This study evaluated the mechanical properties and the chemical and thermal characteristics of low-density polyethylene (LDPE) nanocomposites reinforced with graphene oxide for manufacturing via 3D printing. LDPE nanocomposites with different graphene oxide (GO) loadings (0.5% and 1.5%) were processed by a single-screw extruder. To characterize the pre-injected material, Fourier transform infrared spectroscopy (FTIR) and thermal characterization with thermogravimetry (TGA) were used. The injected material was also characterized with mechanical impact and traction tests. The results showed that incorporating GO into the polymeric matrix added hydroxyl groups to the matrix structure, with a 39.13% increase in Young's modulus for LDPE-1.5%wtGO samples. Mechanical tests of 3D printed samples showed that, with an increase in the amount of GO in the polymer matrix, the composite loses ductility, enabling its use in 3D printing technologies and thus encouraging new studies on printed materials for various applications.

Tecnol. Metal. Mater. Min., vol.20, e2804, 2023

Since their early investigations, TiN coatings have sparked considerable interest because of their remarkable mechanical properties, especially their prominent hardness (30–60 GPa) and oxidation resistance. They are mainly used to harden and protect cutting or sliding tools and occasionally for decoration. Small quantities of different ligands, including Ni, Cu, or Co, are added to improve the smooth performance of cutting tools. These alloying elements lead to the formation of nanocomposites, potentially altering their mechanical characteristics and imparting notable flexibility. In this context, this study focuses on the production of pure TiN and Cu-doped TiN thin films. Magnetron sputtering was used as a deposition technique, simultaneously sputtering Ti and Cu-targets, both with high purity (99.99%), and in a gas mixture of Ar and N ₂ . X-ray diffraction, SEM, profilometry, nanohardness, and scratch test analyses were employed to characterize the TiN and TiN/Cu films. The results reveal that 3–4% of Cu content led to a slight decrease in hardness, while surface adhesion increased with the addition of copper. Furthermore, the elasticity of the doped films improved the strength and wear resistance of coatings with Cu compared to TiN films without added Cu.

In this work, thin films based on the Ti-Zr system were studied, deposited on a silicon substrate by the magnetron sputtering technique using simultaneously a combination of High-Power Impulse Magnetron Sputtering (HiPIMS) and Direct Current Magnetron Sputtering (DCMS) sources. The objective of this work is analyzing the effect of varying HiPIMS frequency (300 Hz, 400 Hz, 500 Hz, and 600 Hz) on the characteristics and properties of the thin films. The thickness increased between 300 Hz and 500 Hz, where the thickness measured 563 nm and 732 nm, respectively; then it decreased to 709 nm at 600 Hz. Hardness and elastic moduli also tended to decrease with increasing frequency, and the results for the first property were between 7 GPa and 10.3 Gpa, while the elastic moduli were from 114 Gpa to 157 Gpa, in which lower values were reached at higher frequencies. In the wettability test, lower contact angles were observed for samples with lower frequencies due to their high surface energy, providing better hydrophilic properties.

In the manufacture of graphene-reinforced aluminum composites, powder metallurgy has been the primary production method, proving to be highly effective. The present work addresses the production and characterization of aluminum matrix composites reinforced with graphene-based nanomaterials. The production route employed the powder metallurgy technique and was processed in two stages: first by mixing in different liquid media, and second by using distinct mixing methods. The sintered samples from the first stage were evaluated for their density, and the sintered samples from the second stage were subjected to mechanical microhardness tests. The results of the first stage indicated that among the solvents used for mixing, acetone and ethanol stood out, providing compacts with densification above 92%. In the second stage, Al/rGr composite samples produced by the mechanical mixing method using a helical impeller showed the greatest increase in hardness, achieving a 60.5% increase compared to pure aluminum.