Advanced Materials Research Vols. 718-720

Abstract: P3HT and P3HT/PCBM organic films are prepared by drop casting and spin coating and are used to fabricate solar cells on ITO. The solar cell properties are investigated by UVvisible absorption spectroscopy and X-ray diffraction (XRD). and their morphologies are discussed. The results indicate that the molecular chains of the P3HT film prepared by drop casting are perpendicular to the substrate, whereas those of the film prepared by spin coating are oriented parallel to the substrate. P3HT/PCBM films are prepared by spin coating using different PCBM/P3HT ratios.

Abstract: A highly selective chemosensor for Ag⁺ based on heterocyclic compound Diethyl 6-anilino-5H-2,3-dithia-5,7-diazacyclopenta (cd) indene-1,4-dicarboxylate (D1) was investigated. The deprotonation of N-H was observed easily in spectra of D1 (2.5×10^-5 M) in 50% H₂O/THF solution after NaOH addition, and the deprotonated D1 could interact with Ag⁺, resulted in the sharp decrease of deprotonated absorption. The addition of other metal ions would not produce an obvious change, which means quite extreme selectivity for Ag+ compared with other metal ions. The LOD of the method to detect Ag⁺ was 8.07×10^-8 M. It is indicated that a novel high selective chemosensor for Ag⁺ was build up.

Abstract: Co-based high temperature alloys have been widely used in aeronautics and astronautics industry, because of its high strength at high temperature, excellent resistance of hot corrosion and oxidation. Unlike the traditional Co-based superalloys, strengthened by solution and carbide strengthening, the novel Co-Al-W superalloys are strengthened by a ternary compound with the Ll₂ structure γ-Co₃(Al,W). And the novel Co-Al-W superalloys showing high-temperature strength greater than those of conventional nickel-base superalloys, will become the candidates for next-generation high-temperature materials. We research alloying element Ta effect on microstructure of Co-Al-W superalloys by vacuum arc melting. Compare with the microstructure before and after adding alloying element Ta of Co-Al-W superalloy, we find that most of Ta element distributed in the γ-Co substrate phase, stabilizing and reinforcement the γ phase.

Abstract: Removed at authors request due to potential serious errors

Abstract: In this work, the aluminum nitride (AlN) thin film with highly c-axis orientation was prepared successfully at water cooling condition by RF sputtering. The influence of water cooling on the crystalline quality of AlN thin film is researched. The crystalline characteristics and microstructure of AlN thin films deposited on Si (111) and Mo/Si (111) were researched by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The results indicated that highly c-axis AlN films can be synthetized at water cooling condition. The AlN film deposited on Mo thin film is titled to the surface, when that is perpendicular to the silicon substrate. Different models are proposed to explain the growth behaviors of AlN thin films on the two kinds of substrates.

Abstract: The effect of RE on modifying inclusions of 21Cr-11Ni austenitic stainless steel was studied by SEM and electron spectroscopy. Thermodynamic calculation was used to analyze the formation of RE inclusions in 21Cr-11Ni stainless steel. The result shows that sulfide and other irregular inclusions are modified to round or oval-shaped RE₂O₂S and RES.

Abstract: The anodic polarization curves of 21Cr-11Ni austenitic stainless steels with various RE contents in 3.5% NaCl neutral solutions have been measured by electrochemical methods. The effect of RE on pitting corrosion resistance of 21Cr-11Ni stainless steels has been studied by the metallographic examination. The results show that sulfide and other irregular inclusions are modified to round or oval-shaped RE₂O₂S and RES after adding RE to 21Cr-11Ni stainless steesl. RE makes sulfide, and other irregular inclusions change to dispersed round or oval-shaped RE inclusions, effectively inhibits the occurrence of pitting corrosion, thereby enhancing the corrosion resistance of 21Cr-11Ni austenitic stainless steels.

Abstract: The effects of RE on the inclusions and the mechanical properties of H13 die steel were studied. The results show that the morphologies and sizes of inclusions in H13 steel are changed, and RE played a very good role of modifying inclusions. Fracture is changed from cleavage to ductile fracture by adding RE to H13 steel. And the mechanical properties of H13 steel are improved. In comparison with H13 steel without RE, the transverse impact toughness of H13 steel with RE is increased 33.61% at 0°C, and the tensile strength and reduction of area have been improved 10.74%, 6.3%, respectively.

Abstract: The total energies of 4H-SiC with donor-acceptor-donor (D₂A) trimer codopants (D = N, P, As, and Sb, A = B, Al, Ga, and In), the formation energies of D₂A, DA, D, and A species and the binding energies were studied using ab initio calculations in order to determine the stable structures of D₂A trimer codopants in 4H-SiC. The results of the calculations indicated that some of the trimer codopants were formed and were stable in 4H-SiC. In particular, N₂Al, N₂Ga and N₂In trimer codopants with N(C_h)-Al/Ga/In (Si_k)-N(C_h) configuration and As₂B trimer codopants with As (Si_h)-B(C_k)-As (Si_h) configuration stably exist in 4H-SiC under the doping condition wherein the concentration ratio of donors to acceptors is 2 : 1.