Microwave Assisted Synthesis and Powder Flowability Characteristics of Rare-Earth Aluminate (ReAlO3, Re = La, Gd, Nd, Y) Powders
TL;DR: In this paper, rare earth aluminates (ReAlO3) produced via microwave assisted synthesis have good powder flowability and is an ideal material for thermal spray coating process.
Abstract: Rare-earth aluminate (ReAlO3, Re = La, Gd, Nd, Y) powders were successfully synthesized from a mixture of Re2O3 (Re = La, Gd, Nd, Y) and Al2O3 powders using microwave assisted synthesis which consists of two steps: microwave heat treatment and high-energy milling process. X-ray diffraction, laser particle size analyzer, nitrogen adsorption technique (BET) and scanning electron microscopy were employed to study the phase composition, particle size and distribution, specific surface area and powder morphology. The results suggest that microwave assisted method led to a very rapid synthesis of ReAlO3 compared to conventional solid-state reaction process. The crystals produced by microwave assisted synthesis have a perovskite structure and the particle size distribution ranges from 3.6-51.5 µm. The present work demonstrates that rare-earth aluminates (ReAlO3) produced via microwave assisted synthesis have good powder flowability and is an ideal material for thermal spray coating process.
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TL;DR: A comprehensive review of microwave-assisted synthesis of various materials for photoluminescence and photocatalytic applications can be found in this article , focusing on the reaction parameters employed and the structural and morphological properties obtained.
Abstract: This review provides a comprehensive discussion on the microwave-assisted synthesis of various materials for photoluminescence and photocatalytic applications. In the past decade, because of its ability to synthesize nanomaterials through faster, cleaner and more cost-effective routes compared to conventional heating, microwave techniques have gained significant importance for the synthesis of metal oxides, fluorides, sulphides, and quantum dots. Additionally, due to the uniqueness of its heating mechanism, the synthesis of materials in various nanostructured forms through microwave-assisted methods has been of great interest and is widely pursued. The materials thus synthesized have been applied as sensing elements in gas sensors, luminescent nanoprobes in bioimaging, materials in fuel cells and solar cells and as photocatalysts for water treatment and energy harvesting. This review describes and discusses their optical and photocatalytic performance in detail, emphasizing on the reaction parameters employed and the structural and morphological properties obtained.
13 citations
TL;DR: In this paper, the authors focus on some of the most commonly applied methods used in traditional and advanced shear cell testing techniques to measure the flow of powders and explore micro properties like the angle of repose, internal friction, bulk density, flow function, yield loci, powder rheometry under precisely controlled conditions of consolidation stress.
Abstract: Preformulation studies like storage, transfer, fluidisation, and compaction, are subject to the excellent
flowability of the powder It is often required for proper operational management and consistent design
of industrial processes Two basics methods have been utilised to characterise the flow behaviour of bulk
solids Traditionally, powder has been evaluated in terms of simple and straight forward techniques like
Hausner’s ratio, Carr’s index, bulk density, and angle of repose Despite that, the results obtained in the
traditional method lack predictability, reproducibility, sensitivity, and the actual association between the
resulting data and flow behaviour Henceforth the results varied for weight variation, content uniformity,
and dissolution, etc during the preparation of final dosage forms To overcome these limitations of the
traditional methods, the advanced techniques are being utilised to explore micro properties like the angle
of internal friction, bulk density, flow function, yield loci, powder rheometry under precisely controlled
conditions of consolidation stress Ultimately these techniques help to design, choose suitable excipients,
reduce time along with cost, and improve the health of society This review focuses on some of the most
commonly applied methods used in traditional and advanced shear cell testing techniques to measure the
flow of powders
12 citations
Cites background from "Microwave Assisted Synthesis and Po..."
...Such a fine parameter measurement produces a very repeatable and sharp description of the powder behaviour which is used in the following advanced shear testers[45-47]....
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TL;DR: In this article , the authors provide an overview of the structure, properties, and classification of perovskites based on lanthanum and aluminum (LaAlO3) and discuss the challenges, advantages, and limitations associated with the preparation methods and catalytic applications.
Abstract: Lanthanum aluminate-based perovskite (LaAlO3) has excellent stability at high temperatures, low toxicity, and high chemical resistance and also offers wide versatility to the substitution of La3+ and Al3+, thus, allowing it to be applied as a catalyst, nano-adsorbent, sensor, and microwave dielectric resonator, amongst other equally important uses. As such, LaAlO3 perovskites have gained importance in recent years. This review considers the extensive literature of the past 10 years on the synthesis and catalytic applications of perovskites based on lanthanum and aluminum (LaAlO3). The aim is, first, to provide an overview of the structure, properties, and classification of perovskites. Secondly, the most recent advances in synthetic methods, such as solid-state methods, solution-mediated methods (co-precipitation, sol–gel, and Pechini synthesis), thermal treatments (combustion, microwave, and freeze drying), and hydrothermal and solvothermal methods, are also discussed. The most recent energetic catalytic applications (the dry and steam reforming of methane; steam reforming of toluene, glycerol, and ethanol; and oxidative coupling of methane, amongst others) using these functional materials are also addressed. Finally, the synthetic challenges, advantages, and limitations associated with the preparation methods and catalytic applications are discussed.
7 citations
TL;DR: In this article, a photocatalytic degradation of methylene blue (MB) was used as a probe reaction to evaluate their photocatalysis activity under visible-light irradiation.
Abstract: In recent years, fabricating the visible-light induced photocatalysts based on the concept of plasmonic photocatalysis provides an efficient way to reduce environmental pollution. Accordingly, the present investigation has been carried out to develop such materials based on lanthanum aluminate (LaAlO3; LAO) and Ag/AgBr. The Ag/AgBr/LAO composite is prepared by deposition of metallic Ag nanoparticles onto the pre-prepared AgBr/LAO heterostructure by visible-light photo-reduction. The characteristic properties of synthesized catalysts were investigated by using a variety of techniques such as XRD, N2 adsorption–desorption, FESEM/EDX/EDS mapping, TEM-HRTEM, UV–Vis DRS, FT-IR, XPS, and PL measurements. The photocatalytic degradation of methylene blue (MB) was used as a probe reaction to evaluate their photocatalytic activity under visible-light irradiation. Because of the higher surface area with vast mesoporous nature, enhanced visible light absorption, and more efficient charge separation after the deposition of Ag/AgBr, the composite Ag/AgBr/LAO showed enhanced photocatalytic activity compared with pristine LAO. The recycling experiment revealed excellent stability (up to five successive cycles) of Ag/AgBr/LAO composite. Furthermore, a photocatalytic mechanism is proposed for the degradation of MB over Ag/AgBr/LAO composite. The composite Ag/AgBr/LAO can be used as a promising catalyst for environmental remediation.
7 citations
01 Jan 2021
TL;DR: In this paper, a detailed explanation of microwave heating and its application in the processing of various composites of engineering importance is provided. And a separate section is dedicated to the preparation of ceramics and nano-materials using microwave technology.
Abstract: Quick, efficient and cost-effective processing methods grab attention in the current manufacturing scenario. At the same time, they are expected to be cleaner and environment-friendly. Microwave processing and fabrication of engineering materials seem to be a promising technique meeting both these demands. This chapter provides a detailed explanation of Microwave heating and its application in the processing of various composites of engineering importance. Further, it also highlights the suitability of Microwaves in joining and surface treatments of materials. In the end, a separate section is dedicated to the preparation of ceramics and nano-materials using Microwaves. The chapter culminates with a discussion on future perspectives and applications of this technology in processing and fabrication of other engineering materials.
7 citations
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TL;DR: In this article, the phase diagram of the Al2O3-Y2O 3 system has been investigated with five different compositions by XRD and in situ high temperature neutron diffractometry.
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114 citations
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TL;DR: In this article, the flowability of spherical glass beads having mean particle size (dp) ranging 20-170μm were studied and their aerated and tapped bulk densities, angle of slide ( σ s ), and angle of repose ( β ) were measured.
57 citations
TL;DR: In this paper, the use of microwave energy for application in several material processing technologies apart from food processing is discussed, and a special emphasis has been made in the processing of glass adopting microwave energy.
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55 citations
TL;DR: In this article, a combustion synthesis of perovskite LaAlO3 powder was performed using a concentrated solution of nitrates of lanthanum and aluminate as oxidiser and glycine acid as fuel, with the aim of obtaining nanosized crystallites of this material with high specific area at relatively low temperature.
53 citations