Advanced Materials Research Vol. 952

Abstract: In this paper, the NiCu alloy coatings were electroplated on the 304 stainless steel coupon. The XRD was used to identify the phase structure of the as-prepared products. The SEM and EDS were used to observe the surface morphology of the as-prepared coatings and the atomic composition of the as-prepared coatings, respectively. The influences of the current density on the as-plated NiCu coatings are systematically researched. It was found that the moderate current density is beneficial to the compactness of the coatings. The content of the copper decreased and that of the nickel increased with the increasing of the current density. When the current density is smaller than 40 mA/cm², the contents of nickel and copper vary apparently. When the current density is larger than 40 mA/cm², the contents of nickel and copper vary slightly. That means the copper is more easily deposited at low current density and the nickel is more easily deposited at high current density.

Abstract: The magnetic properties of Co-P films with different structure depended on the temperature were investigated. The Co-P films happen to the transition from the weak ferromagnetic to the strong ferromagnetic at lower temperature. At higher temperature, the Co phase transformation from HCP to FCC crystal structure results in a sudden change of the magnetization of the nanocrystalline Co-P films. For the amorphous Co-P films, the occurrence of the crystallization at 610 K leads to a magnetization transition. The first-principles calculations shows that the intense exchange coupling of Co-Co and Co-P atoms from the Co and the Co₂P phase contributes to the magnetic property.

Abstract: Iron and silicon nitride powders were mixed in a certain proportion and compacted, then Fe_pure-Si₃N₄ were prepared by heating the samples in reducing atmosphere at 1100°C, 1300°C and 1500 °C, respectively. The stability of Fe_pure-Si₃N₄ prepared at different temperatures was analyzed by XRD diffraction and theoretical thermodynamics calculation. Results show that the main components of Fe_pure-Si₃N₄ at high temperatures in reducing atmosphere are Si₃N₄ and Si₂N₂O; Iron exists in Fe_pure-Si₃N₄ at 1100°C, and iron had largely converted to Fe₃Si phase at 1300°C and 1500°C, which is in accordance with the result of thermodynamic theoretical calculation.

Abstract: The distribution of hexavalent chromium in the weathering slag was studied, as well as the influenced factors of aqueous agent leaching chromium. Results showed an optimal leaching condition: the chromium particle size is 100~200 mesh, the liquid-solid ratio is 25:1, the leaching time is 4~8h. Enhanced temperature and reduced pH value are benefit to hexavalent chromium leaching. Considering the equipment corrosion of low pH, the optimal pH value is 3~4.

Abstract: The selection of an optimal material is an important aspect of design for mechanical, electrical, thermal, chemical or other application. Many factors (attributes) need to be considered in material selection process, and thus material selection problem is a multi-attribute decision making (MADM) problem. This paper proposes a new MADM method for material selection problem. G1 method does not need to test consistency of the judgment matrix. Thus it is better than AHP. In this paper, firstly, we use the G1 method to determine the attribute weight. Then TOPSIS method is used to calculate the closeness of the candidate materials with respect positive solution. A practical material selection case is used to demonstrate the effectiveness and feasibility of the proposed method.

Abstract: The effect of compression storage on structure and surface morphology of silicone rubber in silicone rubber-stainless steel interfacial system was studied in the paper by means of ATR-FTIR, Raman spectrums, XPS spectrums and SEM. FTIR and Raman spectrums analysis indicated that no chemical change in silicone rubber was found during compression storage. XPS spectrums analysis indicated that there maybe surface chemical reaction took place during compression storage. SEM analysis indicated that the number and diameter of the open holes and microholes on the surface of samples decreased significantly with storage period, which hindered air to enter the interface when pressurized state was removed, and was beneficial for vacuum adsorption.

Abstract: The purpose of the research was to investigate effect of compatibility between AlN nanoparticles and borated bis-succinimide on tribological properties of base oil. The load-carrying capacity and anti-wear (AW) performance of base oil that contains aluminum nitride (AlN) nanoparticles or borated bis-succinimide (T152B) additive was examined; the tribological properties of the compatibility between AlN and T152B were also examined. The experimental results showed that AlN nanoparticles additive can effectively improve load-carrying capacity and anti-wear performance of base oil. AlN nanoparticles and T152B compatibility experiments showed that two additives have synergies to improve anti-wear performance of base oil. These findings indicate that AlN nanopaticles is an excellent load-carrying capacity and antiwear additive, and it can be used with T152B together in base oil.

Abstract: A novel optimization methodology for stiffened panel is proposed in this paper. The purpose of the optimization methodology is to improve the first buckling load of the panel which is obtained by finite element method. The stacking sequence of the stiffeners is taken as design variables. In order to ensure the manufacturability of design, the design guidelines of stacking sequence are taken into account. A DOE based on Halton Sequence makes the initial points of genetic algorithm spread more evenly in the design space of laminate parameters and consequently accelerates the search to convergence. The numerical example verifies the efficiency of this method.

Abstract: The influence of urinary macromolecule chondroitin sulfate A (C₄S) on Zeta potential, aggregation and sedimentation of calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) nanocrystallites with a diameter of about 50 nm were investigated using nanoparticle size Zeta potential analyzer and transmission electron microscope. C₄S could increase the absolute value of Zeta potential on surface of nanoCOM and nanoCOD crystallites by adsorbing on crystal surface, it led an increase of the electrostatic repulsion force between the crystallites, so the aggregation and sedimentation of these crystallites were inhibited, and the stability of the suspension of nanoCOM and nanoCOD was improved. In conclusion, C₄S could inhibit the formation of CaOxa stones。