Research Journal of Chemical Sciences ______________________________________________ ISSN 2231-606X Vol. 4(2), 38-41, February (2014) Res. J. Chem. Sci. International Science Congress Association 38 Chemical Degradation Study of Sodium Borophosphate Glasses Amit L. Patil, Umakant B. Chanshetti and Pravin S. Bhale Department of Chemistry, Arts, Science & Commerce College, Naldurg, Tq-Tuljapur Dist.- Osmanabad- 413602, MS, INDIA Available online at: www.isca.in, www.isca.me Received 28th December 2013, revised 18th January 2014, accepted 9th February 2014Abstract Sodium borophosphate glasses of the series of 30NaO – (70-x) B – xP (x=15, 20, 25, 30, 35,..) have been prepared by melt-quench technique. The glass samples were characterized using X-ray diffraction (XRD) and chemical degradation (corrosion) techniques. The X-ray diffraction pattern confirms the amorphous nature of the glass samples. Chemical degradation studies of the glass samples were carried out in 10% HCl and 10% NaOH. The dissolution rate was seen to be higher in acidic medium as compared to alkaline medium. Keywords: Sodium borophosphate glasses, XRD, chemical degradation, glass composition, glass former. Introduction In the material science literature, there is a wealth of information on glass degradation. Boron oxide (B) usually occurs in the glassy from which is virtually in capable of direct crystallization. Pure boron trioxide (B) is a very good glass former, covalently bonded with interesting physico chemical properties. It exhibit unique structural features and attracts because of it simple composition which consists of planar BOtriangle1,2. Glasses having P5 as one of the major component are called phosphate glasses. Phosphorous pentaoxide is used as a glass former. Pure P has a melting point of 560C and a boiling point of 605C. Phosphate glasses have poor durability which often limits their practical applications, that is generally overcome by adding certain oxides to the phosphate glasses, such as PbO, Al and Fe. In phosphate network the addition of alkali ions depolymerizes the phosphate network and decreases the connectivity. A similar increase was observed in NaO, SiO glasses with the addition of Al3 . The pure phosphate glasses are highly hygroscopic. However, the alkali oxides and other additives modified phosphate glasses were reported to stable and durable. The non linear optical properties of semiconductor doped glasses, in which the semiconductor microcrystal from quantum dots has been a topic of recent theoretical5,6 and practical interest7,8. Phosphate glasses have high IR transmission nearly up to 8 mm, because of low thermo-optical coefficients and large emission they are more suitable for high power lasers10. Phosphate glasses have many applications in optics and other areas. Researchers have studied wide variety of phosphate glass compositions. P is main glass former gives with (NaO) sodium oxide modifier gives phosphate glasses with good physical properties and high UV transmission. Alkali borophosphate glasses are of interest for fast ion conducting applications. Material and Methods Glass preparation: The Sodium borophosphate glasses of various compositions were prepared by melt quench technique. The chemicals were use NaNO, HBO3 and (NHHPO4 of analytical grade. These chemicals were thoroughly mixed and ground for 30-40 min in a mortar pastel and then the charge 30g was melted in alumina crucible using muffle furnace for 4-5 hrs at temperature ranging from 900-1100°C depending on composition. Glasses with compositions 30NaO – (70-x) B– xP (x=15, 20, 25, 30, 35,..) XRD- Analysis: Prepared glasses were characterized by X-ray diffraction technique to check amorphous nature of glasses, using X-ray diffractometer with Cu-K radiation. The XRD patterns were recorded in the 2 range 20-80 degree with scanning rate 1/mint. Chemical Degradation: The result of the corrosion test for the polished samples of sodium borophosphate glasses were carried out in 10% NaOH and 10% HCl solutions at room temperature for 1hrs to 6hrs of exposure are monitored. Results and Discussion XRD Analysis: Prepared glasses were characterized by X-ray diffraction technique. Figure 1 shows the XRD pattern of the samples of sodium borophosphate glasses indicate that the broad peaks, characteristic of glass structure. This is the clear indication of amorphous nature within the resolution limit of XRD instrument. Chemical Degradation: The result of the corrosion test for the polished samples of sodium borophosphate glasses were carried out in 10% NaOH and 10% HCl solutions at room temperature for 1hrs to 6 hrs of exposure are shown in table 1 and table 2. Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(2), 38-41, February (2014) Res. J. Chem. Sci. International Science Congress Association 39 The dissolution rate was seen to be higher in acidic medium as compared to alkaline medium. In 10% HCl solution, the rate of dissolution of for glass II-3 i.e. 30NaO-45B-25P is maximum and for glass II-1 i.e. 30NaO-55B-15P5 is less in all the studied glass samples of sodium borophosphate glasses. In 10% NaOH solution, the dissolution rate is very slow, for II-1 glass than the II-2 and II-3. From the studies of chemical degradation it came to notice that the rate of dissolution of II-1 glass in both i.e. in 10% HCl and in 10% NaOH is low in comparison to other investigated sodium borophosphate glasses. In 10% HCl solution, the rate of dissolution of for glass II-3 i.e. 30NaO-45B-25P5 is maximum and for glass II-1 i.e. 30NaO-55B-15P5 is less in all the studied glass samples sodium borophosphate glasses. The investigated glasses contain group I (Periodic Table) fluxes i.e. Na and glass former B, which help to improve the chemical resistance hence the rate of dissolution in NaOH solution is slower than in HCl.Plot of weight loss versus Pcontent at various time of exposure in 10% HCL is shown in figure 2 and the Plot of weight loss versus P content at various time of exposure in 10% NaOH is shown in figure 3. 203040506070802004006008001000120014001600180020002200 Intensity (a.u.)qq (degree) II-3Figure-1 X-ray diffraction patterns for typical sample II-3 (X=25%) Table-1 Weight loss observed in 10% HCl for 1 to 6 hrs of exposure of 30NaO – (70– x) B3 – xP5 glasses Sr. No Glass Code Composition X mole% of P 2 O 5 Wt. loss in 10% HCl g/cm 2 1 hrs 2 hrs 3 hrs 4 hrs 5 hrs 6 hrs 1 II-1 15 0.31 0.58 0.79 0.92 0.97 0.90 2 II-2 20 0.40 0.59 0.81 0.93 0.99 0.94 3 II-3 25 0.38 0.58 0.82 0.88 0.94 0.91 Table-2 Weight loss observed in 10% NaOH for 1 to 6 hrs of exposure of 30NaO – (70– x) B3 – xP5 glasses Sr. No. Glass Code Composition X mole% of P5 Wt. loss in 10% NaOH g/cm2 1 hrs 2 hrs 3 hrs 4 hrs 5 hrs 6 hrs 1 II-1 15 0.08 0.012 0.019 0.031 0.042 0.038 2 II-2 20 0.010 0.014 0.022 0.040 0.048 0.045 3 II-3 25 0.014 0.017 0.030 0.039 0.051 0.048 Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(2), 38-41, February (2014) Res. J. Chem. Sci. International Science Congress Association 40 141618202224260.30.40.50.60.70.80.91.0 Wt. loss in 10% HCl g/cm2Mol % of P 1 hr 2 hrs 3 hrs 4 hrs 5 hrs 6 hrsFigure-2 Plot of weight loss versus P content at various time of exposure in 10% HCl. 141618202224260.000.010.020.030.040.050.060.070.080.09 Wt. loss in 10% NaOH g/cm2Mol % of P 1 hr 2 hrs 3 hrs 4 hrs 5 hrs 6 hrsFigure-3 Plot of weight loss versus P content at various time of exposure in 10% NaOH Conclusion The XRD pattern of various Sodium borophosphate glasses confirms the amorphous nature of glasses. The investigated glasses contain Na and glass former B, which help to improve the chemical resistance hence dissolution rate was seen to be higher in acidic medium as compared to alkaline medium at room temperature. In alkaline medium percentage of Pincreases dissolution rate also goes on increases. 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