Study of Sodium-Chromium-Iron-Phosphate Glass by XRD, IR, Chemical Durability and SEM

Abstract

Chromium iron phosphate glass was investigated for use as waste form because of its improved chemical durability. The introduction of chromium in sodium-iron-phosphate glass is used to compare its effect with iron in inhibition of corrosion. The sodium-chromium-iron phosphate glass of composition 10Na 2 O-30Fe 2 O 3 -5Cr 2 O 3 -55P 2 O 5 (mol%) was produced by melting batches of (99, 98% pure) Cr 2 O 3 , Fe 2 O 3 , Na 2 CO 3 , and (NH 4 ) 2 HPO 4 at 1080˚C for one hour and pouring the liquid into steel mold. The sample was annealed at 680˚C for 48 h. We have performed the measurement of X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), Infra-Red spectroscopy (IR), and the chemical durability. The IR of the glass studied, contains two dominant bands, which were characteristic of pyrophosphate groups, (P-O) stretching mode of P-O non bridging oxygen at 1055 cm −1 and sym stretching mode of bridging oxygen at 444 cm −1 respectively. There is also a band at 603 cm −1 attributed to isolated tetrahedral units (PO 4 ) 3− . The chemical durability of the glass was investigated by measuring the weight loss in distilled water at 90˚C for 22 days.

Chemical Durability, Properties and Structural Approach of the Glass Series xFe<sub>2</sub>O<sub>3</sub>-(45-x) PbO-55P<sub>2</sub>O<sub>5</sub> (with 0 ≤ x ≤ 20; mol%)

“…3 content increased, this increase characterizes a strengthening of the vitreous networks[8] [14][16] [17]. This behavior has been confirmed by previous work[14].…”

Phase composition, structure, and hydrolytic durability of glasses in the Na2O-Al2O3-(Fe2O3)-P2O5 system at replacement of Al2O3 by Fe2O3

“…The absorption bands in the ranges 700-800 and 900-950 cm -1 belong, respectively, to the symmetric and antisymmetric stretching vibrations of the bridging P-O-P and P-O-Al bonds linking the РО 4 tetrahedra with each other and with AlO 4 tetrahedra. The absorption bands in the ranges 950-1050, 1050-1150, 1150-1250, and 1250-1350 cm -1 correspond to vibrations of the О-Р-О bonds in the РО 4 tetrahedra with 0, 1, 2, and 3 bridging oxygen atoms, respectively, and those in the range 1300-1400 cm -1 , to vibrations of Р=О double bonds [13][14][15][16][17][18][19][20][21][22][23]. In the ranges 3400-3800 and 1450-1600 cm -1 , there are also weak absorption bands corresponding, respectively, to stretching and bending vibrations of the Н-О-Н bonds in molecules of adsorbed and structurally bound water.…”

Correlation between Chemical Durability Behaviour and Structural Approach of the Vitreous Part of the System 55P<sub>2</sub>O<sub>5</sub>-2Cr<sub>2</sub>O<sub>3</sub>-(43-x) Na<sub>2</sub>O-xPbO

“…The decrease in chemical durability beyond 28 mol % PbO seems to be explained by the increase of crystallites in the glass, which contain the majority of the isolated orthophosphate phases (Q 0 ). According to the IR spectra, the (Q 0 ) groups increase at the expense of both pyrophosphate groups (Q 1 ) and metaphosphates (Q 2 ) [12]. Generally an increase in crystallites in glasses causes an increase in chemical durability.…”