Applied Mechanics and Materials Vol. 711

Abstract: The fluorine gypsum was used as research object in this paper. In order to recognize the basic properties of fluorine gypsum fully, the physical and chemical properties were analyzed through different testing means. The chemical modification (additive A, sodium sulfate, quick lime) on the activity of fluorine gypsum excitation effect were studied. The best way to compound modification was determined and the mechanism of the admixture was analyzed. On this basis, the fluorine gypsum base self-leveling mortar materials was prepared and its performances were tested. Research shows that, the optimal ratio of: additive A content 2.0% (mixed), sodium sulfate content 0.8%, quick lime content 1.5%, the fluorine gypsum self-leveling material initial setting time is 2.4h, the final setting time is 5.3h, 24h flexural strength of 2.60MPa, compressive strength of 6.05MPa, the dry flexural strength of 7.68MPa, compressive strength of 22.89MPa, the performance indicators have reached the JC/T1023-2007《Gypsum based self-leveling mortar》 requirements.

Abstract: The development of multi-scale modeling methods reveals to be of undeniable practical importance, especially to describe and predict the mechanical properties of structural materials. The present work aims to relate the atomic scale with the macro-scale performances. To this purpose a model of a crystalline structure based on the Atomic Finite Element Method (AFEM) is developed. The interatomic bonding forces of Van der Waals, the Coulomb electrostatic force and the covalent chemical bond are taken into account. It is then applied to Portlandite (CH) as well as to graphene (triple-layer graphene sheet, TLGSs). Elastic modulus of these structures based on AFEM is determined. Then, modeling of a single crystal can be traced back to the homogenized elastic properties of polycrystals. Elastic constants and elastic modulus by AFEM algorithm are in quite good agreement with literature experiment. These modeling method and algorithm provide some basic reference to other hexagonal structures.

Abstract: Ag/SiO_X nanocomposites were successfully fabricated by inductively coupled plasma (ICP) enhanced magnetron sputtering plasma where the hexamethyldisiloxane (HMDSO) was as the monomer for SiOx deposition and Ag nanoparticles were sputtered by Ar ions from Ag target. The main motivation of this work is to clarify the feasibility of Ag/SiO_X nanocomposite fabrication in a simultaneous process with plasma technology. Besides the influence of processing parameters on the microstructures and properties of the nanocomposite, such as ICP power, the deposition time and ratio of HMDSO and Argon, is investigated in this paper. With Fourier transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV-Visible), and atomic force micrograph (AFM) the microstructures of the Ag/SiO_X nanocomposite were characterized. It is founded that the microstructures and properties of nanocomposite depend on the discharge parameters. As an application the antibacterial behavior was tested. It indicates that the Ag/SiOx nanocomposites demonstrate an excellent antibiotic effect to colon bacillus and golden brown staphylococcus. It concludes that the Ag/SiO_X nanocomposite can be facilely prepared by this processing.

Abstract: In this paper the effect of solution treatment on the corrosion resistance of welding joint of Ni56Cr22Mo13 alloy was studied by polarization curves, mass loss method, SEM. The results indicated that the composition of alloy welded was not uniform and the corrosion resistance of welding joint of Ni56Cr22Mo13 alloy was poor. After solution treatment, the corrosion resistance was enhanced.

Abstract: Through to join in processing of titanium gypsum naphthalene series water reducing agent and sodium sulfate, study the effect of admixtures on the physical properties of titanium gypsum and mechanism analysis, and to determine the optimum content of admixtures. Research shows that when the content of naphthalene series water reducing agent was 3% water reducing effect is best, the titanium gypsum sample standard consistency water consumption is 126%,2h flexural strength was 1.06MPa, 2h compressive strength was 1.97MPa, absolutely dry flexural strength was 2.21MPa and absolutely dry compressive strength was 2.76 MPa. When the dosage of sodium sulfate is 1.5%, titanium gypsum physical performance is best,initial setting time and final setting time of 8 min and 10 min respectively,2h flexural strength was 1.35MPa, 2h compressive strength was 2.42MPa, absolutely dry flexural strength was 2.43MPa and absolutely dry compressive strength was 3.32 MPa.

Abstract: In this article, the influence of the churning technology on the average diameter of xonotlite particle and the micro-structure of xonotlite particle during the hydrothermal synthesis progress of the heat insulating material of xonotlite were researched. The influence of fiber adding process on the strength and density of calcium silicate insulation material was studied. The complexity and the macro mechanical properties of the fiber dispersed in the matrix with different fiber adding way were discussed. The microstructure of xonotlite was observed and analyzed by scanning electron microscope and the related mechanisms were studied.

Abstract: The hard silicon calcium stone slurry were synthesized by dynamic hydrothermal synthesis in this article, the influence of water solid ratio and carbon fiber on the performance of the calcium silicate thermal insulation material was studied. The results showed that when the water-solid ratio of 40, sodium dodecyl benzene sulfonate cited as a foaming agent, the sphericity of spherical particles was well, and xonotlite fiber developed well. The added carbon fiber could significantly increase the flexural and compressive strength and coefficient of thermal conductivity of the material. The microstructure of calcium silicate insulation material was observed and analyzed by scanning electron microscope.

Abstract: Polystyrene granules (EPS) for lightweight aggregate and cement for cementing material, while adding a variety of additives, were used to prepare cement-based composite thermal insulation materials by the method of vibration molding. The effects of different waterproof agent on water absorption and strength of cement-based composite thermal insulation materials were studied contrastively by adding emulsified stearic acid and emulsified composite waterproofing agent, and the related mechanisms were analyzed. Results showed that the waterproofing effect and strengthen effect of emulsified composite waterproofing agent is superior to emulsified stearic acid, when the content of emulsified stearic acid and emulsified composite waterproofing agent are 5% and 5%, respectively, the 2h, 24h water absorption of samples are 20.59%, 47.64% and 15.53%, 34.53%, the flexural and compressive strength of samples are 0.32MPa, 0.42MPa and 0.35MPa, 0.47MPa.

Abstract: Nanographites supported by silicon carbide (SiC) nanoparticles were prepared through one-step pyrolysis method using polycarbosilane (PCS) as the precursor at temperatures ranging from 1100°C~1400°C. The effects of reaction temperature on the morphology, microstructure and crystallinity of the graphite flakes on SiC particles were explored by means of SEM, TEM, RAMAN and XRD. The experimental results show that the desired products with core/shell structures can only be obtained at reaction temperatures higher than 1100°C. With the increase of reaction temperature (1250°C~1400°C), the thickness and the average size of sp² domains show an incremental trend before a decline while the density and the degree of deformation continuously improve. The possible mechanism for those changes was also discussed.

Abstract: Hydrogen peroxide was used as the foaming agent to reduce the density and thermal conductivity of composite insulation materials, and glass fibers were adopted to reinforce the performance of foamed composite insulation materials. Meanwhile, the mechanical properties of foamed composite insulation materials is studied, and the internal micro-morphology of samples were observed by SEM. The strengthening mechanism of fiber was analyzed. The results indicated that mixing foaming agent significantly decrease the density and thermal conductivity of samples, when the content of foaming agent was 4%, the minimum rate of thermal conductivity was 0.051W/(m•K). Wrapped VAE emulsion on the surface of glass fiber, glass fiber after surface modification could improve the strength of samples. The flexural and compressive strength of samples that adding glass fiber after surface modification were increased by 18.75% and 6.98% compared with samples that adding unmodified glass fiber.