Development of high performance Mg–TiO2 nanocomposites targeting for biomedical/structural applications

MWCNTs-TiO2 Incorporated-Mg Composites to Improve the Mechanical, Corrosion and Biological Characteristics for Use in Biomedical Fields

This study attempts to synthesize MgZn/TiO₂-MWCNTs composites with varying TiO₂-MWCNT concentrations using mechanical alloying and a semi-powder metallurgy process coupled with spark plasma sintering. It also aims to investigate the mechanical, corrosion, and antibacterial properties of these composites. When compared to the MgZn composite, the microhardness and compressive strength of the MgZn/TiO₂-MWCNTs composites were enhanced to 79 HV and 269 MPa, respectively. The results of cell culture and viability experiments revealed that incorporating TiO₂-MWCNTs increased osteoblast proliferation and attachment and enhanced the biocompatibility of the TiO₂-MWCNTs nanocomposite. It was observed that the corrosion resistance of the Mg-based composite was improved and the corrosion rate was reduced to about 2.1 mm/y with the addition of 10 wt% TiO₂-1 wt% MWCNTs. In vitro testing for up to 14 days revealed a reduced degradation rate following the incorporation of TiO₂-MWCNTs reinforcement into a MgZn matrix alloy. Antibacterial evaluations revealed that the composite had antibacterial activity, with an inhibition zone of 3.7 mm against Staphylococcus aureus. The MgZn/TiO₂-MWCNTs composite structure has great potential for use in orthopedic fracture fixation devices.

Microstructure, Mechanical and Ignition Characteristics of Si3N4 Reinforced Magnesium Matrix Nanocomposites

Lightweight magnesium-based materials have received attention in the automobile sector as a solution to minimize fuel consumption and greenhouse gas emissions. Magnesium has great weight-reduction potential in the aerospace sector, but its low ignition temperature limits its utilization. Improving magnesium’s ignition resistance is critical for aerospace applications. The present study developed Mg/Si3N4 nanocomposites to improve the ignition resistance to address this limitation. The nanocomposites were prepared by ultrasonically-assisted stir casting with 0.5, 1, and 1.5 vol% Si3N4 nanoparticles. The effect of Si3N4 nanoparticles on the ignition and compression characteristics was examined. SEM micrographs showed the homogeneous dispersion of Si3N4 nanoparticles with negligible clustering. Notably, the nanocomposites’ ignition resistance was increased by increasing the vol% of the Si3N4 nanoparticles. Adding 1.5 vol% Si3N4 nanoparticles resulted in the highest ignition temperature of 614 °C, 34 °C higher than pure magnesium. Similarly, the compressive properties were enhanced with the progressive addition of Si3N4 nanoparticles. The inclusion of 1.5 vol% Si3N4 nanoparticles resulted in a maximum compressive yield strength of 118 MPa and ultimate compressive strength of 323 MPa.

Chromium-free Cu@Mg/γ-Al2O3 - an active catalyst for selective hydrogenation of furfural to furfuryl alcohol

Development of a chromium (Cr)-free hydrogenation catalyst is very important to replace the existing hazardous Cr based catalyst used in the furfural hydrogenation to furfuryl alcohol. Herein, we report synthesis of well-dispersed copper nanoparticles supported on hydrothermally stable magnesium doped alumina (Cu@Mg/γ-Al₂O₃) for selective hydrogenation of furfural to furfuryl alcohol. The prepared catalyst was characterized by X-ray Photoelectron Spectroscopy (XPS), Auger Electron Spectroscopy (AES), Powder X-ray Diffraction (PXRD), Surface Area Analysis (SAA), High Resolution-Transmission Electron Microscopy (HR-TEM), Temperature Programmed Reduction/Desorption (TPR/TPD) and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) to understand textural properties of the catalyst. The prepared catalyst was found to be highly active and selective with 99% conversion of furfural and 94% selectivity for furfuryl alcohol under solvent free conditions at 443.15 K and 2 MPa of hydrogen pressure. It was also observed that the Cu@Mg/γ-Al₂O₃ catalyst is reusable (up to six runs) while maintaining its high activity and selectivity (≥94%) in the hydrogenation of furfural to furfuryl alcohol.

A catalyst for selective hydrogenation of furfural to furfural alcohol in a solvent free environment.

Recent Developments in Magnesium Metal-Matrix Composites for Biomedical Applications: A Review

Recently, there is a growing interest in developing magnesium (Mg) based degradable biomaterial. Although corrosion is a concern for Mg, other physical properties, such as low density and Young's modulus, combined with good biocompatibility, lead to significant research and development in this area. To address the issues of corrosion and low yield strength of pure Mg, several approaches have been adopted, such as, composite preparation with suitable bioactive reinforcements, alloying, or surface modifications. This review specifically focuses on recent developments in Mg-based metal matrix composites (MMCs) for biomedical applications. Much effort has gone into finding suitable bioactive, bioresorbable reinforcements and processing techniques that can improve upon existing materials. In summary, this review provides a comprehensive overview of existing Mg-based composite preparation and their mechanical and corrosion properties and biological responses and future perspectives on the development of Mg-based composite biomaterials.

Synthesis of five metal based nanocomposite via ultrasonic high temperature spray pyrolysis with excellent antioxidant and antibacterial activity

A unique five metal (Zn, Cu, Ni, Fe, and Mg) based nanocomposite material was preparedviaultrasonication high temperature spray pyrolysis maintained at 1200 °C.

Effects of Primary Processing Techniques and Significance of Hall-Petch Strengthening on the Mechanical Response of Magnesium Matrix Composites Containing TiO₂ Nanoparticulates

In the present study, Mg (1.98 and 2.5) vol % TiO₂ nanocomposites are primarily synthesized utilizing solid-phase blend-press-sinter powder metallurgy (PM) technique and liquid-phase disintegrated melt deposition technique (DMD) followed by hot extrusion. Microstructural characterization of the synthesized Mg-TiO₂ nanocomposites indicated significant grain refinement with DMD synthesized Mg nanocomposites exhibiting as high as ~47% for 2.5 vol % TiO₂ NPs addition. X-ray diffraction studies indicated that texture randomization of pure Mg depends not only on the critical amount of TiO₂ NPs added to the Mg matrix but also on the adopted synthesis methodology. Irrespective of the processing technique, theoretically predicted tensile yield strength of Mg-TiO₂ nanocomposites was found to be primarily governed by Hall-Petch mechanism. Among the synthesized Mg materials, solid-phase synthesized Mg 1.98 vol % TiO₂ nanocomposite exhibited a maximum tensile fracture strain of ~14.5%. Further, the liquid-phase synthesized Mg-TiO₂ nanocomposites exhibited higher tensile and compression properties than those primarily processed by solid-phase synthesis. The tensile-compression asymmetry values of the synthesized Mg-TiO₂ nanocomposite was found to be lower than that of pure Mg with solid-phase synthesized Mg 1.98 vol % TiO₂ nanocomposite exhibiting as low as 1.06.