A.M.A. Mohamed

Using B4C Nanoparticles to Enhance Thermal and Mechanical Response of Aluminum

In this work, Al-B4C nanocomposites were produced by microwave sintering and followed by hot extrusion processes. The influence of ceramic reinforcement (B4C) nanoparticles on the physical, microstructural, mechanical, and thermal characteristics of the extruded Al-B4C nanocomposites was investigated. It was observed that the density decreased and porosity increased with an increase in B4C content in aluminum matrix. The porosity of the composites increased whereas density decreased with increasing B4C content. Electron microscopy analysis reveals the uniform distribution of B4C nanoparticles in the Al matrix. Mechanical characterization results revealed that hardness, elastic modulus, compression, and tensile strengths increased whereas ductility decreases with increasing B4C content. Al-1.0 vol. % B4C nanocomposite exhibited best hardness (135.56 Hv), Young’s modulus (88.63 GPa), and compression/tensile strength (524.67/194.41 MPa) among the materials investigated. Further, coefficient of thermal expansion (CTE) of composites gradually decreased with an increase in B4C content.

Improved properties of Al–Si3N4 nanocomposites fabricated through a microwave sintering and hot extrusion process

In this study, nano-sized Si3N4 (0, 0.5, 1.0 and 1.5 vol%)/Al composites were fabricated using a powder metallurgy method involving microwave sintering technique followed by hot extrusion. The influence of Si3N4 content on the structural, mechanical and thermal behaviour of Al–Si3N4 nanocomposites was systematically investigated. Electron microscopy examination reveals the uniform distribution of hard Si3N4 nanoparticles in the soft Al matrix. The compressive and tensile strengths of Al composites increased with the increase of Si3N4 content while the ductility decreased. The thermal expansion coefficient of the Al composite decreased with the progressive addition of hard Si3N4 nanoparticles. Overall, hot extruded Al–1.5 vol% Si3N4 nanocomposites exhibited the best combination of tensile, compressive, hardness, Youngs modulus and thermal properties of 191 ± 4 MPa, 412 ± 3 MPa, 16.3 ± 0.8 GPa, 94 ± 2 GPa and 19.3 μ K−1, respectively. Tensile tests performed at 200 °C revealed that the tensile strength reduced by ∼35% when compared to the strength at room temperature. The strength, however, was still higher compared to that of the pure Al at 200 °C. The major enhancement in the strength of the nanocomposites is primarily attributed to the presence of uniformly distributed nano-sized Si3N4 nanoparticles in the Al matrix.

A novel classification of prostate specific antigen (PSA) biosensors based on transducing elements

During the last few decades, there has been a tremendous rise in the number of research studies dedicated towards the development of diagnostic tools based on bio-sensing technology for the early detection of various diseases like cardiovascular diseases (CVD), many types of cancer, diabetes mellitus (DM) and many infectious diseases. Many breakthroughs have been developed in the areas of improving specificity, selectivity and repeatability of the biosensor devices. Innovations in the interdisciplinary areas like biotechnology, genetics, organic electronics and nanotechnology also had a great positive impact on the growth of bio-sensing technology. As a product of these improvements, fast and consistent sensing policies have been productively created for precise and ultrasensitive biomarker-based disease diagnostics. Prostate-specific antigen (PSA) is widely considered as an important biomarker used for diagnosing prostate cancer. There have been many publications based on various biosensors used for PSA detection, but a limited review was available for the classification of these biosensors used for the detection of PSA. This review highlights the various biosensors used for PSA detection and proposes a novel classification for PSA biosensors based on the transducer type used. We also highlight the advantages, disadvantages and limitations of each technique used for PSA biosensing which will make this article a complete reference tool for the future researches in PSA biosensing.

Fabrication and Mechanical Properties of Extruded Al-SiC Nanocomposites

This work aims to investigate the effect of SiC addition on structural, microstructural and mechanical properties of developed Al-Sic nanocomposites. Al metal matrix composites reinforced by nanosized SiC particles were fabricated using high energy ball milling and microwave sintering process followed by hot extrusion. The XRD analysis indicated that the dominant components were Al and SiC. SEM/EDX micrographs showed homogenous distribution of SiC nanoparticles in Al matrix. Mechanical characterizations revealed that the addition of nanosize SiC particulates to a simultaneous increase in microhardnes, yield strength, ultimate compressive/tensile strength and reduction in ductility of the matrix. This improvement in mechanical properties can be attributed to the homogeneous distribution of reinforcement (SiC particles) and dispersion strengthening mechanism.

Scanning Electron Microscopic Studies of Microwave Sintered Al-SiC Nanocomposites and Their Properties

Al-metal matrix composites (AMMCs) reinforced with diverse volume fraction of SiC nanoparticles were synthesized using microwave sintering process. The effects of the reinforcing SiC particles on physical, microstructure, mechanical, and electrical properties were studied. The phase, microstructural, and surface analyses of the composites were systematically conducted using X-ray diffraction (XRD), scanning electron microscope (SEM), and surface profilometer techniques, respectively. The microstructural examination revealed the homogeneous distribution of SiC particles in the Al matrix. Microhardness and compressive strength of nanocomposites were found to be increasing with the increasing volume fraction of SiC particles. Electrical conductivity of the nanocomposites decreases with increasing the SiC content.

Development of Metal Matrix Composites Using Microwave Sintering Technique

In this book chapter, aluminum (Al)-based metal matrix composites (AMMCs) with various reinforcing ceramic particles, such as SiC, Si 3 N 4 , and Al 2 O 3 , were produced by microwave sintering and subsequent hot extrusion processes. The role of various nano/ micro-sized reinforcements in altering the structural, mechanical, and thermal properties of the microwave-extruded composites was systematically studied. The X-ray diffraction (XRD) patterns indicated that the main components were Al, SiC, Si 3 N 4 , and Al 2 O 3 for the studied Al-SiC, Al-Si 3 N 4 , and Al-Al 2 O 3 composites, respectively. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) elemental mapping confirm the homogeneous distribution of reinforcing particles in the Al matrix. Mechanistic studies revealed that the Al-Si 3 N 4 metal matrix composite exhibited superior hardness, ultimate compression/tensile strength, and Young’s modulus, while having a lower coefficient of thermal expansion compared to other studied Al composites. Findings presented are expected to pave the way to design, develop, and synthesize other aluminum-based metal matrix composites for automotive and industrial applications.

Surface engineering of the PLA films for fabricating dexterous humidity sensors

This study presents the surface engineering of the thin films of a biodegradable polymer, poly lactic acid (PLA), for its application in moisture/humidity sensors. The PLA films were deposited on the comb-like pre-patterned indium tin oxide coated glass substrates. The surface morphology of the thin film was modified by using various etchants having different solubilities in PLA. The surface morphology of the thin films was studied by using atomic force microscope and surface profilometer. The modified surfaces feature of the PLA films made them attractive to use as humidity sensors. The humidity sensing characteristics of the surface modified films were investigated by measuring the resistance and capacitance over a wide range of relative humidity levels (20–90% RH). An increase in capacitance and a decrease in resistance was observed by raising the humidity level inside the testing chamber. The proposed PLA based humidity sensor showed small hysteresis, high sensitivity and fast response & recovery time.

Metal Matrix Composite Coatings of Cupronickel Embedded with Nanoplatelets for Improved Corrosion Resistant Properties

The deterioration of metals under the influence of corrosion is a costly problem faced by many industries. Therefore, particle-reinforced composite coatings are being developed in different technological fields with high demands for corrosion resistance. This work studies the effects of nanoplatelet reinforcement on the durability, corrosion resistance, and mechanical properties of copper-nickel coatings. A 90 : 10 Cu-Ni alloy was coelectrodeposited with nanoplatelets of montmorillonite (Mt) embedded into the metallic matrix from electrolytic baths containing 0.05, 0.10, and 0.15% Mt. X-ray diffraction of the coatings indicated no disruption of the crystal structure with addition of the nanoplatelets into the alloy. The mechanical properties of the coatings improved with a 17% increase in hardness and an 85% increase in shear adhesion strength with nanoplatelet incorporation. The measured polarization resistance increased from 11.77 kΩ·cm2 for pure Cu-Ni to 33.28 kΩ·cm2 for the Cu-Ni-0.15% Mt coating after soaking in a simulated seawater environment for 30 days. The incorporation of montmorillonite also stabilized the corrosion potential during the immersion study and increased resistance to corrosion.

Recent advances in electroless-plated Ni-P and its composites for erosion and corrosion applications: a review

The metallic coating of surfaces plays a vital role in the protection of most industrial applications. Coatings can be carried through various routes (e.g., mechanical and electrochemical plating techniques). Electroless nickel coatings present unparalleled properties and a unique combination of corrosion and wear resistance features. Recently, the use and development of electroless nickel-phosphorus (ENP) coatings has attracted broad attention from many industries (e.g., oil and gas) due to their superior corrosion and wear resistance properties. In the present review article, mechanisms of ENP and preparation methods are briefly outlined. The review sheds light on properties of electroless Ni-P coatings and of their nanocomposites with an emphasis on new products and on their future development.

Microwave Fast Sintering of Double Perovskite Ceramic Materials

The book chapter mainly deals with the microwave sintering of high quality crystals of La2MMnO6 (M = Ni or Co) ceramics. Double perovskite La2MMnO6 (M = Ni or Co) ceramics with average particle size of ~65 nm were manufactured using microwave sintering at 90°C for 10 min in N2 atmosphere for the first time. The morphology, structure, composition, and magnetic properties of the prepared compacts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), infrared spectroscopy (IR and FTIR), and physical properties measurement system (PPMS). The corresponding dielectric property was tested in the frequency range of 1 kHz–1 MHz and in the temperature range of 300–600 K, and the ceramics exhibited a relaxation-like dielectric behavior.