Carbon Nanotubes (CNTs)-Reinforced Magnesium-Based Matrix Composites: A Comprehensive Review

Abstract

In recent years considerable attention has been attracted to magnesium because of its light weight, high specific strength, and ease of recycling. Because of the growing demand for lightweight materials in aerospace, medical and automotive industries, magnesium-based metal matrix nanocomposites (MMNCs) reinforced with ceramic nanometer-sized particles, graphene nanoplatelets (GNPs) or carbon nanotubes (CNTs) were developed. CNTs have excellent material characteristics like low density, high tensile strength, high ratio of surface-to-volume, and high thermal conductivity that makes them attractive to use as reinforcements to fabricate high-performance, and high-strength metal-matrix composites (MMCs). Reinforcing magnesium (Mg) using small amounts of CNTs can improve the mechanical and physical properties in the fabricated lightweight and high-performance nanocomposite. Nevertheless, the incorporation of CNTs into a Mg-based matrix faces some challenges, and a uniform distribution is dependent on the parameters of the fabricating process. The characteristics of a CNTs reinforced composite are related to the uniform distribution, weight percent, and length of the CNTs, as well as the interfacial bonding and alignment between CNTs reinforcement and the Mg-based matrix. In this review article, the recent findings in the fabricating methods, characterization of the composite’s properties, and application of Mg-based composites reinforced with CNTs are studied. These include the strategies of fabricating CNT-reinforced Mg-based composites, mechanical responses, and corrosion behaviors. The present review aims to investigate and conclude the most relevant studies conducted in the field of Mg/CNTs composites. Strategies to conquer complicated challenges are suggested and potential fields of Mg/CNTs composites as upcoming structural material regarding functional requirements in aerospace, medical and automotive industries are particularly presented.

Microstructure, Mechanical, and Corrosion Behavior of Al2O3 Reinforced Mg2Zn Matrix Magnesium Composites

“…No pitting corrosion occurred on the surface of the specimen (I) with dense white structures being detected on the surface (Figure 6b). During the corrosion of Mg in Hank's solution, the reactions in Equations ( 3)-( 6) occur [54][55][56]. According to Equation ( 5), the higher the formation of Mg(OH)2 corrosion product on the specimen surface, the higher the H2 gas volume evolved at the same rate.…”

“…The Mg(OH)2 film, which forms as layers on the surface after a certain period of time, is broken by the effect of the continuously evolved H2 gas. When the cracks where H2 gas is evolved are deeper and wider, the protective layer between the During the corrosion of Mg in Hank's solution, the reactions in Equations ( 3)-( 6) occur [54][55][56]. According to Equation (5), the higher the formation of Mg(OH) 2 corrosion product on the specimen surface, the higher the H 2 gas volume evolved at the same rate.…”

“…As the number of repetitions of this cycle increases, pitting corrosion occurs as seen in the SEM images in Figure 6c,d. When the temporary Mg(OH) 2 film layer formed on the specimen surface remains for a longer period without leaving the surface, it is expected to react according to Equation ( 7) [15,55]. After this reaction, the reaction in Equation ( 8) is also expected to occur, and permanent and protective apatite structures are formed on the surface [10].…”

Improved Bacteriostatic and Anticorrosion Effects of Polycaprolactone/Chitosan Coated Magnesium via Incorporation of Zinc Oxide

“…Mg density and its alloys (1.74 g/cm 3 -1.85 g/cm 3 ) are highly comparable to that of human cortical bone (1.75 g/cm 3 ). Mg is naturally found in bone tissue and is essential for human metabolism [8]. Mg 2+ ions formed during biomaterial degradation also contribute to tissue healing and growth [9,10].…”

Graphene Oxide Encapsulated Forsterite Scaffolds: Synergistic Influences on Mechanical Properties and Antibacterial Behavior 

“…Moreover, because of their excellent mechanical properties (strength of approximately 130 GPa and modulus of around 1 TPa), two-dimensional nanosheets like GO as a main element of nanomaterials, are the most favorable second-phase materials for composites and also can facilitate the load transfer from ceramics to graphene nanosheets due to large speci c surface area (approximately 2630 m 2 /g) that enables a high contact area with the matrix. These properties can improve the mechanical properties of graphene/ceramic composites [21][22][23][24][25] . Moreover, GO provides high antibacterial e ciency thanks to its membrane and oxidative stress with oxygen-containing functional groups at its edge and large surface area.…”