NANOMATERIALS (JOURNAL OF NANOCOMPOSITE MATERIALS RESEARCH)
Year:2010 | Volume:1 | Issue:4|Papers Count:8

In this research, hydroxyapatite-titanium oxide-carbon nanotubes nanocomposite coating deposited on 316L stainless steel by electrophoretic process. In order to making a stable suspension, isopropanol used as solvent and tri-ethanol amine as dispersant. Microstructure, chemical composition and structural phase of coatings were investigated by SEM, EDS, respectively. The dissolution amount of nanocomposite coatings after putting in SBF solution were analyzed by ICP method. The results showed that the microstrutural of nanocomposite coatings were so uniform and proved no presence of microcracks and agglomerated particles in structure of coatings. The distribution of carbon nanotubes and titanium oxide nanoparticles in structure of coatings were so suitable without any lamination in nanocomposite coatings. Also, the results confirmed the titanium oxide nanoparticles and carbon nanotubes improved the biological behavior of nanocomposite coatings.

Nanocrystalline La0.8Sr0.2MnO3 (LSM) powder has been prepared by co-precipitation in ammonium oxalate. STA was used to investigation of calcinations temperature. As, the optimum calcination temperature was determined 1000 °C. XRD was used for detection of phases during calcination process. The crystallite size was 46 nm that calculated by Williamson-Hall method. This powder with appropriate conduction properties can be useful for fuel cells.

In this research, the effect of the presence of MWCNTs treated by 0.01 and 0.02 weight percentages carboxylic group were studied. The concrete nanocompsite samples were prepared by uniform distribution of nanotubes in cement/sand in water. The effects of CNTs on mechanical behavior were studied by compression and flexural strength analysis of concrete nanocomposite and their microstructures investigated by SEM analysis. In presence of CNTs, the compression and the flexural strength of concrete composites increased more than 30% and 13%, respectively. Also, CNTs lead to improvement of microstructure porosity of concrete composite and therefore more solid and more compressed concrete composite will be created. The treated CNTs in concrete composite will generate more contact surface to transferring of forces. As a result, these lead to better CNT’s surface bonding with concrete matrix to prevent it from growth of defects.

Calcium phosphate bioceramics especially hydroxyapatite (HA) are the main mineralogical part of bone and tooth that have the great biocompatibility with hard tissue. In this research, nanostructure hydroxyapatite synthesized by mechanical activation procedure with precursors concluded of calcium and phosphor. Phase development, structure, particle size and morphology of HA were investigated by X-ray diffraction pattern analysis (XRD), Fourier transform infrared spectroscopy (FTIR), zetasizer instrument, scanning electron microscopy (SEM). XRD results confirmed the formation of hydroxyapatite phase and present of major bonds of HA approved by FTIR. Presence of two particle size distribution picks in zetasizer curve presented that a part of powder was agglomerated and SEM images have shown this agglomeration. The results showed the minimum time of hydroxyapatite is 20 hours that formed the mean particle size of HA  » 157 nm and crystallite size » 27 nm. The crystallite size and crystallinity of powders decreased to 24 nm and 98% to 33.6 %, respectively.

In this research, thermal conductivity and viscosity of nanofluids were investigated. Transient hot wire method was applied to measure the thermal conductivity of nanofluids. Hamilton-Crosser and Einstein formalism also were used to estimate and predict the thermal conductivity and viscosity. Some differences were observed by comparing the experimental and theoretical results since the theoretical for formalisms had less accuracy. The morphology of nanoparticles was investigated by scanning electron microscopic (SEM). Particle size analyzer was used to investigate of particle size. Our results showed that by adding 3% weight of TiO2 nanoparticles with sizes of 21 nm and 200 nm to engine oil, thermal conductivity of engine oil increased 56.72% and 23.34%, respectively. Moreover, results showed that the viscosity of nanofluids increased 8.03% and 6.75%, respectively.

In this work, BaTiO3 nanostructures synthesized by hydrothermal method at 180 oC for 2.5 h by using Dolapix ET85 and Dolapix CT64 as surfactants. Also, the effect of H2O/Ti, Ba/Ti, KOH/Ti and KOH/Ba parameters on particle size of synthesized powders were investigated. As well, the crystalline phase was determined by X-ray diffraction (XRD) and microstruce of powders were observed by scanning election microscopy (SEM). As a matter of fact, the comparison of the Dolapix ET85 effect on particle size of powders that synthesized by hydrothermal procedure to Dolapix CT64 revealed that using of Dolapix ET85 as surfactant is better than Dolapix CE64. Also, XRD and SEM results showed that increasing of pH amount decreased the particle and grain size.

In this research, Co1+2x Fe2 (1-x) O4 (x=0, 0.25, 0.5, 0.75 and 1) nanopowders were synthesized by utilizing microemulsion method with Cyclohexan/Triton X-100/1-Butanol/Aq. Soln. system and low amount of surfactant. The prepared nanopowders were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The XRD patterns indicate that the single spinel phase is exist in the samples. In addition, it was observed that with increasing the x in Co1+2x Fe2 (1-x) O4 compound, the lattice parameter constantly was increased while the crystallite sizes were decreased until x=0.5 and then decreased. The SEM images indicate that the samples have narrow size distribution between 20-50 nm.

The aim of this work is relation of nanocompsite microstructures included alumina matrix containing 1, 3 and 5 vol% of zirconia nanoparticles with mechanical properties and wear resistance of these composites. The microstractural analysis showed the beneficial effect of the zirconia particles in the alumina matrix on grain growth and improvement of the properties: up to 8% for the microhardness, 11% for the flexural strength and 23% for the wear resistance for nanocomposites containing 5 vol% of particles when compared to inclusion-free alumina nanocompsite.