Advanced Materials Research Vol. 968

Abstract: s: For the problem that cracks exist when the advanced materials are attacked or shocked, and the cracks are hard to self-healing. The microcapsules are put forward to make great effects on healing the cracks to some extents. The manufacturing methods of microcapsules are reviewed, including Matrix Polymerization, In-situ Polymerization, In-situ Cross-linking, Solvent Evaporation Method. And the conclusion and problems are prospected finally.

Abstract: A new nanocomposite, semiconducting polythiophene (PT) confined in mesoporous silica (SBA-15) was synthesized. PT was formed in the pores of SBA-15 by subsequent oxidative polymerization with FeCl₃. Different techniques were used to characterize the nanocomposite formation. X-ray diffraction (XRD) and N₂ adsorption/desorption analysis showed that the nanocomposite possesses mesoporous structure, and the residual pore volume of nanocomposite was significantly lower than that of pure empty SBA-15. Scan electron micrographs confirmed the presence of polythiophene inside pore channels of the host, and thermogravimetric analysis proved confinement effect in the channel system.

Abstract: The LiFePO4/C cathode materials were successfully synthesized by solid state method with glucose, sucrose, citric acid, PEG-4000, starch and adlipic acid as carbon sources. The microstructure and morphology of LiFePO4/C composites were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The results showed that the carbon source is an important affecting factor for controlling the morphology and size of LiFePO4/C composites and carbon coating layers structure. The carbon coating layers synthesized with glucose and sucrose as carbon sources possess smaller ID/IG ratio demonstrating that carbon coating layers contain higher grapheme carbon. The particles of LiFePO4/C composites synthesized with glucose, PEG-4000 and starch as carbon sources have high dispersibility, good particles size distribution and near-spherical morphology.

Abstract: In this paper, perovskite oxide SrFe_0.5Co_0.5O_3-δ has been synthesized by citric acid method. The structures and the morphology of material were analyzed by XRD and SEM respectively. Using SrFe_0.5Co_0.5O_3-δ as photocatalyst, the photocatalytic activity of the degrading Congo red solution was investigated. The effect factors, such as irradiation time, catalyst dose, initial concentration of Congo red solution, pH value on the photocatalytic activity were also explored systematically. The results indicated that the photocatalytic degradation efficiency of Congo red was up to 97.96% in 100mL 5mg/L Congo red solution containing 0.30g catalyst for irradiation time of 20 min.

Abstract: The microstructure and mechanical properties of the four spring steels with different Si content treated by Q-I-Q-T process were studied by metallographic microscope, MTS, impact testing machine and X-ray stress analyzer. The results show that the tensile strength and yield strength is first increased and then decreased with the increase of Si content, the volume fraction of retained austenite and elongation are fist decreased and then increased when the Si content is less than 2.1%, and the microstructure become finer and homogeneous. When Si content reaches 2.1%, the comprehensive properties of 60Si2CrVA spring steel is the best.

Abstract: Electrolysis of cryolite-based molten salt is an important method for Al-Zr alloy production. The dissolution of ZrO₂ in the melts effects current efficiency and energy consumption of the production process of Al-Zr alloy, so it is most importance to study the solubility of ZrO₂ in the melts. In this paper, the solubility of ZrO₂ in the cryolite-based molten salt of different composition at different temperatures was measured by isothermal saturation method. It was found that ZrO₂ content increased rapidly in the initial stage, but the increase rate was very slow after two hours, so it was thought that ZrO₂ was nearly saturation after two hour-after dissolution. The solubility of ZrO₂ in cryolite-based molten salt increased markedly when increased the temperature and addition of CaF₂. The solubility of ZrO₂ in 2.2NaF·AlF₃-Al₂O₃-CaF₂ molten salt is similar with solubility of ZrO₂ in the 2.2NaF·AlF₃-CaF₂, it is reach 5.5wt%.

Abstract: Tungsten oxide (WO₃) nanorods were fabricated and evaluated as negative electrode materials for supercapacitors. The influence of the concentration of sodium chloride and pH value of the synthesis solution were investigated. The pH value of solution and sodium chloride play important roles in the formation of uniform dispersed nanorods of WO₃. Cyclic voltammetry and chronopotentiometry results show that nanorods WO₃ film exhibit advanced pseudocapacitive performance over a negative potential range of − 0.6 V to 0.2 V vs. SCE in 1M H₂SO₄ with the high specific capacitance of 114 F g^-1, compared to that of the bulk WO₃ electrode materials.

Abstract: ITO (Indium Tin Oxides) nanopowder was prepared by ammonium-calcining method. The chemical composition, morphology and crystal structure were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Base on the nucleation and growth mechanism of the powder, the temperature of heat treatment impacting on size and morphology was discussed briefly. The results showed that the nanoITO powder of particle size 20nm-40nm with well-pleasing particle shape and dispersion can be prepared at 800°C.

Abstract: A novel kind of environmentally friendly composite materials containing upper part of rice straw segments (URSS), poly (vinyl alcohol) (PVA) and waste paper (WP) were prepared by hot-pressing at 140°C for 10 min. The tensile strength, tensile elongation and hardness of composites were measured. Results showed that the tensile strength and the strength at tensile break of the composites first increased and then decreased with increasing PVA content. Tensile strength was higher than the strength at tensile break at different PVA contents, indicating that URSS/PVA/WP composite materials had certain toughness. Otherwise, URSS/PVA/WP composite materials had higher tensile strength than URSS/PVA composites. The tensile strengths of them were respectively 9.25 MPa and 3.9 MPa when prepared at PVA content of 40%. The hardness of composites lay between 90 and 96. Negligible difference exists in every composite.

Abstract: Application of chopped glass fiber strand (CGFS) in rice straw based composite was studied and the reinforcing effect of CGFS was evaluated. Rice straw powder (RSP) was used as main material and poly (vinyl alcohol) (PVA) was selected as adhesive agent. Composites were prepared by hot-pressing method at 10 MPa pressure, 140 °C for 10 min, with the mass ratio of RSP to PVA of 4:3. Results showed that the tensile strength of the composites first increased and then decreased with increasing CGFS amount. When the mass ratio of CGFS to RSP was 7:15, the composite reached its maximum strength of 20.47 MPa. CGFS showed obvious reinforcing effect. Strength at tensile break showed similar change law and tensile strength equaled to or was slightly higher than the strength at tensile break. The tensile elongations of all composites with CGFS were higher than 20%, proving the toughening role of CGFS. The hardness of composites showed certain non-uniformity and lay between 87 and 96. Negligible difference existed in every composite.