Development of lutetium oxide continuous fibers with excellent mechanical properties

The difficulty of reducing the diameter of lutetium oxide(Lu_(2)O_(3))continuous fibers below 50μm not only limits the flexibility of the sample but also seriously affects their application and development in high-energy lasers.In this work,a Lu-containing precursor with high ceramic yield was used as raw material,fiberized into precursor fibers by dry spinning.The pressure-assisted water vapor pretreatment(PAWVT)method was creatively proposed,and the effect of pretreatment temperature on the ceramization behavior of the precursor fibers was studied.By regulating the decomposition behavior of organic components in the precursor,the problem of fiber pulverization during heat treatment was effectively solved,and the Lu_(2)O_(3) continuous fibers with a diameter of 40μm were obtained.Compared with the current reported results,the diameter was reduced by about 50%,successfully breaking through the diameter limitation of Lu_(2)O_(3) continuous fibers.In addition,the tensile strength,elastic modulus,flexibility,and temperature resistance of Lu_(2)O_(3) continuous fibers were researched for the first time.The tensile strength and elastic modulus of Lu_(2)O_(3) continuous fibers were 373.23 MPa and 31.55 GPa,respectively.The as-obtained flexible Lu_(2)O_(3) continuous fibers with a limit radius of curvature of 3.5-4.5 mm had a temperature resistance of not lower than 1300℃,which established a solid foundation for the expansion of their application form in the field of high-energy lasers.

Nanometric polishing of lutetium oxide by plasma-assisted etching

Plasma-assisted etching,in which the irradiation of hydrogen plasma and inorganic acid etching are integrated,is proposed as a novel polishing method for sesquioxide crystals.By means of this approach,low damage and even damage-free surfaces with a high material removal rate can be achieved in lutetium oxide surface finishing.Analysis of transmission electron microscopy and X-ray photoelectron spectroscopy reveal that plasma hydrogenation converts the sesquioxide into hydroxide,which leads a high efficient way to polish the surfaces.The influences of process conditions on the etching boundary and surface roughness are also qualitatively investigated using scanning electron microscope and white light interferometry.The newly developed process is verified by a systematic experiment.

Infrared spectroscopy analyses of air-CH_4 or air-CO gas flows interacting with polycrystalline CeO_2, La_2O_3 and Lu_2O_3 oxides

A comparative study of reactivity between air-CH4 or air-CO gas flows and CeO2, La2O3 and Lu2O3 rare earth oxides was per- formed using Fourier transform infrared spectroscopy analyses of CO2 gas resulted from the conversion of CH4 or CO gases. Polyerystalline samples of CeO2, La2O3 and Lu2O3 were first prepared by specific precipitation methods followed by low temperature calcination process. In the case of Lu2O3 oxide, a new specific route was proposed. Crystallite dimensions were determined by X-ray diffraction and transmission electron microscopy analyses. Morphologies were characterized using scanning electron microscopy. Specific surface areas were determined from Bnmauer-Emmett-Teller （BET） technique. Using infrared spectroscopy analyses, the conversion rates of CH4 or CO into CO2 were de- termined from the evolutions of CO2 vibrational band intensities, as a function of time and temperature. It was dearly established that, despite its low specific surface, the Lu2O3 oxide presented the highest capacity of conversion of CH4 or CO into CO2.

Characterization and photoluminescence of Lu_2O_3-Eu^(3+) nano-phosphor prepared by modified solution combustion method

Nanoscale Lu2O3：Eu3＋ phosphor was prepared by a modified solution combustion method using urea and acrylamide monomer.The particle sizes and photoluminescent properties of nano-phosphor were closely related to the molar ratio of urea-to-RE nitrates and acrylamide monomer-to-RE nitrates.The as-prepared samples with the sizes of 9.6-11.6 nm were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy and energy dispersive spectrometer.Lu2O3：Eu3＋ nano-phosphor that depicted high photoluminescence in the size around 10 nm was reported.Compared with the sample prepared by solid state reaction,the photoluminescence of sample was increased sufficiently to be 45.1%.The emission spectra of the samples presented the typical emission from 5D0 level to 7FJ（J=0,1,2,3,4） level of the Eu3＋ ion.