Author
Mehdi Shahedi Asl
Other affiliations: University of New Brunswick, Islamic Azad University, University of Tabriz
Bio: Mehdi Shahedi Asl is an academic researcher from University of Mohaghegh Ardabili. The author has contributed to research in topics: Spark plasma sintering & Sintering. The author has an hindex of 63, co-authored 197 publications receiving 8437 citations. Previous affiliations of Mehdi Shahedi Asl include University of New Brunswick & Islamic Azad University.
Papers
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TL;DR: In this article, the authors present the recent achievements on carbon additives incorporated in ZrB2 ceramics, improved properties, and their advancements, and explore the advantages, disadvantages, and the productivity of the introduced composite materials.
168 citations
TL;DR: In this article, a near fully dense mullite-TiB2-CNTs hybrid composite was prepared successfully trough spark plasma sintering, which showed uniform distribution of TiB2 reinforcements in mullite matrix without any pores and porosities.
153 citations
TL;DR: The present document aims to provide a brief collection of the latest outcomes about several electrode materials of flexible supercapacitors based on TMOs and present this review by categories.
150 citations
11 Feb 2015-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the influence of graphene reinforcement on the sintering process, microstructure, and mechanical properties (Vickers hardness and fracture toughness) of ZrB2-SiC composite is discussed.
Abstract: In this paper, the hot pressing of monolithic ZrB2 ceramic (Z), ZrB2–25 vol% SiC composite (ZS), as well as 5 wt% graphene reinforced ZrB2–25 vol% SiC composite (ZSG) is investigated. The hot pressing at 1850 1C for 60 min under a uniaxial pressure of 20 MPa resulted in a near fully-dense ZSG composite (499% relative density). In addition, the influence of graphene reinforcement on the sintering process, microstructure, and mechanical properties (Vickers hardness and fracture toughness) of ZrB2–SiC composite is discussed. It was disclosed that the grain growth of the ZrB2 matrix was effectively stopped by SiC particles and graphene nano-platelets. The fracture toughness of ZSG composite (6.4 MPa m 1/2 ) was strongly enhanced by incorporating the mentioned reinforcements into the ZrB2 matrix, which is higher than that of Z ceramic (1.8 MPa m 1/2 ) and ZS composite (4.3 MPa m 1/2 ). After the hot pressing process, the fractographical outcomes revealed that some graphene nano-platelets were kept in the composite microstructure, apart from SiC grains, which lead to the toughening of the composite through graphene nano-platelets wrapping and pull out, crack deflection, and crack bridging. & 2014 Elsevier B.V. All rights reserved.
142 citations
TL;DR: In this paper, the authors reviewed the CoFe2O4 nanoparticles doped with various elements and their applications in various fields, including permanent magnets, magnetic recorders in high-density and micro-wave devices, and magnetic fluids.
140 citations
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TL;DR: The use of graphene as reinforcement for structural materials is motivated by their exceptional mechanical/functional properties and their unique physical/chemical characteristics as discussed by the authors. But this review focuses on MMCs and CMCs because of their technological importance for structural applications and the unique challenges associated with developing high-temperature composites with nanoparticle reinforcements.
Abstract: This review critically examines the current state of graphene reinforced metal (GNP-MMC) and ceramic matrix composites (GNP-CMC) The use of graphene as reinforcement for structural materials is motivated by their exceptional mechanical/functional properties and their unique physical/chemical characteristics This review focuses on MMCs and CMCs because of their technological importance for structural applications and the unique challenges associated with developing high-temperature composites with nanoparticle reinforcements The review discusses processing techniques, effects of graphene on the mechanical behaviour of GNP-MMCs and GNP-CMCs, including early studies on the tribological performance of graphene-reinforced composites, where graphene has shown signs of serving as a protective and lubricious phase Additionally, the unique functional properties endowed by graphene to GNP-MMCs and GNP-CMCs, such as enhanced thermal/electrical conductivity, improved oxidation resistance, and excellent bi
456 citations
TL;DR: In this paper , the state-of-the-art S-scheme heterojunction has demonstrated its superiority in photocatalysis and provided new insights into its general designing criteria.
Abstract: Photocatalysis is a green technology to use ubiquitous and intermittent sunlight. The emerging S-scheme heterojunction has demonstrated its superiority in photocatalysis. This article covers the state-of-the-art progress and provides new insights into its general designing criteria. It starts with the challenges confronted by single photocatalyst from the perspective of energy dissipation by borrowing the common behaviors in the dye molecule. Subsequently, other problems faced by single photocatalyst are summarized. Then a viable solution for these problems is the construction of heterojunctions. To overcome the problems and mistakes of type-II and Z-scheme heterojunctions, S-scheme heterojunction is proposed and the underlying reaction mechanism is summarized. Afterward, the design principles for S-scheme heterojunction are proposed and four types of S-scheme heterojunctions are suggested. Following this, direct characterization techniques for testifying the charge transfer in S-scheme heterojunction are presented. Finally, different photocatalytic applications of S-scheme heterojunctions are summarized. Specifically, this work endeavors to clarify the critical understanding on curved Fermi level in S-scheme heterojunction interface, which can help strengthen and advance the fundamental theories of photocatalysis. Moreover, the current challenges and prospects of the S-scheme heterojunction photocatalyst are critically discussed.
425 citations
Journal Article•
TL;DR: In this article, the authors determined that nitrogen vacancies (NVs) could endow graphitic carbon nitride (g-C₃N₄) with the photocatalytic N₂ fixation ability.
Abstract: Photoreduction of N₂ is among the most interesting and challenging methods for N₂ fixation under mild conditions. In this study, we determined that nitrogen vacancies (NVs) could endow graphitic carbon nitride (g-C₃N₄) with the photocatalytic N₂ fixation ability. Photocatalytic N₂ fixation induced by NVs is free from the interference of other gases. The reason is that NVs could selectively adsorb and activate N₂ because NVs have the same shape and size as the nitrogen atom in N₂. In addition to this, NVs could also improve many other properties of g-C₃N₄ to support photocatalytic N₂ fixation. These new findings could elucidate the design of efficient photocatalysts for photocatalytic N₂ fixation.
279 citations
TL;DR: Spark plasma sintering (SPS) as discussed by the authors is a widely used powder metallurgy technique for high-dimensional materials, where the sample is simultaneously subjected to uniaxial pressure and electrical current in a vacuum or protective atmosphere.
248 citations
TL;DR: In this paper, the authors reviewed the recent advances in oxidation and ablation resistance of carbon/carbon composites and highlighted some open problems and future challenges in the development and application of these materials.
Abstract: Carbon/carbon (C/C) composites are considered as one of the most promising materials in structural applications owing to their excellent mechanical properties at high temperature. However, C/C composites are susceptible to high-temperature oxidation. Matrix modification and coating technology with ultra-high temperature ceramics (UHTCs) have proved to be highly effective to improve the oxidation and ablation resistance of C/C composites. In this paper, recent advances in oxidation and ablation resistance of C/C composites were firstly reviewed, with attention to oxidation and ablation properties of C/C composites coated or modified with UHTCs. Then, several new methods in improving oxidation and ablation resistance were discussed, such as by using nanostructures to toughen UHTCs coatings or carbon matrix and the combination of matrix modification and coating technology. In addition, relevant ablation tests with scaled models were also briefly introduced. Finally, some open problems and future challenges were highlighted in the development and application of these materials.
244 citations