Study On Preparation And Properties Of Oxyfluoride Germanate Glass

Germanate glass has lower phonon energy, wider range of the infrared transmission and good ability of glass formation, so it has broad application prospects in IR window materials. Compared with other IR materials, Germanate glass is easy to prepare, and it has good chemical stability, thermal shock resistance, high IR transmittance and so on. This work introduced oxyfluoride germinate and germanosilicate glass system as the matrix, and focused on two research points. One point was to research on the effects of near-infrared absorbing of OH after the introduction of fluoride, and do comparation with the silicate glass system. The other point was to develop a kind of rare earth ions doped luminescence glasses which possessed high rare earth ions solubility, high luminescence efficiency, could emit orange ligh under UV or violet light excitation and had potential application in phosphor and light conversion films.First, this thesis reviewed the studies of three aspects as following: (i) application fields of germanate glass, (ii) progress of rare earth ions doped germanate glass, and (iii) situation of oxyfluoride glass-ceramics. Second, the non-doped, rare earth ions doped luminescence glasses and rare earth ions doped luminescence oxyfluoride silicate, germinate and germanosilicate glass ceramics were prepared by melting-annealing/ quenching/ thermal treatment method. The micro-structure, optical and thermal properties were measured by XRD, DTA, Abs, PL and so on. The details were listed as following:(1) We selected suitable temperature rules, got oxyfluoride silicate, germinate glass with good melting quality, high visible-IR transmittance by melting and annealing method. The introduction of fluoride, reduced the melting temperature of glass system. Generally, the melting temperature of silicate glass is above 1600°C, while the melting temperature of oxyfluoride silicate, germinate glass we prepared were 1550°C and 1500°C respectively. There is no strong absorption around 1.5μm. but excellent visible-IR transmittance through the test of transmission spectrum. So it is a kind of potential near-infrared window materials. (2) The effects of alkali ions on Sm ion doped oxyfluoride glass and quenching concentration were investigated. SK. has the strongest luminescence intensity among silicate glass system, with the quenching concentration 1.5%. While GL has the strongest luminescence intensity among germanate glass system, with the quenching concentration 2.5%. Germanate glass system has higher rare earth ions solubility and quenching concentration.(3) The effects of heat treatment temperature on structure and luminescence performance of SK10 glass were investigated. There are obvious crystallization peak in XRD spectra which is mainly attributable to Ba₃AlF₉ phase after the sample finished heat treatment at 660°C for 4 hours. While samples with heat treatment at 700°C for 4 hours became opaque, which is due to coexist of Ba₃AlF₉ phase and BaAl₂Si₂O₈ phase. The effects of heat treatment time on structure and luminescence performance of GL20 glass were also investigated. With the extension of heat-treatment time, the peak intensity of crystallization peak increased. Ba₃AlF₉ phase is helpful to luminescence intensity increases. After 6 h heat treatment, transmittance of the sample decreased.(4) The structure of germanosilicate glass loosed, softening temperature and crystallization temperature decreased, rare earth ions solubility increased, with the increase of the content of germanium oxide in the germanosilicate glass. While GSK32 has the strongest luminescence intensity among germanosilicate glass system. There are two reasons: (i) high rare earth ions solubility and (ii) rare earth ions in this matrix had a uniform dispersion.(5) The effects of rare earth ions content on luminescence performance of glass-ceramics were studied. It was found that concentration of the Sm ions increased from 1 mol % to and 2 mol %, Ba₃AlF₉ appeared after heat treatment. When the concentration of the Sm ions was 3 mol %, there was no crystalline phase in the glass matrix after the heat-treatment. And its luminescence intensity decreased.