A review: advancements in fluoro-based polymers for aggrandizing anti-galling and wear resistant characteristics

Abstract

Galling is the surface phenomenon which involves adhesion of local contact points and creation of protrusions on the juxtaposition of surfaces owing to high friction, inappropriate tribological loading, starved lubrication and high contact pressure (~ 1000 kPa). All these factors result in severe plastic deformation varying from 8000 to 10,000 µε (ε-strain) and diffusion of materials into one another, which consequently results in fatigue wear, surface roughness, tribocorrosion and seizing up of critical parts. The aim of the review is to analyze and summarizes the issue of galling, concurrently it also deals with the novel and economical mitigation method i.e. use of fluorine based coatings e.g. PTFE, owing to their lowest friction coefficient from 0.02 to 0.2 among other solids, high stiffness, high thermal stability and non-adherent characteristics that augments the mechanical and tribological properties and concurrently protect against hostile environments that eventually upsurges the life of components.

Galling wear between ASTM 6061 aluminum and grade D2 tool steel

“…The penetration of each other into the surface topography causes the real contact area between the two materials to correspond to the apparent contact surface. 1 Roughness and porosity are therefore favorable factors for adhesion. Defining also this relationship between these materials from the chemical point of view, the electron affinity of an element can be determined by the lowest energy of the orbital unoccupied, or partially occupied of an atom, which is known as LUMO (lowest unoccupied molecular orbital).…”

“…Galling is a surface phenomenon that involves adhesion at local contact points, and this results in the creation of protrusions on the surface due to high friction, inappropriate tribological loading, insufficient lubrication and high real contact area. 1,2 Galling generally appears in various sheet metal forming manufacturing processes, such as die cutting, pressing, shearing, bent, stamping, perforated and lined. 3 In manufacturing countries galling can be seen found in several areas: Manufacture of industrial and commercial air conditioning, heating, refrigeration equipment; internal combustion engines, turbines and transmissions, mass reproduction of magnetic components, optical media and the automotive industry.…”

“…This can be achieved by fitting a two-parameter sigmoid equation to the data. The two sigmoid parameters are represented as formula (1). This formula can be modelled in a graphic form, and it represents the range of galling wear, as a statistic approximation curve to predict the behavior of galling depending on the applied stress.…”

“…Galling is a surface phenomenon that involves adhesion at local contact points, and this results in the creation of protrusions on the surface due to high friction, inappropriate tribological loading, insufficient lubrication and high real contact area. 1,2 Galling generally appears in various sheet metal forming manufacturing processes, such as die cutting, pressing, shearing, bent, stamping, perforated and lined. 3…”

Graft polymerization of methyl methacrylate on the surface of poly(ethylene‐co‐tetrafluoroethylene) using benzoyl peroxide as initiator

“…Fluorocarbon polymers possess several advantageous properties, including high heat resistance, low friction coefficient, high hydrophobicity, and weather resistance, and they can be used in various applications such as coating materials. 1 In particular, polytetrafluoroethylene (PTFE), made entirely of fluorocarbon segments, is highly resistant to radical reactions owing to its excellent chemical, electrical, and high-energy radiation resistance. 2 Poly(ethylene-co-tetrafluoroethylene) (ETFE) is a fluororesin composed of an ethylene unit and a tetrafluoroethylene unit.…”