Advanced Materials Research Vol. 662

Abstract: Cement-based lightweight insulation materials were made. Cement and fly ash are main raw materials. The self-developed composite excitation agent and foaming agent are used. The method of foaming is the physical foaming. The inflection of fiber dosage on the performance of lightweight insulation materials was researched. Its influencing mechanism was discussed. Experiments show that foaming lightweight insulation materials were made with 1.22MPa bending strength, 2.95MPa compressive strength and the 0.072W/mk coefficient of thermal conductivity when the fiber mixing content is 1.2%.

Abstract: The glazed hollow beads thermal insulation board was made of glazed hollow beads and perlite by selecting cement and fly ash as cementitious materials, and adding appropriate amount of VAE emulsion and fibers, in the compression molding process. In this paper, the influence of different dosages of perlite replacing vitrified beads, VAE emulsion and fiber on the material properties were studied. Besides, the internal morphology of the sample was observed by scanning electron microscopy, and the action mechanism of the insulation material was explored.

Abstract: Polypropylene fiber, stearic acid-polyvinyl alcohol emulsion and FGD gypsum were chosen to prepare fiber reinforced FGD gypsum composites by a certain process. The effects of polypropylene fiber and stearic acid-polyvinyl alcohol emulsion on the composites were observed, and their action mechanisms were also analyzed with physical molds of waterproofing mechanism established. QUANTA FEG 250 scanning electron microscope was used to observe the microcosmic morphology of the samples. The investigations indicated that the mechanical property of fiber reinforced FGD gypsum composites was enhanced by admixture with polypropylene fiber while the water-resistant property was improved by adding the organic emulsion which could make the strength loss induced.

Abstract: The magnetic separation system is an important part of the automatic testing equipment. There are two methods to magnetize, internal magnetic attracting and external magnetic attracting. We compare the difference of the realization methods and the magnetic field distribution of the two ways. Then we select appropriate method to magnetize.

Abstract: Using Streptomyces erythreus isolated from pharmaceutical residues as a biosorbent, the characteristics and mechanism of its absorbing Pb2+ was studied. The results showed that absorptive ability of bacterial mycelia modified by sodium hydroxide was improved greatly. The reaction mechanism of modified bacterial mycelia uptake Pb2+ was analyzed by back scattered electron microscope(BSEM) and infrared spectroscopy (IR). The results of experiments indicated that some chemical groups such as -COO-、C-H and O-H among cell walls of bacterial mycelia might play the key functions adsorbing Pb2+. It was presumed that the process of modified bacterial mycelia lead uptake might be a chemical and physical process collaboratively which occurred on the cell surface of bacterial mycelia chiefly based on exchangeable reaction.

Abstract: The construction waste was processed into recycled aggregate and was used to substitute for natural aggregate to produce concrete small hollow block with grade of MU7.5. The effect of grain composition, replacement ratios and chemical activator of recycled aggregate on compressive strength of concrete small hollow block was studied. The results shows that through optimized grain composition of recycled aggregate and mixed with appropriate chemical activator, the compressive strength of concrete small hollow block with 100% recycled aggregate can be satisfied with the requirement of MU7.5 concrete small hollow block.

Abstract: Heat treatment has a signifieant impact on the performance of the GCr15 die steel. Using scanning electron microscopy, optical microscopy, hardness tester and tensile testing machine analyses the influence of double-fined treatment on microstructure and mechanical properties of GCr15 steels. The results show that the double-fined treatment can make the carbids which haven’t insoluted fine to 320nm and the grains fine to No. 10. The dislocated martensite become more after double-fined treatment; at the same time, there are more sheet-retained austernite in lathy martensite and around sheet martensite; broken-orifice changes from definitely cleavage brittleness fracture to definitely cleavage tenacity fracture. By double-fined treatment, die steel can be given the neeessary strength and toughness, and the life can be substantially increased. The superplasticity of GCr15 die steel was improved by double-fined treatment. The optimal temperature range of the elongation is: 680~780°C. Anti-oxidants can improve the elongation of GCr15 steels.

Abstract: The ledeburite carbides segregated seriously in solidification of Cr12 tool steels and the morphology is distributed in banding with fishbone shapes resulting in low toughness. Thus the tools are usually failure with tipping, fracture and collapse in services. A new high strength and high toughness tool steel was developed to adapt for the requirement of high strength materials forming. The thermodynamic theory and equilibrium principle of carbon as well as computer aided optimizing design are used in.

Abstract: 00Cr18Ni10N stainless steel spot-welded joints were inspected by ultrasound in transmission mode under the water. By comparing and studying ultrasonic transmission wave signals of the spot welded joint of existing nugget and the false welded joint which were received by digital oscilloscope, we find that there are differences in degree of attenuation between multi transmitted wave and primary transmitted wave of two kinds of joints. The degree of attenuation of multi transmitted wave of false welded joint is obviously less than that of the joint with nugget. Therefore, false welded joint can be judged and identified through the degree of attenuation of multi transmitted wave relative to primary transmitted wave, and the dissection results verify the feasibility of this test method.

Abstract: A series of BiOCl photocatalysts with different AgCl contents have been synthesized by a simple hydrolysis method at room temperature using BiCl3 and Bi(NO3)3•5H2O as the main raw materials. The resulting products were characterized with X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and UV‐vis diffuse reflectance spectra (DRS). The photocatalytic activities of these AgCl/BiOCl composites were evaluated by the degradation of rhodamine B (RhB) under UV and visible light. The results revealed that the BiOCl/AgCl with an initial 100:1 mole ratio of Bi to Ag have the highest photocatalytic activity. RhB (20 mg/L) was decolorized by 98.81% in 15 min under sun light, in contrast to 95.89% and 11.63% in 30 min under halogen lamp and UV light, respectively. The catalysts did not show any significant loss of activity after 19 recycles for the photodegradation of RhB, suggesting the photocatalyst is essential stable. Kinetic studies showed that the RhB photocatalytic degradation followed pseudo-first order kinetics reaction and fit the Langmuir-Hinshelwood kinetic equation. The rate controlling step was absorption reaction.