Advanced Materials Research Vols. 391-392

Abstract: Ferritic stainless steels have been widely used as solid oxide fuel cells (SOFCs) metallic interconnects. However, the evaporation of Cr₂O₃ might migrate to and poison the cathode, leading to degradation of the cell performance. In this work, Ni-P-Fe₂O₃ composite coating was deposited on the ferritic stainless steel by means of a cost-effective technique of electroless method. They are expected to be converted into (Ni,Fe)₃O₄ spinel with a high electrical conductivity and CTE match with stainless steel, which can hinder the evaporation of Cr₂O₃ formed on steel substrate exposed to the cathode environment of the SOFC. The effects of Fe₂O₃ contents, pH and temperature of solution on the deposition rate and Fe contents of the Ni-P- Fe2O3 composite coatings were investigated. The results indicated that the effects of Fe₂O₃ contents and pH of solution on deposition rate was not obvious and the deposition rate increased with increasing temperature. They had obvious influences on the Fe contents in the coating. The suitable deposition conditions are as below: the Fe₂O₃ content , pH and temperature was 16 g/L, 8.5 and 65 , respectively. The coatings consisted of Ni, Fe , P and O.

Abstract: In order to shorten the fussy experimental process in preparing colloidal solutions of silver nanoparticles by pulsed laser ablation in distilled water, a LmNet PF neural network model is developed to approach the complex nonlinear relationship between technology parameters and the average diameter for preparing colloidal solutions of silver nanoparticles. By using the constructed neural network model, the relationship between the technology parameters ( laser fluence, laser repetition, ablation time) and the average diameter is discussed, and the weakness that the nonlinear relationship could not be approached more accurately, effectively by using single-factor-experiment method is overcome. Predicted and test results showed that all the relative errors between the desired values and predicted outputs of the network are less than 10 %, but the predicted data of the neural network model are well acceptable when comparing them to the real test values, hence providing an effective, economical way for preparing colloidal solutions of silver nanopartilces.

Abstract: Water-soluble CdTe quantum dots(QDs) with mercaptoacetic molecules as ligands, were obtained by the reduction of CdCl2 through NaHTe under alkaline conditions. The sub-micron fluorescent spheres were synthesized by silica coated CdTe cadmium QDs, through the ammount control of tetraethyl orthosilicate (TEOS), ammonia, QDs suspension, ethanol and the ratio of them. The fluorescent property of as-prepared QDs was researched using fluorescent spectrometer, and some influencing factors in the process of preparation were discussed. Morphology and coated effect of silica composite spheres were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the fluorescence intensity was analyzed using fluorescence microscope.

Abstract: The cohesive energy of W and Mo nanoparticles is modeled by considering W and Mo nanoparticles as Wulff construction. The energetic characteristics of Wulff construction is described by accounting for bond number in a system. The model predictions are consistent with the corresponding experimental results, especially when the diameter of nanoparticle is smaller than 1nm, which implies the closed packed structure for small nanoparticles.

Abstract: A method for manufacturing composite ingot of 4045/3004/4045 aluminum alloy using direct-chill (DC) casting was introduced. The casting process, the temperature distribution near the composite interface and the macro- and microstructures were investigated. The results show that composite interface is well-bonded, planar and clean with little evidence of porosity, which belongs to a kind of metallurgical bonding. Also semi-solid layer with a certain thickness is formed under the effect of cooling plate, which can ensure the realization of casting process of composite ingot.

Abstract: Optically transparent hydrophobic inorganic-organic hybrid sols was obtained employing Tetraethylorthosilicate (TEOS), Methyltriethoxysilane (MTES), and Heptadecafluoro-1, 1, 2, 2-tetradecyl)trimethoxysilane (FAS), with nitric acid as catalyst. Hybrid coating was dip coated on glass slides. The results showed that the water contact angle of MTES modified SiO2 coating was only 105° . As the weight ratio FAS varied from 0 to 8 wt.%, the water contact angle reached as high as 116.5°. The coated glass presented transmittance of 92%, 2% higher than the non-coated ones. The increase in transmittance suggested an antireflective effect of the hybrid coating. With further SEM characterization of the surface morphology, we finally obtained the optimized optically transparent hydrophobic hybrid coating with the MTES/TEOS_as 1/1(molar ratio) and FAS as 2 wt.%.

Abstract: In this paper, disperse dyes were selected to dye the new tricot warp-knitted curtain fabric under high temperature and pressure, and fabrics of different colors could be obtained. Then the optical properties of fabrics were tested through the method of spectrophotometer, the effect of color on optical properties was analyzed. The results indicated that fabrics dyed by different dyes have different optical properties; its optical transmittance and reflectance decreases after dyeing, which make transmittance and reflection performance worse. The dark purple, deep yellow and light yellow samples have better light-admitting and anti-peep performance than other samples.

Abstract: Graphite nanoplatelets (Nano-Gs) were prepared by treating the expanded graphite with sonication in aqueous alcohol solution, and then the Nano-Gs/ PVC nanocomposites were fabricated by way of melt blending. The structure of Nano-Gs was characterized by FTIR and SEM, the conductive and mechanical properties of the Nano-Gs/ PVC nanocomposites were also studied. Results show that with a small amount of functional groups distributing on the surface, Nano-Gs have a thickness ranging 30-100nm and a diameter ranging 3-20μm, and disperse randomly in PVC resin matrix. The Nano-Gs/ PVC nanocomposites exhibit low volume resistivity of 104Ω•cm when the mass fraction of Nano-Gs goes beyond 10%, and the percolation threshold of the nanocomposites is as low as 6wt%. Furthermore, with the increase of the filled Nano-Gs, both the tensile strength and notched impact strength of the nanocomposites increase first and then decrease, and achieve the maximal value simultaneously with the addition of 1 wt% Nano-Gs, which increase by 8% and 29% respectively compared with the pristine PVC.

Abstract: Carbon nanotubes(CNTs) reinforced copper matrix composites were successfully produced by Friction Stir Processing (FSP). The effect of applying multiple FSP passes on the forming of composites was studied, the microstructure, microhardness and conductivity of the good forming composite were analyzed. The experimental results showed that CNTs uniformly distributed and good forming composite can be obtained by three FSP passes. Compared to the parent material, the grain size of the composite has significantly refined, and the microhardness of the composite has also greatly improved, but the conductivity of the composite has a small decrease.

Abstract: Former researchers have studied the properties of PLA/starch blended materials, but the influence of chitosan for them has not been studied yet. In this paper, it prepared the blended materials of PLA/starch/chitosan, and studied the compatible, mechanical and thermal properties of them. The results demonstrated that, since chitosan molecules had hydroxy and amino groups, which could form molecular force with the hydroxy groups in starch molecules and the carbonyl groups in PLA molecules respectively, the addition of it would improve the compatibility of PLA and starch. The SEM surface and section photos of blended materials could prove this compatibility, and the mechanical properties of blended materials also certified it. Specifically, with the addition of chitosan, the elongation, tensile modulus and tensile strength were all increase. For thermal properties, the addition of chitosan had no influence on it.