Advanced Materials Research Vols. 393-395

Abstract: A novel direct electroless nickel plating method was developed for the AZ91D magnesium alloy. The electroless nickel initial deposition morphology was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The initial deposition characteristics of the coating and the deposition mechanism of the nickel layer are discussed. The results show that after activation, an uneven scaly-activated membrane was formed on the AZ91D magnesium alloy surface. The weakest part of the activated membrane dissolved first, where small Ni particles deposited initially. These deposited Ni particles had high catalytic activity and they were involved in the catalytic reduction reaction of hypophosphite, from which P was precipitated. As the plating proceeded, the number of the deposited Ni particles gradually increased in a three-dimensional manner and the surface was gradually covered by the growing cellular particles. A compact pore-free nickel-plated film was finally formed.

Abstract: In this paper, the detection of sub-nanometer wood flour based on neural network control, how to improved the quality of wood flour is proposed. In the analysis of the advantages of neural network controller, as the auxiliary controller for the PID controller, and improving the control effect of the system. With the contrast of the experimental results, illustrates the quality of the sub-nanometer wood flour has been improved by the neural network control.

Abstract: Through the test of citric acid of cement paste, setting time and compression strength changes, and combined with XRD, SEM, discusses the influence of citric acid on cement hydration process. The results show that: citric acid can effectively increase the initial cement fluidity, when the content is exceed to 0.1%, the 60 min flow loss of increased gradually. Citric acid retarding effect increases with dosage, but there is a critical dosage, when the dosage is less than 0.1%, the initial setting time and final setting time increased slowly; When the dosage more than 0.1%, the initial setting time increased slowly, but the final setting time increases rapidly; With the increase in citric acid dosage, AFt diffraction peaks increases, while the CH peak decreases, indicating that the citric acid accelerated the initial hydration of C3A, while inhibiting C3S hydration and promoting AFt generation

Abstract: Nb microalloying added phosphorus high strength IF steel was used to study the effect of coiling temperature and cold reduction ratio on the microstructures and mechanical properties. The experimental results showed that the recrystallization had finished. Under coiling temperature 650°C and cold reduction ratio 75%, and under coiling temperature 600°C or 700°C and cold reduction ratio 65%, the yield strength, tensile strength were lower , the elongation was higher. The plastic strain ratio r value and the strain hardening exponent n value were reached the higher value, respectively, the r value was approximate 1.8, and the n value was approximate 0.26. Therefore, the suggested the optimal coiling temperature is 700°C, cold reduction ratio is 65% to 75%, and it is optimal process of Nb microalloying added phosphorus high strength.

Abstract: The effect of electromagnetic field on the solidification structure of Cu-3.2%Ni-0.8%Si alloy had been investigated in this paper. The results show that applying electromagnetic field during the solidification of Cu-3.2%Ni-0.8%Si alloy can refine as-cast structure and δ-Ni2Si phase. The morphology of δ-Ni2Si phase changes from coarse massive shape to fine dotlike shape. The above-mentioned effects become more obvious with the increasing in current intensity.

Abstract: Research was done on carbon fiber surface treatment techniques on boundary-bonding state and properties of short carbon fiber reinforced phenol formaldehyde (PF) resin/graphite composite. By gas-phase oxidative surface treatment (GPOST)、gas-phase and liquid-phase oxidative surface treatment (GLPOST), carbon fiber and PF resin /graphite matrix is on weak boundary bonding state. The exerted outside stress can not be effectively transmitted, the composite strength is lower than that of PF resin/graphite matrix; By thick nitric acid liquid-phase oxidative surface treatment (TNALPOST) which the nitric acid has high density, fiber and matrix is on relatively weak boundary bonding state, the exerted outside stress can be effectively transmitted and composite strength can be raised on some degree. With carbon fiber content by TNALPOST 3.wt%~ 4.wt% and PF resin content 15.wt%, the composite can meet both the mechanical strength and electrical conductivity requirement on carbon filler/polymer bipolar plate by USA Department of Energy.

Abstract: High-energy shot-peening on H13 steel after quenched. The samples with or without high-energy shot-peening were ion-nitrided at 520°C for 3h．The Microstructure，nitriding depth, hardness gradient, surface phase and Corrosion resistance of the nitride layers were compared between the high-energy shot-peening samples and the original samples using optical microscope, micro-hardness tester, X-ray diffraction and CH1660A electrochemical test. Results show that the high-energy shot-peening greatly speeds up the nitriding on the H13 steel at 520°C for 3h.. The depth of ion-nitriding layer after shot peening is from 0.11mm to 0.16mm, micro-hardness of the surface layer is from 998HV0.5 to 1105HV0.5, The hardness gradient is slightly flat . Phase structure and content of the surface is different by Powerful shot-peening and not. Corrosion resistance of the samples by high-energy shot-peening is significantly improved because it is easier to form a stable passive film.

Abstract: In this paper, (Na0.5Bi0.5)TiO3 -based solid solutions were studied to improve piezoelectric properties as those found in the PbZrO3-PbTiO3 (PZT)-based ceramics. The 0.98(Na0.5Bi0.5)TiO3 -0.02Ba(Sn0.08Ti0.92)O3 (0.98NBT-0.02BST) ceramics with the addition of 0~2.0 wt.% Nb2O5 have been prepared following the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Sn0.08Ti0.92)O3 diffuse into the lattice of (Na0.5Bi0.5)TiO3 to form a solid solution, in which a hexagonal phase with a perovskite structure was found. For 0.98NBT-0.02BST ceramics with the addition of 0.5 wt.% Nb2O5, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.12 and 0.28, respectively, at the sintering of 1100oC for 3 h. The ratio of thickness coupling coefficient to planar coupling coefficient is 2.3. It is obvious that 0.98NBT-0.02BST ceramics by adding low quantities of Nb2O5 are one of the promising lead-free ceramics for high frequency electromechanical transducer applications.

Abstract: In this article, wood-plastic composites(WPCs) were manufactured with wood flour(80～120mesh、40～80mesh、20～40mesh、10～20mesh) combing with high density polyethylene(HDPE). Effects of the size of wood flour on mechanical properies and density of composites were investigated. Results showed that particle size of wood flour had an important effect on properitiesof WPCs. Change of mesh number had a outstanding effect on flexural modulus, tensile modulus and impact strength, howere, little effect on flexural strength and tensile strength. When mesh number of wood flour changed from 80～120mesh to 10～20mesh,flexural modulus and tensile modulus were respectively enhanced by 42.4% and 28.4%, respectively, and impact strength was decreased by 35.5%.Size of wood flour basically had no effect on density of composite within 10～120mesh. The use of wood flour or fiber as fillers and reinforcements in thermoplastics has been gaining acceptance in commodity plastics applications in the past few years. WPCs are currently experiencing a dramatic increase in use. Most of them are used to produce window/door profiles,decking,railing,ang siding. Wood thermoplastic composites are manufactured by dispering wood fiber or wood flour(WF) into molten plastics to form composite materials by processing techniques such as extrusion,themoforming, and compression or injection molding[1]. WPCs have such advantages[2]：(1)With wood as filler can improve heat resistance and strength of plastic, and wood has a low cost, comparing with inorganic filler, wood has a low density. Wood as strengthen material has a great potential in improving tensile strength and flexural modulus[3]；(2) For composite of same volume, composites with wood as filler have a little abrasion for equipment and can be regenerated；(3)They have a low water absorption and low hygroscopic property, They are not in need of protective waterproof paint, at the same time, composite can be dyed and painted for them own needs；(4)They are superior to wood in resistantnce to crack、leaf mold and termite aspects, composites are the same biodegradation as wood；(5)They can be processed or connected like wood；（6）They can be processed into a lots of complicated shape product by means of extrusion or molding and so on, meanwhile, they have high-efficiency raw material conversion and itself recycle utilization[4]. While there are many sucesses to report in WPCs, there are still some issues that need to be addressed before this technology will reach its full potential. This technology involves two different types of materials: one hygroscopic(biomass) and one hydrophobic(plastic), so there are issues of phase separation and compatibilization[5]. In this paper, Effects of the size of wood powder on mechanical properties of WPCs were studied.

Abstract: Based on the density functional method, the electronic structures and the optical properties for pure and La or In doped SnO2 are comparatively investigated in detail. The calculation results indicate that both the doping of La and the doping of In induce effective reduction of the band gap of SnO2, the impurity elements form new highly localized impurity energy level at the top of the valence band near the Fermi level. The interaction between electrons changed after doping which leads to the change of electrical properties .Meanwhile, red shifts are revealed in both the imaginary part of dielectric function and the absorption spectra corresponding to the change of band gaps