Metallic Glasses for Triboelectrochemistry Systems

Abstract

A fundamental quest of modern triboelectrochemistry is to unravel the prevailing failure mechanisms when surface interactions are operated in corrosive environments and to study how these influence the performance of materials and tools. Both system and materials oriented approaches are thus required to deal with the electrochemical and physicochemical changes of matter due to the influence of a mechanical sliding energy between the two contacting surfaces (i.e. tribocorrosion damage). In this chapter, metallic glass material concepts used in environments where tribocorrosion occurs are described. Concepts to act in opposition to wear and corrosion are briefly reported. In particular, a description is given of different groups of metallic glasses designed to withstand the effects of combined and uncoupled wear and corrosion. Metallic glass composition, structural effect, crystallization level, passive film formation, microhardness are often viewed as the most critical elements in the performance of tribocorrosion of metallic glasses. Interactions between wear and corrosion mechanisms are identified along with some models that aim to inform metallic glass selection and predict performance.

Electrochemical Techniques for Corrosion and Tribocorrosion Monitoring: Fundamentals of Electrolytic Corrosion

“…), and often modifies the environment (e.g., surface contamination by tribo-reaction products or corrosion-produced compounds, pH changes, and so on), and ultimately can lead to system failure. Such a physical-chemical deterioration is well described in the literature by the following terms: corrosive wear, fretting-corrosion or corrosion-erosion [1][2][3][4][5][6]. Corrosion and wear often combine to cause aggressive damage and at last a shutdown in a number of industries, such as mining, mineral processing, chemical processing, metal components of machines, marine structures, pulp and paper production, ships, bridges, biomechanics (e.g., orthopedics), civil engineering structures and energy production, and so on.…”

“…Corrosion accompanies to some extent in all environments, except in vacuum and inert atmospheres. The combined effects of friction (wear) and corrosion can result in total material losses well above than that of the additive effects of each process taken apart, which is attributed to their synergy [1][2][3]7]. These effects are still difficult to control.…”

“…In turn, corrosion can affect the friction (and wear) process of moving contacting parts. This usually accelerates the tribochemical degradation of the material, which may affect the contact moving conditions, and thus the friction process and the coefficient of friction too [1][2][3][4][5][6]. The contact motion can be a continuous or discontinuous one; it can be a unidirectional or a reciprocating one.…”

“…Tribocorrosion of moving solids immersed in an aggressive environment is, just as friction, a system parameter. The tribo-electrochemical system consists of implementing in-situ electrochemical techniques to a tribological designed system under well-controlled conditions (i.e., tribometer type, and complete material system) [3]. A properly designed laboratory mechanical system allows for the best simulation as much as possible the entire material system used in the field, and the constraints that have associated with it (e.g., vibration mode, similarity of the wear mechanisms active in the laboratory test and in the field, such as abrasion, adhesion, fatigue, existence or not of a third body, erosion, corrosion, their combinations, and so on) [3].…”

“…The tribo-electrochemical system consists of implementing in-situ electrochemical techniques to a tribological designed system under well-controlled conditions (i.e., tribometer type, and complete material system) [3]. A properly designed laboratory mechanical system allows for the best simulation as much as possible the entire material system used in the field, and the constraints that have associated with it (e.g., vibration mode, similarity of the wear mechanisms active in the laboratory test and in the field, such as abrasion, adhesion, fatigue, existence or not of a third body, erosion, corrosion, their combinations, and so on) [3]. Both mechanical and electrochemical methods allows for monitoring and recording in-situ and in real-time the following macroscopic quantities as normal or tangential force, relative or rotational displacement, sliding velocity, angular frequency, contact temperature, vibrations of the contacting parts and in relative motion, noise eventually emitted during the test, and the measurements of the electrochemical potential, the corrosion current and/or the impedance of the working materials.…”