Ligang Zhu

Luminescent properties of Tb3+ and Gd3+ ions doped aluminosilicate oxyfluoride glasses.

Tb(3+) and Gd(3+) ions doped lithium-barium-aluminosilicate oxyfluoride glasses have been prepared. The transmission, emission and excitation spectra were measured. It has been found that those Tb(3+)-doped lithium-barium-aluminosilicate oxyfluoride glasses exhibit good UV-excited luminescence. The luminescence intensity of Tb(3+) ion increases for those (Tb(3+), Gd(3+))-codoped glasses. Energy transfer process from Gd(3+) ion to Tb(3+) ion is indicated.

Research on Zr50Al15Ni10Cu25 bulk amorphous alloys prepared by mechanical alloying and low pressure sintering

Abstract Amorphous Zr50Al15Ni10Cu25 alloy powders were fabricated by mechanical alloying technique with commercially pure element powders. The effects of small amount of C, Si3N4 and SiC powders addition on the thermal stability and crystallisation behaviour of the Zr50Al15Ni10Cu25 amorphous alloy were investigated. The blended powders were compacted into bars by oil hydraulic press, and were sintered in argon atmosphere at different temperatures and pressures. The samples before and after sintering were characterised by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and electron tensile testing machine. The results demonstrated that a proper addition of Si3N4 powders to the amorphous matrix can improve the thermal stability of the matrix. Suitable additives can help to improve the density and mechanical properties of the matrix in sintering process.

Judd–Ofelt analysis and improvement in thermal stability and optical properties of Er3+ doped TeO2–ZnO–Na2O–B2O3–GeO2 glasses

Abstract Er3+ doped TeO2–ZnO–Na2O–B2O3–GeO2 glasses were elaborated by melt quenching method with powders being immersed in CCl4 that served as a reagent of dehydration. The structure has been investigated by means of Fourier transform infrared spectroscopy. Differential scanning calorimetry and thermal mechanical analysis determined thermal parameters. It is found that glasses obtained from the present work have high thermal stability against crystallisation. The difference of crystallisation temperature Tx and glass transition temperature Tg is >155°C and the thermal expansion a is in the range of 8·668×10−6–12·279×10−6°C−1. The theories of Judd–Ofelt and McCumber are applied to analyse the optical spectra. Intensity parameter Ωλ (λ = 2, 4 and 6), transition probability Aed, radiative lifetime τi and branching ratio β of the Er3+ transitions were obtained. The emission cross-sections σemis of Er3+:4I13/2→4I15/2 transitions have been calculated. All the above parameters indicate that the properties of Er3+ doped TeO2–ZnO–Na2O–B2O3–GeO2 glasses have been improved effectively in the present work. The glass can be used as ideal material for optical amplifiers.