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Abstract Aluminum metal matrix composite AMMCs reinforced with ceramic particles have a wide acceptance in engineering application due to their properties, but continuing problem with these materials is the difficulty of their machining due to hardness and abrasive nature of the reinforcing ceramic particles. The present work is aimed at studying the preparing of hybrid AMMC reinforced with both SiC particles and particles of graphite that have a lubricant effect. Stir casting technique was used to prepare samples with 6wt% SiC, and a hybrid sample with 6wt% SiC and 6wt% graphite. The effect of such reinforcements was investigated. The investigation included: hardness, compressive strength, required cutting force, surface roughness, as well as microscopic analysis, SEM-EDS analysis and also XRD analysis. Cemented carbide turning tool (P10) was used in all machining experiments with wide ranges of machining conditions to measure the surface roughness, and the cutting force. The results showed that an improvement of (184.8%) in macrohardness and (85%) in compressive strength had been achieved by reinforcing with 6wt% SiC, while these properties were improved by (33%) and (23%) by reinforcing with both SiC and graphite. The results of machining experiments showed that reinforcing with SiCp alone caused the surface roughness and the main cutting force to be increased by (32-80%) and (50.5–100%) respectively in comparison with the base matrix. In hybrid composite graphite reduces the effect of SiCp on the surface finish, so as the roughness of the machined hybrid sample was increased only (22.9 - 70.4%) in comparison with that for base matrix, while the main cutting force was increased only (42 - 66%).61-71

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The structural characterization was discussed in the present paper of the pure MgO nanoparticles and the doped (Mg(1-x)pbxO) nanoparticles specimens, where (0 ≤ x ≤ 0.03). The modified Pechini method was used to prepare all the specimens. From (DTA), the convenient temperature of decomposition from Mg(OH)2 to MgO was above 375°C. The structure investigation (XRD) revealed that all the specimens have identical space groups and index well to cubic structures. The obtained crystallite size by Scherrer's equation was increased with increasing the fraction of doping except for (Mg0.97Pb0.03O) due to the formation of PbO oxide. The molecular vibration by FTIR demonstrated that all the pure and doped specimens have the same framework. As the incorporation of Pb2+ ions increases, the bands get broader, and the intensities increase in the ranging 800-400 cm-1 due to vibrations of O-Mg and O-Pb bands, respectively.

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Doping magnesium oxide nanoparticles (MgO-NPs) forms a good material formagnetisation applications. The Room Temperature Ferromagnetic (RTFM) of Pb2+-dopedions MgO-NPs synthesised by a modified Pechini method are discussed in the present paper.The structural, morphological and magnetic properties of the samples were characterised byX-ray diffraction (XRD), Field Emission scanning electron microscopy (FE-SEM), EnergyDispersive Spectroscopy (EDS) and vibrating sample magnetometer (VSM).The XRD results showed that the synthesised materials have a single set of peaks in the XRDpatterns, corresponding to the cubic phase of MgO-NPs. As the Pb content increased in thehost MgO-NPs leading to an increase in the lattice parameter, the interplanar spacing and thecrystallite size; however, the intensity decreased.Small spherical nanoparticles (22.87–29.05nm) were observed in the Pb2+-doped ions MgOsamples by (FE-SEM). The purity of the samples was confirmed using EDS spectroscopy.The pure MgO and doped samples exhibiting RTFM may be attributed to vacancy defects,which caused local magnetisation. The saturation magnetism (Ms) was found to be varied asa function of doping concentration. The maximum (Ms) was found at x=0.015 ofMg0.985Pb0.015O sample. The obtained results suggest that both Pb doping and oxygenvacancies play an important role in the development of room-temperature ferromagnetism. (15) (PDF) Structural and Magnetic Characterisations of Pb-Doped MgO Nanoparticles by a Modified Pechini Method Structural and Magnetic Characterisations of Pb-Doped MgO Nanoparticles by a Modified Pechini Method. Available from: https://www.researchgate.net/publication/346789537_Structural_and_Magnetic_Characterisations_of_Pb-Doped_MgO_Nanoparticles_by_a_Modified_Pechini_Method_Structural_and_Magnetic_Characterisations_of_Pb-Doped_MgO_Nanoparticles_by_a_Modified_Pechini_Metho#fullTextFileContent [accessed Jul 03 2023].

ملخص البحث :

Doping magnesium oxide nanoparticles (MgO-NPs) forms a good material formagnetisation applications. The Room Temperature Ferromagnetic (RTFM) of Pb2+-dopedions MgO-NPs synthesised by a modified Pechini method are discussed in the present paper.The structural, morphological and magnetic properties of the samples were characterised byX-ray diffraction (XRD), Field Emission scanning electron microscopy (FE-SEM), EnergyDispersive Spectroscopy (EDS) and vibrating sample magnetometer (VSM).The XRD results showed that the synthesised materials have a single set of peaks in the XRDpatterns, corresponding to the cubic phase of MgO-NPs. As the Pb content increased in thehost MgO-NPs leading to an increase in the lattice parameter, the interplanar spacing and thecrystallite size; however, the intensity decreased.Small spherical nanoparticles (22.87–29.05nm) were observed in the Pb2+-doped ions MgOsamples by (FE-SEM). The purity of the samples was confirmed using EDS spectroscopy.The pure MgO and doped samples exhibiting RTFM may be attributed to vacancy defects,which caused local magnetisation. The saturation magnetism (Ms) was found to be varied asa function of doping concentration. The maximum (Ms) was found at x=0.015 ofMg0.985Pb0.015O sample. The obtained results suggest that both Pb doping and oxygenvacancies play an important role in the development of room-temperature ferromagnetism (PDF) Structural and Magnetic Characterisations of Pb-Doped MgO Nanoparticles by a Modified Pechini Method Structural and Magnetic Characterisations of Pb-Doped MgO Nanoparticles by a Modified Pechini Method. Available from: https://www.researchgate.net/publication/346789537_Structural_and_Magnetic_Characterisations_of_Pb-Doped_MgO_Nanoparticles_by_a_Modified_Pechini_Method_Structural_and_Magnetic_Characterisations_of_Pb-Doped_MgO_Nanoparticles_by_a_Modified_Pechini_Metho#fullTextFileContent [accessed Dec 30 2023].

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The structural characterization was discussed in the present paper of the pureMgO nanoparticles and the doped (Mg(1-x)pbxO) nanoparticles specimens,where (0 ≤ x ≤ 0.03). The modified Pechini method was used to prepare all thespecimens. From (DTA), the convenient temperature of decomposition fromMg(OH)2 to MgO was above 375°C. The structure investigation (XRD) revealedthat all the specimens have identical space groups and index well to cubicstructures. The obtained crystallite size by Scherrer's equation was increased withincreasing the fraction of doping except for (Mg0.97Pb0.03O) due to theformation of PbO oxide. The molecular vibration by FTIR demonstrated that allthe pure and doped specimens have the same framework. As the incorporation ofPb2+ ions increases, the bands get broader, and the intensities increase in theranging 800-400 cm-1 due to vibrations of O-Mg and O-Pb bands, respectively (PDF) Engineering and Technology Journal Structural Characterization of (Mg (1-x) pb x O)-NPs by Modified Pechini Method A R T I C L E I N F O_