Papers by Keyword: LaPO₄

Abstract: The present paper reports on the structural properties of Lanthanum Phosphate (LaPO4) nanostructure film in term of its surface morphology. In this study, the LaPO4 samples were prepared by sol-gel spin coating method with different layers. Photoluminescent (PL) properties of the samples were investigated using FluoroMax-4 Spectrofluorometer - Horiba Scientific at room temperature with excitation spectra 254 nm. While its physical structural properties was investigated using atomic force microscopy (AFM-XE100).

Abstract: One-dimensional (1D) nanowire is one of the most important components for nanosized electronic devices’ development, sensors. Eu3+-doped lanthanum phosphate nanowire has been synthesized via hydrothermal method. The sample is characterized using XRD and SEM; SEM images show the diameter of LaPO4:Eu3+ nanowires before heat treatment is about 10 nm. After sinter, the LaPO4:Eu3+ nanowire becomes particles. The particles grow up and the luminescence intensity becomes lower with the sintering temperature going higher, while the life time of 5D0→7F1 transition is longer. It is suppose that the perfect lattice is not benefit to the dopant ions into.

Abstract: Nanometer LaPO4 powders were synthesized by liquid-liquid direct precipitation method. La(NO3)3•6H2O and (NH4)3PO4•3H2O were used as raw materials. The calcining temperature was 900°C, 1000°C, 1100°C, respectively. DTA result shows that the LaPO4 precursor is LaPO4•4H2O. The calicined powders were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscope (SEM), and exhibited a pure LaPO4 phase with a monazite structure about 50-100 nm in diameter size. With the calcining temperature increasing, the crystallization of the LaPO4 became better and the grain shape changed from elongated grain shape to spherical grain shape.

Abstract: LaPO4-ZrO2 composites were prepared by slip casting and pressureless-sintered in air. The effects of LaPO4 addition on microstructure and thermal shock resistance were addressed. The thermal shock resistance of the composites was evaluated by air quenching and a subsequent three-point bending test to determine the strength degradation. Comparisons were made with results from parallel experiments conducted using a ZrO2 ceramic without LaPO4 additions. The reference ZrO2 ceramic showed the expected substantial strength losses when thermally quenched from 470oC above room temperature. By contrast, the LaPO4-ZrO2 ceramics, while displaying reduced strength relative to the reference ZrO2 ceramics, exhibited minimal strength degradation under severe thermal shock conditions.

Abstract: Spark plasma sintering was used to fabricate the LaPO4 ceramics and the effect of SPS holding time and sintering temperature on the densification and texture of LaPO4 ceramics were studied. The results revealed that holding time had no obvious influence on the densification of LaPO4 ceramics under the present process. The density increases with the increase of sintering temperature, when it reached 1350°C, the relative density kept nearly constant of 98.6 %. The preferred orientation of LaPO4 ceramics approximately increases with the increase of sintering temperature, but contrary impact in holding time.

Abstract: Some useful characteristics, including strength, toughness, damage of machining, and propagation pattern of indentation cracks, were studied based on machinable 30 wt%LaPO4/ Al2O3 composites. Corresponding characteristics for Al2O3 ceramic were also concerned for comparing. The results supplied some elementary information for both use and further study of LaPO4/ Al2O3 composites.