Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract： The corrosion of three Fe-xCr-5Al alloys containing 10%, 15% and 20%Cr(atomic fraction) is investigated beneath KCl-ZnCl2 deposits in air at 600 ℃. Compared to their oxidation in air without salt films, all the alloys suffer from accelerated oxidation in the presence of salt deposits due to the dissolution of chromia in the chlorides. The corrosion resistance of the alloys could not be effectively improved by the additions of high Cr content. The accelerated corrosion of Fe-xCr-5Al alloys induced by ZnCl2-KCl salts is attributed to the dissolution of the protective chromia in the melt, leading to the formation of loose and non-adherent scales on the surface of these alloys. The effect of Cr in Fe-Cr-Al alloys is clarified, and the accelerated degradation mechanism is also discussed in terms of the relevant thermodynamical phase stability diagrams.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract： To improve the properties of dye-sensitized solar cells (DSSC), three-dimensional ordered TiO2 hollow spheres (3DOHS-TiO2) films were synthesized using polystyrene spheres (290-300 nm) colloidal crystals as sacrificial templates. The photoelectric conversion performances of the DSSC based on double- layered films P25- TiO2/3DOHS- TiO2 were investigated. SEM results show that the orderly arranged TiO2 hollow spheres form hexangular and square arrays, and the hollow spheres connect to their neighbors through pores. The center-center spacing of the 3DOHS-TiO2 is 260-270 nm, and the thickness of the hollow shells is 40-50 nm. TEM results show that the shell is composed of a lot of tiny particles resulting in a mesoporous framework. The mean size of the anatase TiO2 nanoparticles of the shells is ca.10 nm as estimated from the HRTEM image. By compared with the P25-TiO2 nanocrystalline DSSC (η =4.32%), the DSSC based on the double-layered films P25-TiO2/3DOHS-TiO2 exhibit a higher photoelectric performance (η =6.98%). The enhancement of the cell performance can be attributed to the en-hancement of light harvesting of the light scattering ability of the layer 3DOHS-TiO2.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract： Core/shell structured composite abrasives with solid-silica (SSiO2) cores and mesoporoussilica (MSiO2) shells were synthesized using tetraethylorthosilicate as silica source, ammonia solution as catalyst and cetyltrimethylammonium bromide as sacrificial template. The prepared abrasives were characterized by small angle XRD, FESEM, HRTEM, FTIR, TGA, nitrogen adsorption- desorption isotherm and the corresponding pore size distribution. The results show that the MSiO2 shells (70-80 nm in thickness) with radial pores are evenly coated on the external surfaces of the SSiO2 cores (210-230 nm).The BET surface area of the prepared abrasives is 558.2 m2/g. The mesochannels (2-3 nm in pore size) in the (MSiO2) shell are perpendicular to the surface of the SSiO2 core. The topography, roughness and profile curve of silicon wafers with a SiO2 surface film of ca 1200 nm were investigated by AFM before and after chemical-mechanical polishing in the presence of abrasives. By comparison with the conventional abrasives SSiO2, the composite abrasives are in favor of decreasing the surface roughness and increasing the material removal rate of the polished wafers. The MSiO2 shells of the prepared composite abrasives may be contribute to optimize the real interfacial contact between abrasives and wafer surface through certain mechanical and/or chemical effects.
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