Advanced Materials Research Vols. 79-82

Abstract: The modification of light calcium carbonate powder was studied by wet surface modification in n-Butanol and water solution. The modification process was analyzed by modifying temperature, rotation speed, aluminate coupling agent dosage and n-Butanol percentage. The characters of modified calcium carbonate were investigated by the contact angles with water/glycerol/liquid paraffin/DOP and infrared spectroscopy (IR). The contact angles/water of modified CaCO3 powder obtained in optimum conditions was 134.5°. The results indicated that the surface property of CaCO3 powder changed from the hydrophilicity to the lipophilicity.

Abstract: The oily sludge-based adsorbents for flue gas desulfurization were prepared by pyrolysis. Based on benzene adsorptivity, the conditions of pyrolysis process were optimized. The optimum prepared conditions of adsorbent material were in nitrogen atmosphere and 550°C, 4h, 10°C/min for the pyrolysis temperature, pyrolysis time and heating rate, respectively. In this case, the maximum benzene adsorbability was 60.12mg/g. Moreover, the main influencing factor was pyrolysis temperature, secondly was pyrolysis time and finally was heating rate. The sludge-based adsorbents were appropriate for flue gas desulfurization. The sulfur capacity of adsorbents via a flue gas desulfurization test after subsequent processing was about 3% and breakthrough time could keep to 109 min.

Abstract: Now there is a motivation for creation of the materials possessing a considerable difference of physical and chemical properties in volume of composite materials 1 . Composite materials allow realizing a complex of various properties which cannot be realized simultaneously in mono material. The perspective in reception of a new smart nanomaterial is basically defined by possibilities which create processing conditions Choosing and manufacturing of fibers refers to the second stage of composite material reinforcement. Process of assemblage of a composite material from the details made at first two stages of process refers to the third stage. But at each stage of process of manufacturing of a composite material there are specific problems. The basic problem at composite material creation, as a rule, is essential contradictions between engineering solutions for various stages of process.

Abstract: Nanostructured coatings based on interpenetrated polymer network of polyurethanes, polyacrylates or epoxide resins and containing nanoparticles of SiO2, TiO2 and other metal oxides introduced into a polymeric matrix was elaborated. Technology of the unique coatings provides control of their micro-and nano-structures. Formulation of a new class of nanocomposite materials is characterized by the absence of contaminants in the polymers technology [1]. The main components of the technology are branched (dendro)-aminosilanes which serve as curing agents for many oligomers. Additional hydrolysis of aminosilane oligomers creates the secondary nano-structured network polymer that improves performance of the compound.

Abstract: Prepared silicon carbide(SiC) ceramic foams combined with mullite whiskers which synthesized by in-situ reaction. Studied on the influence of temperature on the synthesis of mullite whisker, and the influence of mullite content on the compressive strength, thermal shock resistance of SiC ceramic foams. The results indicate that the performance of mullite whiskers synthesized at 1400°Cwere best, when mullite content was 25%, SiC ceramic foams could reach the maximum compressive strength for 1.75MP, the most thermal shock resistance for14 times.

Abstract: The Al-Mg coatings were deposited on high-speed electro-galvanizing steel by using double-target DC magnetron sputtering. Numerous Al-Mg coatings were prepared with a range of different Mg-target power at different substrate temperatures. The morphologies and compositions were analyzed by SEM, EDS and XRD, the corrosion-resistance properties with different sputtering parameters were discussed by electrochemical measurement. It was found that with the substrate temperature increasing, the porosity decreased, meanwhile, higher substrate temperature resulted in more granular particles and an increased average particle size, but that did not affect corrosion properties obviously. The corrosion-resistance properties were found to be significantly affected by the targets power. As the power of Al-target and Mg-target were 900W and 200W respectively, the film acted the best corrosion-resistance property. Corrosion current density was approximately 4μA/cm2, decreased significantly compared with galvanized sheet. After analysis, the coating was mainly composed of Al12Mg17 which afforded sacrificial anode protection. As the Mg-target power over high relative to Al-target, the coating was composed of Al12Mg17 and MgZn2, the latter can cause micro-galvanic acceleration of corrosion.

Abstract: Ti3Al inter-metallic compounds were successfully prepared via high energy ball milling and the subsequently heat treatment. Near full dense (TiB2, TiCx)/B4C matrix composites were fabricated by the addition of Ti3Al. The maximum values of hardness, flexural strength and fracture toughness are HRA 94.1, 580.34MPa and 8.07MPa•m1/2 respectively for 20wt% Ti3Al content. Furthermore, the microstructures of the composites were analyzed by XRD, SEM and energy spectrum methods.

Abstract: Composite materials have some obvious advantages such as high specific strength 、high specific modulus 、corrosion resistant 、abrasion resistant and so on, it is believed to be highly competitive compare to other materials. Advanced composite materials have been used more and more widely in defense industry, among them carbon fiber reinforced resin base composite material is most representative [1] ,there has great value for the study of carbon fiber composite materials. Eddy current is a nondestructive testing technology widely used on metal materials, the using of eddy current technology in aviation domain has a long history, but there is few reports on composite material with eddy current NDT. Experiments show that eddy current used on composite material is feasible, and the result is satisfactory. The thickness measurements of carbon fiber advanced composite materials have been done in two different ways.

Abstract: In this study, macroporous, pH sensitive polyacrylic acid hydrogels were prepared by using different concentration of aqueous NaCl solutions as the polymerization medium. The optical photos showed that the pore morphologies of the hydrogels were dependent on the concentration of NaCl. Swelling studies showed an increase in equilibrium swelling ratio as the NaCl concentration in the polymerization medium increased from 0 to 0.7mol/L. The hydrogels exhibited stronger sensitivity to pH changes, and showed much faster reswelling and deswelling response rates with the NaCl concentration increasing in the polymerization medium.

Abstract: The effect of small addition of niobium on the mechanical properties of grain boundary allotriomorphic ferrite (FGBA)/ granular bainite (BG) air cooling bainitic steel has been investigated by tensile test, Optical Microscopy (OM), and scanning electron microscopy (SEM) observation. The results show that (1) The small addition of niobium improves the mechanical properties of the FGBA/BG steel obviously. Compared with Non-Nb FGBA/ BG steel, 0.02% Nb increases the tensile strength and yield strength about 20% (From 780Mpa to 937Mpa)and 17%(From 557Mpa to 650Mpa) respectively, remaining 18% elongation. (2) With the addition of 0.02%Nb, both the size and the volume fraction of FGBA decrease. Meanwhile, the volume fraction of refined intragranular ferrite and M-A islands increases. Compared with Non-Nb steel, the volume fraction of M-A island in 0.02Nb steel increases from 21% to 31%, and the average size of M-A island decreases from 1.2μm to 0.95um.(3)It is indicated that the small addition of Nb(0.02%) not only refines the allotriomorphic ferrite grain but also promotes the nucleation of intragranular ferrite, both of which in turn contribute to the refinement of granular bainite cluster including its ferrite platelets and M-A islands. (4)It is suggested that the strengthening effect of 0.02%Nb can be mainly attributed to the segregation of Nb to γ/α phase boundaries(solute drag-like effect) rather than the precipitation strengthening of Nb(C,N). Nb enrichment in the α/γ interphase causes the decrease of C-activities and activity gradient in the austenite matrix around the α/γ interphase and thus causes the decrease of C-diffusion rate in austenite, and further the restraint to ferrite growth. The effects also depress bainite transformation temperature and driving force, as a result, the bainite cluster is refined.