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The cold spray (CS) process is an advanced material deposition method that has emerged as a versatile method to create high-performance coatings and functional components. This process offers unique advantages in achieving exceptional material adhesion and properties without needing high-temperature melting or heating. The CS process enables the deposition of cermets, allowing it to combine the favorable properties of their constituent phases. This review article explores the bonding mechanism specific to the CS deposition of cermets, highlighting its contrast with that of pure metals. It subsequently investigates the pivotal role played by ceramic particles in the overall efficiency of the CS deposition process, emphasizing the need for a comprehensive understanding of particle properties to achieve quality coatings for specific applications. The paper explores the challenges and limitations imposed by the CS process of cermets in optimizing the crucial parameters. It dissects the influence of interfacial bond strength and porosities on the tribological and corrosion properties of CS-deposited coatings. The discussion extends to the significant role played by substrate in shaping the coating's characteristics. The potential for enhancing coating properties through post-processing treatments is also thoroughly examined. The review article also discusses current advancements in the field and contemplates potential future directions, offering a comprehensive exploration of CS deposition of cermets and its multifaceted considerations. [ABSTRACT FROM AUTHOR]

The present work reports the utilization of laser treatment for the structuring of a B2O3 coating on ceramic substrates. The two ceramic substrates, pure Al2O3, and Al2O3-20wt% B2O3, were prepared in-house using cold pressing and sintering route. The coatings were prepared by applying the ethanol-B2O3 slurry on the ceramic substrate using a dip coater followed by drying at 100 °C. The dried coatings were subjected to the continuous laser at 22, 29, and 36 W of laser power to achieve the final coating. Coating characterization by X-ray diffraction (XRD) revealed the importance of laser power on controlling the phases of B2O3, which are H3BO3, HBO2, and amorphous B2O3. The crystallinity index (CI) of the coatings calculated using XRD spectrum decreased with an increase in laser power. The coating processed at 36 W showed the lowest CI that reveals higher amorphous B2O3 content. Sliding tests conducted in a controlled humid environment at three sliding velocities suggested a direct relationship between tribological performance and CI value—coating with lower CI value provided consistent lower COF. Additionally, a strong influence of the substrate on tribological performance was also observed—the coatings on the Al2O3-20wt%B2O3 substrate performed superior compared to the coating on the pure Al2O3. The effect of substrates is discussed in terms of thermal conductivity to achieve higher amorphous B2O3 content and the initial surface roughness of the substrates. [ABSTRACT FROM AUTHOR]

Graphene is an attractive material for many applications due to excellent inherent properties such as lower density, high mechanical strength, higher thermal conductivity, etc. However, it has been used as an additive material due to size limitation. To overcome the size limitation without affecting the inherent properties of 2D graphene sheets, researchers have developed graphene aerogel (GA) by different synthesis techniques. GA has become an emerging light-weight structure in the group of aerogel materials because of various applications. In this review article, the mechanical properties of GA have been discussed by considering the structural parameters of GA, such as pore size, graphene sheet alignments, and wall thickness, because the mechanical performance of the GA is an important criterion prior to its application in any field. It has also been highlighted that the structural parameters can be altered during synthesis to achieve desired mechanical properties. Applications of GA have been thoroughly discussed in the field of polymer composites and how GA-polymer structures can help to generate a cleaner environment by separating spilled oil from water and removing organic pollutants from water. In addition, potential of GA for various other applications with suitable nano material additives have been highlighted. [ABSTRACT FROM AUTHOR]

3D printing in the textile and fashion industry is a new emerging technology. Applications of 3D printing for designing clothes and other wearable accessories require tribological and biological understanding of 3D printing plastics against the complex human skin to mitigate skin-friction related ailments such as calluses and blisters. This study provides tribological insight in search of an optimal 3D printable material that has minimal friction against the skin. Two low friction 3D printable materials, thermoplastic polyurethane (TPU) and polyamide (TPA) were chosen and tribological testing was carried out against a water responsive skin model. The skin model was synthesized using a gelatine based model made with cotton and crosslinked with glutaraldehyde. Tribological testing of TPU/TPA against the skin model in dry and wet conditions were made. The higher coefficient of friction (COF) was observed in the wet condition compared to the dry condition. To overcome the higher friction, TPA/TPU-sodium polyacrylate composites were prepared by heat pressing that significantly reduced COF of TPU and TPA by ∼ 40% and 75%, respectively, in wet conditions. [ABSTRACT FROM AUTHOR]

Fly ash (FA) is one of the particulate wastes generated during combustion of coal in thermal power plants. Around 110 million tons of FA is generated in the USA every year, and 60% of it is deposited in landfills. Utilization of FA can create value for this waste material and also help the environment. FA is essentially a mixture of metal oxides that can be used as a filler reinforcement in metal and polymer composites. FA as a filler material reduces the amount of metals and polymer, reducing embodied energy. Hollow FA particles, called cenospheres, can provide the advantage of low density in composites as well as higher hardness and strength. FA also reduces the coefficient of thermal expansion. This article provides a brief review to capture the state of the art on the mechanical and tribological behavior of composites reinforced with FA to identify the possible benefits of using this waste material. The corrosion performance of metal matrix FA composites is also explored. Future perspectives in this field are discussed based on the potential applications of FA-filled composites. [ABSTRACT FROM AUTHOR]

This paper presents a study of corrosion behavior of electrodeposited Ni, Ni-Al2O3, Ni-ZrO2, and Ni-graphene (Gr) coatings in moist SO2 environment. Nanocomposite coatings were deposited on steel substrate by pulse electrodeposition technique with an average thickness of 9 ± 1 μm. Coatings were characterized by using nanoindentation and scratch tests to measure their mechanical properties prior to conducting corrosion tests. The corrosion resistance of coatings was evaluated according to G87–02 Method B, employing SO2 cyclic spray in the presence of moisture followed by drying. The results indicated that the addition of nanoparticles is beneficial both for enhancing mechanical properties and improving the corrosion resistance of these coatings. Higher surface corrosion resistance was observed for Ni-Gr coating. Corrosion behavior of coating was also quantified by open circuit potential measurement in 0.5 M H2SO4 environment. The results suggest that the nanocomposite Ni coatings have improved corrosion resistance compared to pure Ni coating. This work will bring significant impacts in terms of industrial applications such as architectural, automotive, and marine industries in the presence of S-pollutants because it can cause corrosion either due to acid rain or by the reaction of moisture with dry deposition of sulfur. [ABSTRACT FROM AUTHOR]

This paper presents a review of recent research inventions in the field of supersonic particle deposition (SPD) additive manufacturing (AM) technology. The SPD, also known as cold spray, is a coating technique that has gained popularity recently because of its ability to apply multi-component coatings. The SPD has the potential to revolutionize the global parts manufacturing and logistics landscape. The state-of-the-art, rapidly emerging cold spray manufacturing technology is an alternative to traditional additive manufacturing (AM) based on powder melting. It enables the rapid fabrication of parts that have properties similar to the parts developed by conventional manufacturing. In this paper, the history and process of SPD are explained. A broad background of metallic SPD AM is provided. SPD parameters, including substrate and particle properties, are discussed. Common challenges in creating consistent SPD coatings as well as challenges specific to metal and ceramic SPD are discussed. This paper explores the material science, processes, and performance gain. Several applications of SPD, including nuclear, aerospace, and electrical industries, are discussed. [ABSTRACT FROM AUTHOR]

In recent years, various solar cells have been developed that have involved silicon wafer-based systems, and various thin films. Solar cell efficiency highly depends on the surface characteristics of the solar cells. Other than efficiency, reflectivity and scattering depends on the surface parameters. In this review article, various synthesis techniques for solar cells are discussed that include vacuum-assisted and non-vacuum techniques. Surface characteristics, such as surface roughness and textures developed during synthesis or by chemical etching and lithography techniques, are discussed that affect the solar cell performance. The article highlights the importance of surface engineering for solar cells that can guide the building of multifunctional composite films for self-cleaning, antireflective, antifogging and invisibility cloak coating. [ABSTRACT FROM AUTHOR]

Triboluminescence is the spontaneous emission of light that results from the mechanical force applied to certain materials. This spontaneous light emission has been observed for hundreds of years. However, there are few practical applications of triboluminescence. Mechano-luminescence is a form of triboluminescence, and sometimes the terms are used interchangeably. Triboluminescence has the potential to use in many fields. This paper is a review of the history and mechanics of triboluminescence, and some applications are discussed. The types of triboluminescence covered in this paper include elastic-stress mechano-luminescence, plastic-stress mechano-luminescence, and fracture mechano-luminescence. Materials and methods in developing future applications have also been included. The research reviewed in this paper gives an insight into past and current advances in the field of triboluminescence and explains the potential for future applications. [ABSTRACT FROM AUTHOR]

Graphene is one of the most emerging material in the field of nanotechnology, and it is gaining a tremendous amount of research interest in recent years. Apart from its unique electronic, electrical, mechanical, and thermal properties, graphene also possesses lower wear rate and friction coefficient. The superior tribological properties of graphene have attracted many researchers to synthesize self-lubricating nanocomposite materials that can have several applications in the automobile, aerospace, and marine industries. Graphene is also proven a competitive nanomaterial as an additive in the lubricant oil because of stable suspension and improved anti-wear properties of the component. This article aims to present the review of the advancement in the field of graphene synthesis; tribological properties of graphene; the role of graphene as reinforcement in polymer-matrix, metal-matrix, and ceramic-matrix nanocomposites; and also graphene as an additive in lubricant oil. The results reveal that addition of graphene to the composites can lead to decrease both wear rate and coefficient of friction for all three class of materials. Moreover, when graphene used as a lubricant additive, it improves the load carrying capacity of lubricant oil along with decreased friction and wear. Performance of graphene-reinforced composites and graphene suspended lubricants depend on various tribological and materials parameters which are discussed in this article. The limitation of present knowledge and future research scope are also highlighted. [ABSTRACT FROM AUTHOR]

Composites have tremendous applicability due to their excellent capabilities. The performance of composites mainly depends on the reinforcing material applied. Graphene is successful as an efficient reinforcing material due to its versatile as well as superior properties. Even at very low content, graphene can dramatically improve the properties of polymer and metal matrix composites. This article reviews the fabrication followed by mechanical and tribological properties of metal and polymer matrix composites filled with different kinds of graphene, including single-layer, multilayer, and functionalized graphene. Results reported to date in literature indicate that functionalized graphene or graphene oxide-polymer composites are promising materials offering significantly improved strength and frictional properties. A similar trend of improved properties has been observed in case of graphene-metal matrix composites. However, achieving higher graphene loading with uniform dispersion in metal matrix composites remains a challenge. Although graphene-reinforced composites face some challenges, such as understanding the graphene-matrix interaction or fabrication techniques, graphene-reinforced polymer and metal matrix composites have great potential for application in various fields due to their outstanding properties. [ABSTRACT FROM AUTHOR]