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Boron-phosphate glasses combine the properties of phosphate glasses such as high solubility for rare-earth ions and excellent optical properties with the high thermal, chemical and mechanical properties introduced by boron oxide [1]. The obtaining and properties of boron-phosphate glasses doped with cobalt oxide are investigated in this work. The glass was prepared by classical melting-quenching method but using the wet preparation of raw materials [1]. The amount of CoO was of 0.5 and 3.0 mol% and the melting temperature of 1300 °C for 2h. UV VIS transmittance shows a minimum in the domain of 500-700 nm. The FTIR maxima are attributed to the stretching vibrations of the P-O-P bonds in units Q2 and Q1 at 770 and 870-890 cm-1 respectively and to the symmetrical and asymmetrical stretching of the PO32- units at 1030 and 1220 cm-1, respectively. The vibrations of O3B-O-BO4 bonds can be identified at 770 cm-1 and asymmetric vibrations of O3B-O-B-O bonds in triangular borate units (BO3 and BO2O-) from piro and orthoborate groups at 1030 cm-1. The mechanical properties, hardness (H), Young's modulus (E) and fracture toughness (KIC) of boron phosphate glasses, evaluated by micro- and nanoindentation techniques, showed higher values than those for alumino-phosphate glasses. DSC analyze of samples thermal treated at 800 and 900 °C indicates the crystallization temperatures around 660 and 790oC for the XRD identified crystalline compounds Al(PO3)2 and BPO4. The magnetic susceptibility values lies between 1.8 x 10-5 emu / g / Oe and 9.5 x 10-5 emu / g / Oe, directly proportional to Co oxide concentration.

References

1. B.A. Sava, Lucica Boroica, M. Elisa, O. Shikimaka, D. Grabco, M. Popa, Z. Barbos, R. Iordanescu, A.M. Niculescu, V. Kuncser, A.C. Galca, M. Eftimie, R.C.C. Monteiro ”Bismuth and lead oxides codoped boron phosphate glasses for Faraday Rotators“ https://doi.org/10.1016/j.ceramint.2017.12.205, 2017

Acknowledgements

Supported by UEFISCDI, Romania [M-ERA. NET 7–081/2013 MAGPHOGLAS project; 4N/2016, 16470102, 5N/2016, 16400102, PN45N/2016 Core Program]; Foundation for Science and Technology, Portugal [M-ERA.NET/0010/2012 and UID/CTM/500025/2013]; Council for Science and Technological Development of the Academy of Sciences of Moldova [grant number 15.817.02.06A].