Novel sulfonic acid-functionalized chitin nanowhiskers (sChW) with enhanced proton conductivity were prepared for fabricating green and environmentally friendly chitosan (CS)-based nanocomposite polymer electrolyte membranes (PEMs). The performance of sChW in the development of direct methanol fuel cell (DMFC) nanocomposite membranes was also assessed. The manufactured nanocomposite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), CHNS elemental analysis, X-ray diffractometry (XRD), ion-exchange capacity (IEC), water uptake, as well as proton conductivity and methanol permeability. The results showed that modification of chitin nanowhiskers (ChW) with sulfonic acid groups, as the proton-conducting sites, could enhance proton conductivity of the manufactured membranes, leading to a fall in methanol permeability, as a result of attractive interactions between the negatively charged sulfonic acid groups on the surface of sChW and the positively charged amine groups in the chitosan chains. Thus, the selectivity parameter (the ratio of the proton conductivity to methanol permeability) of the chitosan-based nanocomposite membranes significantly increased from 3900 for pristine chitosan PEM to 26, 888 S. s. cm−, 3 (ca. 6. 8 times) for a membrane with 5% (wt) sChW. The functionalization strategy used herein can pave the way for the development of efficient polyelectrolyte membranes for applications in direct methanol fuel cells.

C-SiC composites with carbon-based mesocarbon micro beads (MCMB) preforms are new type of high performance and high-temperature structural materials for aerospace applications. In this study MCMB-SiC composites with high density (2.41 g.cm-3) and high bending strength (210 MPa,) was prepared by cold isostatic press of mixed mesophase carbon powder derived from mesophase pitch with different amount (0, 2.5, 5%) nano SiC particles. All samples were carbonized under graphite bed until 1000 oC and finally liquid silicon infiltration (LSI).Microstructure observations resultant samples were performed by scanning electron microscopy and transition electron microscopy (SEM & TEM). Density, porosity and bending strength of final samples were also measured and calculated. Results indicates that the density of samples with nano additive increased significantly in compare to the free nano additives samples.

Al2O3-SiC-C castables are one of the advanced refractories which are favored in many applications because of the high corrosion resistance, thermal shock resistance, thermal conductivity and mechanical strength. They are mainly used in troughs and slag/metal runners of blast furnaces. In Iran for lining of runners, ramming mixes which are the oldest refractories used for such application are still in use. In this study a typical Al2O3-SiC-C castable was selected and the influence of amount of silicon carbide on properties was investigated. Bulk density, apparent porosity, permanent linear change, cold crushing strength and cold modulus of rupture of samples was determined at 110, 1000, 1250 and 1500°C. Phase analysis was carried out on all specimens fired at different temperatures.Mean while crucible and finger corrosion techniques were performed to determine corrosion resistance of the samples. Micro structural investigations were also done on all fired and corroded specimens. The results showed that increasing SiC content caused a slight increase in water demand, as well as decrease in mechanical strength and caused porosity increase. However, bulk density was not affected significantly Corrosion resistance was also decreased.

With the development of the applications of magnesium components in many industries, relatively low corrosion and wear resistance of this alloy leads to the development of different protective layers. In this paper, the effect of SiC reinforcement on the cold spraying behavior of Al-SiC powder on a magnesium alloy substrate is addressed. The pure Al powder is blended with different amount of SiC powder including 25, 50 and 75 wt. %. The feedstock is sprayed on sand blasted AZ31B substrate. The process is carried out with 30bar pressure and 300° C temperature of process gas (Nitrogen). A 20mm standoff distance is used for spraying. The effect of different values of SiC on the deposition behavior of the Al-SiC powders are investigated. The coatings cross-section is evaluated by scanning electron microscopy, image analysis software and microhardness test. The results showed that the high velocity reinforcement particles leads to the SiC particle breaking during the process. This phenomenon increases the porosity of the coating. Furthermore, the higher value of reinforcement in initial powder leads to the homogenous distribution of them and the higher coating hardness. The hardness of the Al-75wt% SiC coating is about 90 HV, which is increased by 80% compared to pure Al coating microhardness.

In this research, Electrochemical deposition of Ni-SiC-Gr nano composites was studied. The watts bath was used for electrodeposition. The SiC and graphiteparticles were suspended in the electrolyte and stirred. The effects of SiC nanoparticles Content in bath on the composite coating were investigated. The X-Ray diffraction (XRD) an scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) metods were used to characterize the micro structure of deposited layer. The results showed that the microhardness the increases with increases in pif value. The coating that pericipitated at 25 gr/lit were maximum hardness. The results demonstrate the morphological properties and hadness of Ni-SiC-Gr nano composite coatings fabricated via electrodeposition were improved with increase SiC nanoparticles in the bath. also demonstrated the hardness of coatings were not related to the graphitparticles content in the composite coating.

In this study, Al2O3–SiC Nano composites have been fabricated by mixing of alumina powder containing 0.05% weight magnesium oxide and silicon carbide nano powders, followed by hot pressing at 16500C. The mechanical properties of Al2O3-SiC Nano composites containing different volume fraction of nano scale SiC particles were investigated and compared with those of alumina.The fracture mode and microstructure of specimens were investigated by means of scanning electron microscopy. The Nano composites were tougher compared to alumina when they were hot pressed at the same temperature. The young’s modulus is decreased by increasing the volume percent of SiC. The values hardness and fracture toughness of the Nano composites is increased by increasing the volume percent of SiC up to 7.5% and then decreased slightly. The ballistic energy dissipation ability is decreased by increasing the volume percent of SiC up to 5% and then increased slightly. The Scanning electron microscopy observations showed that fracture mode is changed from intergranular for alumina to transgranular for Nano composites. It also proves that growth of grain is decreased by increasing the volume fraction of SiC particles.

Composite and nanocomposite Ni-Co/SiC coatings were synthesized by electro-codeposition of micro and nano-sized SiC particles with average diameter of 10 mm and 20nm using horizontal electrodes. Surface morphology, chemical composition, phase composition, hardness and corrosion resistance of the deposited coatingswere studied using SEM observations and EDX, XRD, microhardness and polarization measurements as a function of the electrodeposition current density. The results indicated that the nanocomposite coatings exhibit higher hardness and corrosion resistance compared with the composite coatings containing micro-sized SiC particles despite their lower percentage of the SiC content. The maximum hardness values of 615HV and 490HV were obtained for nanocomposite and composite coatings deposited at current density of 3A/dm2. The observed properties were discussed based on the structural details.