Advanced Materials Research Vols. 284-286

Abstract: Al₂TiO₅-Si₃N₄ composites were prepared by reaction sintering process using Al₂TiO₅ and α-Si₃N₄ powders as raw materials. The effect of sintering temperature, soaking time and Si₃N₄ content on the sintering properties of the composites was studied. The results showed that the best sintering temperature and soaking time were 1550 °C and 2 h, respectively. The samples with 15 wt% of Si₃N₄ addition had good sintering properties, and its mechanical strength was 28.96 MPa, which was 2 times of the one of the samples without Si₃N₄ addition.

Abstract: Poly（phenylene-sulfide）/ Poly（ether-sulfone） polymer composites (coded as PPS/PES) reinforced by Potassium Titanate Whisker(PTW) and Polytetrafluoroethylene (PTFE) were prepared by compression molding. The effect of the filler on the mechanical and tribological properties of the PPS/PES composites was investigated, based on the evaluation of the composites’ properties and examination of the worn surfaces by means of scanning electron microscopy (SEM). Results showed that the incorporation of the PTW contributed to greatly increase the impact strength，tensile strength，and bending strength of the composites, and apparently improve its tribological performance. The composite had a best synthetical performance when the PTW content was about 20wt. %. The wear mechanism of the composites，which could be closely related to the content of PTW, gradually changed from adhesive wear to particle abrasion with the addition of PTW.

Abstract: Molten iron corrosion resistance of silicon-corundum-silicon nitride composites were investigated using corundum, silicon nitride, clay and silicon powder as the main starting materials by static crucible method. The corrosion mechanism of the composites was analyzed by means of scanning electron microscope (SEM with EDS). The results revealed that corundum-silicon nitride composites possessed good molten iron corrosion behavior and the active oxidation of silicon nitride was the main reason for loose structure of the corroded specimen; The composites produced a dense layer by addition of silicon, which made superior molten iron corrosion resistance behavior.

Abstract: This paper adopted the general method of sol-gel to prepare a list of PEG/TiO₂ phase change materials (PCMs). The chemical structure of the materials was investigated by FT-IR respectively. The infrared indicate that the materials have good chemical compatibility. The thermal properties of the samples were measured by differential scanning calorimetry(DSC) and thermogravimetry(TG). The surface topography and crystallized behavior of the materials were detected by SEM and XRD. The TG thermographs show the samples can sustain high temperature about 212°C. The DSC measurements display that the phase change temperature of the materials’ range from 52°C to 56°C. The results obtained from experiments show that the phase change materials possesses a good potential as a thermal energy storage material.

Abstract: A new O/W microemulsion system for transdermal matrine delivery was developed in order to provide clinical medication of matrine with a more convenient,reasonable and effective new form.Various factors were investigated including solubility of matrine,the skin permeability of matrine in various components, and the compatibility among surfactants, cosurfactants and oils, aiming to choose suitable surfactants, cosurfactants and oils.The pseudo-ternary phase diagrams were constructed to determine the concentration ratio of components in the microemulsion. The formulation of microemulsion was optimized by using the simplex lattice method.The optimum formulation with the highest skin permeation rate (1239.56 μg /cm²/h) consisted of 7.2% matrine,4.5% ethyl oleate- ethyl butyrate(4:1), 23 % EL-OP(1:1) ,15 % PEG-400 and water.

Abstract: The FeAl/Al₂O₃ composites were fabricated by plasma active sintering process in this research. The FeAl intermetallics compounds powders were fabricated by mechanical alloying and heat treatment process. The FeAl intermetallics compounds powders and Al₂O₃ powders were mixed and the FeAl/Al₂O₃ composite powders were prepared. The FeAl/Al₂O₃ composites bulks were fabricated by plasma active sintering process at 1200°C for 5min under the pressure of 30MPa. The phase composition and microstructure of the FeAl/Al₂O₃ composites sintered bulks were investigated. The XRD patterns results showed that the Fe-Al intermetallics compounds powders were fabricated by mechanical alloying for 60h. The FeAl intermetallics compounds powders were fabricated by heat treatment at 800°C, 900°C and 1000°C. The microstructure showed that the mean particles size of the FeAl intermetallics compounds powders produced by mechanical alloying and heat treatment process was rather fine and about 4-5μm. The XRD patterns results showed that there existed the FeAl phase and Al₂O₃ phase in the sintered composites. The FeAl/Al₂O₃ composites sintered bulks exhibited the homogenous and compact microstructure. The microstructure of the FeAl/Al₂O₃ composites became more compact and homogenous with the increase of FeAl content. The mean particles size of FeAl was about 2-3μm and the mean particles size of Al₂O₃ was about 2-3μm. The density and relative density of the FeAl/Al₂O₃ composites increased gradually with the increase of FeAl content.

Abstract: Ni₃Si compound is one of the excellent high temperature structural materials, because it possesses the attributes of high melting point, high strength, low density, excellent oxidation resistance at elevated temperatures, and magnificent corrosion resistance in acid environments, particularly sulfuric acid solutions, while the application of this compound is limited due to poor ductility at ambient temperatures and lack of fabricability at high temperatures. The incorporation of a ductile phase into the intermetallic materials has become an attractive means to modify the ductility. In this paper Ni-Ni₃Si hypoeutectic in situ composites are obtained by Bridgman directional solidification technology. Microstructure of the Ni- Ni₃Si hypoeutectic in situ composites are regular lamellar eutectic structure at the lower solidification rates, whereas eutectic cells or dendrites can be found with the increase of the solidification rate, due to the increase of the composition undercooling. Moreover, the directional solidification mechanism was investigated as well.

Abstract: Tri-n-octylamine-intercalated α-zirconium phosphate (TOA-ZrP) was prepared in the presence of (C₄H₉)₄NOH for the first time. The interlayer distance of (C₄H₉)₄NOH-intercalatedα-zirconium phosphate (B-ZrP) is 14.7 Å, larger than that ofα-ZrP (7.6 Å). The TOA-ZrP sample is highly crystallized with the interlayer distance of 22.3 Å. The molar ratio of TOA toα-ZrP in the intercalation composite was found to be 1/1.21. The composite can find application in solid extraction.

Abstract: The physicochemical properties of iron ore with arsenic in South of China was analyzed by chemical analysis, XRD, high power microscope. The effects of various factors on arsenic removal in sintering process were studied and the optimal technique parameters were obtained. The results show that the mineral of iron ore with arsenic in South of China mainly is composed of magnetite and gangue, in which arsenic with 0.282% mass content exists as FeAsS and few as As₂S₃. The oxidation and thermal decomposition reaction of FeAsS occurs in sintering process. Under feeble oxidation atmosphere the arsenic removal rate of iron ore along with reaction temperature increases, and the holding time elongates, or the coke powder content rises. The optimal removal arsenic process parameter is: reaction temperature 1050~1100°C, holding time 8~15min, and coke powder content 6%.

Abstract: The MgO-Al₂O₃-Fe₂O₃ composite was prepared at 1600°C for 3h with magnesia powder and alumina powder as raw materials and with ferric oxide powder as additive. The effect of the molar ratio of MgO/Al₂O₃ on the sintering and thermal shock resistance of the composite materials was studied. The results showed that increasing the molar ratio of MgO/Al₂O₃ could improve the densification of the Al₂O₃-Fe₂O₃ composites, with the molar ratio of MgO/Al₂O₃ increased from 3 to 5, densification of the composites didn't increased but decreased. The optimum molar ratio of MgO/Al₂O₃ of the Al₂O₃-Fe₂O₃ composite is equal to 3, the sample MA-3 exhibits better sintering densification and thermal shock resistance. Its primary crystal phases are spinel and periclase, and less amount of sosoloid 20MgO·19Al₂O₃·Fe₂O_3. So, the MgO-Al₂O₃-Fe₂O₃ composite is acceptable for application in cement rotary kiln linings and high temperature gas filter support.