The aim of this article focuses on identifying how the addition of iron micro- and nanoparticles influences the physical properties of magnetorheological composite materials developed with a polydimethylsiloxane (PDMS) matrix with different contents of silicone oil used as additive. A number of characterization techniques have been performed in order to fully characterize the samples, such as cyclic and uniaxial extension, rheology, swelling, Vibrating sample magnetometer (VSM), X-ray Diffraction (XRD), Scanning electron microscopy (SEM), Fourier-Transform Infrared (FTIR), X-ray photoelectronic spectroscopy (XPS) and Thermogravimetric analysis (TGA). The comparison between two matrices with different shore hardnesses and their mechanical and chemical properties are elucidated by swelling and tensile tests. In fact, swelling tests showed that higher crosslink density leads to increasing elongation at break and tensile strength values for the composite materials. The best mechanical performance in the magnetorheological material was observed for those samples manufactured using a higher silicone oil content in a hard polymeric matrix. Furthermore, it has been found that the magnetic properties are enhanced when nanoparticles are used as fillers instead of microparticles.

This paper focuses on reporting results obtained by the spark plasma sintering (SPS) consolidation and characterization of aluminum-based nanocomposites reinforced with concentrations of 0.5 wt%, 1 wt% and 2 wt% of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Experimental characterization performed by SEM shows uniform carbon nanotube (CNT) dispersion as well as carbon clusters located in the grain boundary of the Al matrix. The structural analysis and crystallite size calculation were performed by X-ray diffraction tests, detecting the characteristic CNT diffraction peak only for the composites reinforced with MWCNTs. Furthermore, a considerable increment in the crystallite size value for those Al samples reinforced and sintered with 1 wt% of CNTs was observed. Hardness tests show an improvement in the composite surface hardness of about 11% and 18% for those samples reinforced with 2 wt% of SWNCTs and MWCNTs, respectively. Conductivity measurements show that the Al samples reinforced with 2 wt% of MWCNTs and with 0.5 wt% SWCNTs reach the highest IACS values of 50% and 34%, respectively.