Effect of Microstructure on Wear and Corrosion Performance of Thermally Sprayed AlCoCrFeMo High‐Entropy Alloy Coatings

Abstract

mixed in equimolar or close to equimolar concentrations, enabling them to form a single-phase solid solution. [4] However, the formation of intermetallics together with solid solution phases was also reported for the HEAs. [5,6] The alloys exhibit an inherently high configurational entropy effect owing to compositionally complex mixing, which promotes the solid solution phases in the form of face-centered cubic (FCC) and/or body-centered cubic (BCC) phases. [6] Other core effects, such as sluggish diffusion, distorted lattice, and cocktail effect, favor HEAs to have outstanding properties, including excellent strength, [7] significant toughness, [8] and better strain hardening ability [9] with remarkable tribological characteristics, including superior wear and corrosion resistance. [6,[9][10][11] Various studies had been employed to produce HEAs by arc melting, [12,13] spark plasma sintering, [14] laser technology, [15] microwave processing, [5,16] additive manufacturing, [17,18] and thermal spraying. [19,20] Among the techniques, thermal spray manufacturing is a promising and well-established technology, which is capable of using a broad range of feedstocks (including alloys, ceramics, and polymers) for producing thick coatings for use in developing protective surface layers. [21] The impact of thermal spraying of HEA coatings on microstructure, mechanical, and wear properties has been studied previously. [22,23] For instance, Wang et al. [24] reported excellent hardness for the AlCoCrFeNi HEA coatings developed via atmospheric plasma spraying due to hard BCC and ordered B2 phases. Another study by Meghwal et al. [22] reported high hardness of around 4 GPa for AlCoCrFeNi due to the formation of Al-rich oxide phases. Still a noticeable decrease in the corrosion performance was found compared to 316L stainless steel under seawater conditions. However, the high-temperature heat source in thermal spraying can result in undesirable phase transformations, residual stresses, and oxide contaminations. [23] In addition, the oxide inclusions along with voids such as pores and cracks are detrimental for protective performance against electrochemical damage. To probe such microstructural inhomogeneities, deposition techniques that operate with low-temperature heat sources are desirable.Cold spraying is a branch of thermal spray technologies that received attention for structural repair coatings for various

Microstructure and wear behaviour of AlCoCrFeNi-coated SS316L by atmospheric plasma spray process

“…This eventually reduces the intensity of abrasive and adhesive wear which in turn reduces the SWR of the coating. The trend also reveals a gradual increase in the COF, and it decreases gradually due to the formation of MML along the surface, which acts as a protective barrier [ 58 ]. The COF of coated and annealed samples was 10.94% and 38.82% better than the coated and uncoated sample before annealing.…”

Microstructure and Dry-Sliding Wear Resistance of CoCrFeNiMoTix High Entropy Alloy Coatings Produced by Laser Cladding

“…One of the most efficient ways to solve this problem is to prepare coatings with excellent wear resistance on mechanical components' surfaces [1][2][3][4]. Currently, common surface modification technologies include thermal spraying [5,6], laser cladding [7,8], plasma spraying [9,10], magnetron sputtering [11,12], etc. Compared with other methods, laser cladding is widely favored by researchers because of the low dilution rate, fast cooling rate, high energy density, high preparation efficiency, and the ability of good metallurgical bonding of obtained coatings with substrate materials [11,12].…”

Oxidative and abrasive wear of multiphase AlSi0.75TiMnFeCux (X = 0, 0.25, 0.5) high entropy alloy under non-lubricating reciprocating motion

“…HEAs based on refractory elements have high hardness but are brittle [4,5], while others are too ductile for use in load-bearing structural and automotive parts [3]. BCC HEAs have limited application in structural parts due to their poor yield strength [6,7,10]. Similarly, FCC HEAs are not recommended for structural parts due to their high ductility and low strength.…”

“…Unlike conventional materials, HEAs are solid solution alloys made of 5 or more base elements in equimolar concentrations. These alloys exhibit a high configurational entropy that contributes to high mechanical strength [3,4], remarkable ductility [5], oxidation and corrosion resistance [6,7], and fracture toughness properties [8,9]. HEAs based on refractory elements have high hardness but are brittle [4,5], while others are too ductile for use in load-bearing structural and automotive parts [3].…”