large real surface area. Both methods are used in practice. In this chapter various electrode materials are reviewed: smooth metals, alloys, intermetallic compounds and composites, Raney type materials (Raney Ni, Zn, etc.), oxides, carbides, sulfides, borides, phosphides, amorphous and nano-crystalline materials etc., Among the most active materials are noble metals, doped Raney-type alloys, IrO2/Ru2O, sulfides, borides, and Ni/Mo based alloys. Unfortunately, noble metals are very expensive and easily poisoned and their activity decreases with time. Although many materials may still be improved and optimized there is a need to study the detailed mechanism and kinetics of the HER on these materials and the relation between the geometric (surface roughness) and intrinsic electrocatalytic properties.


Keywords:

hydrogen evolution reaction;
reaction mechanisms;
Volmer–Heyrovsky mechanism;
Volmer–Tafel mechanism;
overpotential;
Tafel slope;
volcano plot;
electrode activity;
apparent;
intrinsic;
electrode materials;
metals;
alloys;
composites;
intermetallic compound;
oxides;
phosphides;
sulfides;
borides;
Raney alloys;
amorphous;
nano-crystalline;
solid polymers;
thermoneutral cell voltage;
water electrolysis–standard cell voltage

Hydrogen evolution reaction

Ultrathin passive films effectively prevent the chemical attack of stainless steel grades in corrosive environments; their stability depends on the interplay between structure and chemistry of the constituents iron, chromium, and molybdenum (Fe-Cr-Mo). Carbon (C), and eventually boron (B), are also important constituents of steels, although in small quantities. In particular, nanoscale inhomogeneities along the surface can have an impact on material failure but are still poorly understood. Addressing a stainless-type glass-forming Fe50Cr15Mo14C15B6 alloy and using a combination of complementary high-resolution analytical techniques, we relate near-atomistic insights into increasingly inhomogeneous nanostructures with time- and element-resolved dissolution behavior. The progressive elemental partitioning on the nanoscale determines the degree of passivation. A detrimental transition from Cr-controlled passivity to Mo-controlled breakdown is dissected atom by atom, demonstrating the importance of nanoscale knowledge for understanding corrosion.

https://science.sciencemag.org/content/sci/341/6144/372.full.pdf

B. H. Harji

Papers

The electrochemical properties of metallic glasses

Electrochemical Properties of Metallic Glasses