A series of novel Sn 2+ doped boroaluminate glasses were prepared by the traditional melt quenching method in this work. Their glass network structure, luminescent properties, and mechanisms were studied in detail. The main framework of the glass network was dependent on the glass network former (B 2 O 3 ) and intermediate (Al 2 O 3 ), and was characterized by the 11 B and 27 Al NMR spectra . Broadband tunable blue-violet emissions ranging from 320 to 550 nm were realized by regulating the glass network structure through optical basicity. The quantitative relationship between optical basicity and emission/excitation peak positions and intensities, FWHM, and Stokes-Shift of this Sn 2+ -doped glass were revealed, according to which the luminescent properties of Sn 2+ could be modulated and even predicted in the future. This work will enrich our understanding of the luminescent properties of Sn 2+ ions and the variations of glass network structure, guiding the design of efficient and tunable luminescent boroaluminate glass.
Chen Mao,Dong Xiaosen,Pu Shuiqiang,Tang Wenbo,Zheng Kui
Na 2 O and K 2 O alkaline oxide capacities of TiO 2 -bearing blast furnace slags are critical values for vanadium titanomagnetite blast furnace operation. In this study, high-temperature experiments with fast-quenching were conducted to investigate the effects of TiO 2 concentration, basicity, MgO and Al 2 O 3 concentrations on Na 2 O and K 2 O concentrations in the TiO 2 -bearing blast furnace slags. The results were correlated with optical basicity and also compared with the plant data from one commercial vanadium titanomagnetite blast furnace.
Chenguang Li,Chenbiao Lai,Yaoyan Wu,Hanxiang Ouyang,Junbin Sun,Weihong Lu
Alumina based rare earth oxides ceramic materials, with the good performance against the CMAS corrosion, were widely used as the thermal/environmental barrier coatings. In this work, three Y 2 O 3 –Al 2 O 3 binary ceramic bulks, which were the Y 3 Al 5 O 12 , YAlO 3 and Y 4 Al 2 O 9 , were prepared by high temperature solid state reaction using the Y 2 O 3 and Al 2 O 3 as the raw materials. The resistances to CMAS corrosion of these materials at 1250 °C and 1350 °C were compared fully. The compositions and structures of the samples before and after corrosion were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the different chemical compositions of the materials resulted in the different optical basicity (OB) values which can decide the reactivity of the material with the CMAS melts. The Y 3 Al 5 O 12 ceramic material was inert to the CMAS for its low OB value of 0.75 and damaged seriously by the CMAS through physical penetration. The YAlO 3 and Y 4 Al 2 O 9 with the high OB values of 0.80 and 0.87 reacted with the CMAS to form the Ca 4 Y 6 (SiO 4 ) 6 O. The YAlO 3 ceramic bulk exhibited the good performance against the CMAS corrosion benefitting from the formation of the Ca 4 Y 6 (SiO 4 ) 6 O and the CaAl 2 Si 2 O 8 .
Bi-doped zinic silicate glasses (SG) and germanate glasses (GG) were prepared and the relationship between Bi near infrared (NIR) luminescence and the glass structures were investigated. The absorption, visible luminescence, and X-ray photoelectron spectroscopy (XPS) spectra revealed that the lower valence state of Bi ions containing NIR active centers increased with the decrease of optical basicity in the two sets of glasses. However, the NIR emission in these glasses cannot be merely explained by the theory of optical basicity. In the SG glasses, there is no obvious structural change, the NIR luminescence can be well interpreted by theory of optical basicity. But there is a distinct transformation in the GG glasses, the abnormal fluorescence phenomenon can be connected with the local structure regulating effect. The mechanisms of the NIR emission and local structure regulating effect were discussed.
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