Degradation study on ternary zinc magnesium phosphate glasses

Abstract

Glasses with composition (ZnO)30(MgO) x (P2O5)70−x (x = 5, 8, 10, 13, 15, 18, and 20 mol.%) have been successfully prepared by the melt-quenching technique. Degradation study has been carried out by means of measuring their chemical durability against buffer solutions with initial pH values of 4.01, 7.00, and 10.01 at an ambient temperature for up to 30 days. The dissolution rate (D R) was obtained by calculating the measured weight loss of the glasses per unit surface area per unit immersion time. The results show that the glasses have better corrosion resistance in basic solution. It was also found that the weight loss is related to the MgO concentration with lower P2O5 concentration exhibiting greater corrosion resistance irrespective of acidic, neutral, or basic solutions as immersion liquid. All the sample surfaces and edges were corroded and the solutions experienced a decrease in pH values during the duration of the corrosion test.

Characterisation of CorGlaes® Pure 107 fibres for biomedical applications

“…This is due to the expected strong ionic cross-linking in the phosphate network structure from the inclusion of Mg 2+ , Zn 2+ and Ca 2+ cations and their respective charge-to-size ratios (0.0232, 0.0227 and 0.0175). The network structure would then be more capable of suppressing the onset of crystallisation in line with previous results [ 20 , 33 , 36 , 37 ]. However, previous studies have also shown that increased network stability is associated with a higher T g due to the increased energy required to fracture the structural bonds that contradicts the comparatively low T g found in these results.…”

“…However, previous studies have also shown that increased network stability is associated with a higher T g due to the increased energy required to fracture the structural bonds that contradicts the comparatively low T g found in these results. However, this could be accounted for by the general decrease in T g found in ultraphosphate glasses compared to metaphosphate compositions as reported by Ahmed et al [ 12 , 20 , 34 , 37 ]. Based on previous metaphosphate glass compositions studied by Morikawa et al [ 34 ], the large PW may also be attributed to a mixed cation effect between the Mg 2+ and Ca 2+ ions.…”

“…Such compounds would correlate with the ionic constituents of the CorGlaes ® Pure 107 composition and have been previously reported to precipitate during PG dissolution [37, 63]. These phases are expected to form via hydrolysis mechanisms with the observed decrease in media pH over the immersion period resulting from the phosphoric acid (H 3 PO 4 ) dissolution by-product [37, 63]. However, the precise identification of each amorphous phase from the available FTIR/Raman spectra is restricted due to the similar IR signals of these salts and associated band overlapping.…”

Structure and dissolution behavior of MgO–P₂O₅–TiO₂/Nb₂O₅ (Mg/P ≥ 1) invert glasses

“…Franks et al 15) and Lee et al 18) reported that the dissolution rate of MgOCaO Na 2 OP 2 O 5 glasses within the metaphosphate region decreased with increasing the MgO content. Smith et al 20) and Khor et al 17) reported that the chemical durability of MgOZnOP 2 O 5 glasses in near the metaphospate region was improved by increasing the MgO content in the glasses. In our previous work, the chemical durability of CaOP 2 O 5 TiO 2 metaphosphate glasses improved with the addition of MgO, while that of the invert glasses decreased when CaO was substituted by MgO.…”

Structural and optical properties of CuO in zinc phosphate glasses and effects of gamma irradiation

“…However, the introduction of another divalent oxide as MgO has been shown to reduce corrosion rates in aqueous solutions on zinc phosphate glasses [9]. This behavior has been related to some reasons such as the formation of more chemically resistant P-O-Mg bond, or to the decrease of P 2 O 5 content or to the introduction of dual two divalent oxides which can form MO 4 groups and block the pathway for the progress of the process corrosion [10,11].…”