Abstract: Aluminium titanate-alumina (AT-A) composites were sintered from the precursor powders prepared by two different methods: a simple sol-gel based heterogeneous precipitation method and a traditional blending method. The crystalline phase, microstructure, mechanical strength, sintering properties, and thermal expansion coefficient (TEC) of the sintered AT-A composites were investigated and compared. The heterogeneous precipitation method increases the homogeneity of the precursor powders and improves the mechanical and sintering properties of the AT-A composites. The AT-A composites with a Al:Ti ratio of 2.2 achieve the optimal performance where the bending strength is high and the TEC remains low.
Abstract: 2 system at 700°C. The results showed that so long as Cu appears or the electrodeposit process carries on, Cu++ can be reduced into Cu+; that the electrochemical reaction process of copper is a quasi-reversible process mix-controlled by ion copper diffusion rate and electron transport rate; that the electrochemical reaction mechanism is Cu++e-→Cu; that the electrocrystallization process of copper is an instantaneous hemispheroid three-dimensional nucleation process; that the Cu ion diffusion coefficient is 2.5×10-4cm2∙s-1 at experimental conditions.
Abstract: Corrosion behavior and mechanism of E-glass fiber in simulated oilfield environment including CO2, H2S and Cl- were firstly studied. After simulated corrosion test, morphology of E-glass fiber was gathered using SEM. Chemical bonding status and elemental analysis were systematically investigated by XPS, FT-IR and EDS. The results revealed that corrosion of E-glass fiber in simulated oilfield acidic medium was primarily attributed to ion exchange mechanism, which was not only controlled by acid concentration, but also dominated by formation of complex ions or insoluble salts. The depletion of cations on E-glass fiber surface can disrupt the continuity of glass network, therefore reducing the strength of fiber.
Abstract: Removed due to plagiarism. The original paper is published by: 2009 The Authors. Journal compilation, 2009 Society of Dyers and Colourists, Color. Technol., 125, 8–13, doi: 10.1111/j.1478-4408.2008.00169.x
Abstract: The piezoelectric coefficients of 1-3 piezoelectric tubular composites are studied. Taking into account the non-uniform electric field distribution in piezoelectric tube, the piezoelectric coefficients as functions of volume fraction, aspect ratio, tube density and matrix materials were discussed. By means of finite element software, the relationship between piezoelectric coefficients and ceramic volume fraction was derived to validate theoretical results. This research provides theoretical guidance and basis for the design of 1-3 piezoelectric tubular composites.
Abstract: new flux method is explored to decrease the reactive temperature of in situ chemical reaction to fabricate particles reinforced aluminum matrix composites. When B2O3 flux is added into the mixed reactive salts the melting points of them decrease with the increase of adding amount of B2O3 in the range of 1-5wt.%. When w(B2O3)=5% the melting point of K2TiF6-B2O3 salt is 450°C,which is decreased by 90°C compared with that of pure K2TiF6. Meanwhile the in situ reactive time is shortened and the actual volume fraction is increased.
Abstract: The melting temperatures of CaO-(2CaO•SiO2)-B2O3-SiO2-(Al2O3) slag system were investigated. The results indicate that B2O3 has significant fluxing effect on this slag system. When the content of B2O3 is about 10% in these slag system, the mass ratios of w(CaO)/w(SiO2) and (CaO)/w(Al2O3) can be controlled in the scope of 1.5-8.0, the melting temperature of slag is still lower than 1340°C, which is suitable for steelmaking and secondary refining process. As a conclusion, when 10% B2O3 is employed as fluxing agent, a kind of CaO-based slag system with ultra-high basicity, ultra-low alumina content as well as low melting temperature can be obtained.
Abstract: According to the coexistence theory of melted slag structure, a calculation model of mass action concentrations for CaO-Al2O3-SiO2 slag system has been established, by which the mass action concentrations of all structure units in CaO-SiO2-Al2O3 systems are calculated. The effects of Al2O3 content and slag basicity on the mass action concentrations are investigated. The results indicate that both basicity and the content of Al2O3 have remarkable effects on mass action concentrations of CaO, 2CaO•SiO2, CaO•SiO2, CaO•Al2O3 and 2CaO•SiO2•Al2O3, etc. Furthermore, the effects of Al2O3 content on mass action concentrations are relevant with slag basicity. The basicity has more influences on mass action concentrations of CaO, CaO•SiO2, 2CaO•SiO2 and 3CaO•SiO2, whereas the basicity has little effect on mass action concentrations of other structure units in CaO-SiO2-Al2O3 system.
Abstract: Different dosages of BN-B4C compound additive have been introduced for preparing specimen with fused quartz granule (d50=10μm). Fused quartz ceramic materials were fabricated in reduction atmosphere at various temperatures for 1h. The characterizations were carried out by thermal expansion ratio, apparent porosity, cold modulus of rupture (CMOR) and SEM as well as by X-ray diffraction (XRD). The effect of BN-B4C on the sintering, crystallization and properties of fused quartz was investigated. The result reveals that with increase of the temperature, the apparent porosity and CMOR of specimens decrease. The specimen C sintered at 1300°C possessed a maximum CMOR (22.31 MPa). The specimen C sintered at 1350°C has more compact microstructure. The lowest thermal expansion ratio of the specimens sintered at various temperatures was obtained when the dosages of compound additive is 3%. With increasing BN-B4C content, the role on inhibiting crystallization was improved. The specimens containing 3 wt% BN-B4C had obvious effect on inhibiting crystallization of the specimens sintered at various temperatures.