Hossein Bayat, Parvaneh Sangpour, Mojgan Heydari, Leila Nikzad,
Volume 22, Issue 4 (12-2025)
Abstract
In this study, we investigated the antimicrobial, bioactivity, and in vitro cytotoxicity of a nanocomposite made of copper oxide (CuO) and aluminum oxide (Al2O3) with two different morphologies of copper oxide (Spherical-sCuO and Nanoplate-pCuO), which was made using the Spark Plasma Sintering (SPS) process on a titanium substrate as an orthopedic implant. Two different weight percents of copper oxide nanostructures of sCuO NP (10 wt%, 20 wt%) and pCuO NP (10 wt%, 20 wt%) have been used in this research. Synthesized nanocomposites were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscope (FESEM). Based on the obtained results, the XRD pattern and XPS confirmed that the nanocomposites were successfully synthesized without impurity. FESEM images showed that CuO nanoparticles and nanoplates were distributed on the alumina matrix homogeneously. The antibacterial activity of synthesized nanocomposites was investigated using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), gram-negative and gram-positive bacteria, respectively. Antibacterial activity results showed that CuO nanoparticles had high antibacterial activity, and the effect of CuO nanostuctures depended not only on their morphology and size, but also on the type of microorganisms. Furthermore nanocomposite with nanoplate copper oxide exhibited more bioactivity properties than the spherical shape. S. aureus showed greater resistance to CuO nanostructure, while E. coli was more susceptible to them (15%). In addition, toxicity tests showed that nanoplate copper oxide exhibited greater toxicity due to its high surface reactivity than spherical nanoparticles. This study provides new insights into the role of copper oxide nanoparticle morphology in the properties of nanocomposites for use as orthopedic implants.
Alireza Hajialimohammadi,
Volume 23, Issue 1 (3-2026)
Abstract
This study successfully synthesized the CoCrFeNiMn high-entropy alloy (HEA) using a two-step powder metallurgy approach: mechanical alloying (MA) followed by spark plasma sintering (SPS). The research investigated the effects of processing parameters, specifically MA duration and SPS temperature, on the alloy's microstructure, densification, and mechanical properties. X-ray diffraction (XRD) analysis after 25 hours of MA (ball-to-powder ratio of 10:1) confirmed the formation of a single-phase face-centered cubic (FCC) solid solution. Scanning electron microscopy (SEM) images revealed significant powder particle refinement, with average particle sizes decreasing from initial micrometers to sub-micrometer ranges. The alloyed powders were then consolidated via SPS at temperatures of 800°C, 900°C, and 1000°C (40 MPa, 10 min in argon). Detailed analysis of the sintered samples showed relative densities ranging from 95.78% to 96.77%, with the highest density (96.77%) achieved at 1000°C. Vickers microhardness measurements exhibited a peak hardness of 446 HV at 900°C, with a decrease to 420 HV at 1000°C, primarily due to grain growth. This research establishes the combined MA and SPS approach as effective for producing high-density, high-hardness HEAs, underscoring the critical role of processing parameters in tailoring their final properties.
