Advanced Materials Research Vol. 741

Abstract: The phase field method was applied to study the effect of second-phase particles (SPP) with different geometric orientations and shapes on grain growth. The results show that, in the grain growth process, most of the spherical second-phase particles located at triple junctions, while the stick SPPs located at the grain boundaries along the grain boundary. The second-phase particles are of the strong pinning effect on grain boundary and the limiting grain radius can be expressed by Zener relations. In the condition of the second-phase particles area fraction and size remaining the same, the stick SPPs are of more effective pinning on grain growth than that for spherical SPPs, and the orientation of disk second-phase particles is also an influence factor for pinning effect. Stick second-phase particles with multiple orientations can make a better pining effect than those with only one orientation.

Abstract: Wood plastic composite (WPC) in this study was made from high density polyethylene (DHPE) or low density polyethylene (LDPE) with different species wood flour using extrusion. Ethylene vinyl acetate (EVA) was used to improve the weathering resistance performance of WPC. Degradation test and ageing test were employed to study the weathering stability of WPC modified by EVA. The results show that EVA can improve the ageing resistant performance of WPC and have no significant effect on the degradation resistant performance of WPC. It suggests that EVA can be used to improve the weathering resistance performance of WPC.

Abstract: Ba_0.6Sr_0.4TiO₃ (BST) thin films were fabricated by solgel technique on Pt/Ti/SiO₂/Si substrate without and with PbO seeding layer from precursor solutions with different concentrations. The crystal structure, surface morphology, dielectric properties and leakage current density of BST thin films are investigated as functions of the concentration of PbO precursor solution. Its found that the growth orientation of BST thin films with PbO seeding layer can be modulated through adjusting the concentration of PbO precursor solution. BST thin film with PbO seeding layer from 0.05 M precursor solution shows the highest dielectric constant and tunability, which may be attributed to the high crystallization and amplitude of the polarization in high (100) preferred orientated films. The leakage current density of BST films increases with the increasing concentration of PbO precursor solution and agrees well with the space-charge-limited current mechanism at room temperature.

Abstract: In this paper, based on the constitutive equations of piezoelectric effect and piezomagnetic effect, a 1-3 model of laminate magnetoelectricity composite materials is established. By combining material mechanical kinematic equations and circuit state equations, magnetical-mechanical-electrical equivalent circuit of laminate magnetoelectric composite materials is raised and magneto-electricity switch effect is analyzed. Upon these, a new kind of laminate magnetoelectricity composite material, Terfenol-D/PMNT/Terfenol-D, is put forward. Taking 1-3 model as an example, with the help of MATLAB, we simulate and calculate the magnetoelectric response of this new material. Through calculation, a conclusion is drawn that this new materials magnetoelectricity switch coefficient is higher than that of Terfenol-D/PZT/Terfenol-D. This theoretical basis will put this new material in a good position in magnetoelectric materials preparation.

Abstract: Polycarbonate/Poly (lactic acid) blends were prepared through melt blending at the present of different kinds of organotin catalyzers such as monobutyltin oxide (MBTO), di-n-butyltinoxide (DBTO), di-n-octyltin oxide (DOTO), and dibutyltin dilaurate (DBTL). The effect of kind and mass of catalyzers on the properties of blends were investigated. The results showed that the DBTO is the most effective catalyzer on catalyzing the transesterification between PLA and PC, which corresponds to the analysis of morphologies and mechanical properties of blends. The use of DBTO could improve the compatibility and thus strengthen the mechanical properties of blends signficantly , and the optimal mass is 0.8wt% of blends.

Abstract: Aliphatic polycarbonate Polycarbonate/poly (lactic acid)/(PPC/PLA) blends were prepared by melt blending, 1,2-propanediol isobutyl POSS (P-POSS) were added into the blends as a compatilizer and reinforcer. The morphologies, mechanical properties and rheological properties of blends were investigated systematically. The results showed that the adding of P-POSS could improve the compatibilization of PPC and PLA obviously. The thermal stability of the blends was enhanced but the crystallization was effected slightly. Moreover, the tensile strength and impact strength of blends exhibited a considerably increase.

Abstract: In this study, the process of magnetic abrasive polishing (MAP), installed permanent magnet to improved magnetic force on surface of wafer, was used for planarization of sapphire wafer. The surface roughness and polished area were investigated according to polishing time. The results showed that the improving strategy of magnetic force was helpful to improvethe roughness of sapphire and the polished area was gradually increased according to polishing time since the frictional heat between magnetic abrasives and wafer surface caused the improvement of fluidity for magnetic abrasive. In addition to, for using medium based on oil, the better improvement of surface roughness was achieved comparing to silicone gel medium of high viscosity.

Abstract: Magnetic abrasive polishing is one of the most promising finishing methods applicable to complex surfaces. Nevertheless this process has a low efficiency when applied to very hardened materials. For this reason, EP-MAP hybrid process was developed. EP-MAP process is expected to machine complex and hardened materials.In this study, deburring process using EP-MAP hybrid process was proposed. EP-MAP hybrid deburring process is applied to micro channel, and thereby it can obtain both deburring process and polishing process. To evaluate the performance criteria of the EP-MAP hybrid deburring process, EP-MAP hybrid deburring process on the micro channel was performed. Through investigating the effect of working parameters, namely magnetic flux density, electric potential, working gap and feed rate, error of height and surface roughness according to working parameter is analyzed using design of experiment method.

Abstract: In order to broaden the utilization of desulfurization gypsum in China and achieve the direct usage of desulfurization gypsum, in this paper, citric acid (CA), sodium citrate (SCA), sodium tripolyphosphate (STPP), Sodium hexametaphosphate (SP) were selected as retarder to modify desulfurization gypsum. The experiment results are as follows: the effect of SP, STPP, CA, SCA on desulfurization gypsum initial setting time is obvious; the turn is STPP> CA> SCA> SP; when the retarder dosage of STPP in desulfurization gypsum reaches 0.5%, the initial setting time can be extended to 210 min, the final setting time to 240min, which fully meets the demand of gypsum-site construction; inhibiting gypsum particles dissolution and preventing the growth of crystal nucleus are the fundamental reasons of STPP.