Thermodynamic model and structure of CaO–P2O5 glasses

The structure of xBaO·(1 − x) P 2 O 5 (x = 0.30, 0.35, 0.40, 0.45, and 0.50) glasses was studied by Raman spectroscopy and thermodynamic model Shakhmatkin and Vedishcheva (SVTDM). The seven system components (defined as stable crystalline phases of the BaO-P 2 O 5 binary phase diagram) were considered in the SVTDM: BaO, P 2 O 5 , 4BaO·P 2 O 5 (B4P), 3BaO·P 2 O 5 (B3P), 2BaO·P 2 O 5 (B2P), BaO·P 2 O 5 (BP), and BaO·2 P 2 O 5 (BP2). Only the equilibrium molar abundances of BP and BP2 were non-negligible in all studied glass compositions. Therefore, in the next step, multivariate curve analysis (MCR) of the baseline-subtracted, thermally-corrected experimental Raman spectra, was performed for two components (BP2 and BP). MCR resulted in the Raman spectra (loadings) and relative abundances (scores) of each considered component. The MCR method reproduced 98.93% of the spectral data variance. Then, the decomposition of Malfait was used. The perfect fit between the MCR loadings and the partial Raman spectra of BP2 and BP, obtained by Malfait's decomposition, was found, confirming the validity of thermodynamic model.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Section: Introductionmentioning

confidence: 79%

Section: Thermodynamic Model Of Shakhmatkin and Vedishchevamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structure and Raman spectra of binary barium phosphate glasses

Hruška

Dagupati

Chromčíková

et al. 2020

“…TDM-SV can be used to interpret the composition-structure-property relationships for a variety of multi-component glass-forming systems [12][13][14][15][16][17][18][19]. On the other hand, the model has to be checked by the comparison of its results with the structural data for various glasses and melts [17][18][19][20][21]. In our previous work [20,[22][23][24] we showed that the statistical analysis of the Raman spectra validated the TDM-SV for the Na 2 O-B 2 O 3 , CaO-P 2 O 5 , and ZnO-P 2 O 5 binary glass systems.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic model and Raman spectra of MgO–P2O5 glasses

Hruška

Dagupati

Chromčíková

et al. 2020

The structure of binary glasses xMgO·(1−x)P2O5 (x = 0.30, 0.35, 0.40, 0.45, 0.50, and 0.55) was studied by thermodynamic model (TDM) of Shakhmatkin and Vedishcheva (SV) and Raman spectroscopy. In the TDM, six following system components were considered: MgO (M), P2O5 (P), MgO·2P2O5 (MP2), MgO·P2O5 (MP), 2MgO·P2O5 (M2P), 3MgO·P2O5 (M3P). The principal component analysis (PCA) of experimental Raman spectra resulted in three independent components. The baseline subtracted and thermally corrected Raman spectra were analyzed by the multivariate curve analysis (MCR) for three components. The MCR resulted in the Raman spectra and relative abundance of each component. The experimental spectra were reproduced by the MCR on the level of 99.9%. Correlation analysis attributed the MCR components to M2P, MP, and MP2. Then the Malfait’s decomposition was performed based on the TDM-SV equilibrium molar amounts of system components (MP2, MP, and M2P) resulting in partial Raman spectra (PRS). Normalized MCR loadings coincide with normalized PRS. Adjusted scores were reproduced with good accuracy equilibrium molar amounts of system components.

“…The aim of the study was the validation of the thermodynamic model of Shakhmatkin and Vedishcheva [8][9][10][11][12][13][14] by its application in the spectral decomposition by the method of Malfait. In our previous work [15], the Shakhmatkin and Vedishcheva model was successfully used for reproducing the Q-distribution in CaO-P 2 O 5 glasses measured by 31 P MAS NMR [4]. Despite the more sophisticated and more complex thermodynamic models were used for study of phosphate glass-forming melts, e.g., the two sublattice model [5], the Shakhmatkin and Vedishcheva model is appealing for its simplicity and the fact that it does not contain any adjustable parameters.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic model and Raman spectra of CaO–P2O5 glasses

Chromčíková¹,

Liška²,

Zemanová³

et al. 2015

The structure of glasses of the binary system CaO-P 2 O 5 was investigated by the comparison of the results of the thermodynamic model of Shakhmatkin and Vedishcheva constructed using the molar Gibbs energies obtained from the FACT database with the results obtained by the analysis of Raman spectra of xCaOÁ(100 -x)P 2 O 5 (x = 35, 40, 45, 50, 55) glasses performed by the principal component analysis (PCA) method and spectral decomposition by the method of Malfait. The PCA method identified three independent components in the studied spectral series. On the other hand, the thermodynamic modeling resulted in three components with significant abundance in the studied glasses, i.e., P 2 O 5 , CaP 2 O 6 , and Ca 2 P 2 O 7 . Using the method of Malfait, partial Raman spectra of P 2 O 5 , CaP 2 O 6 , and Ca 2 P 2 O 7 were calculated. The experimental spectra were reproduced with very good accuracy. The multivariate curve resolution (MCR) method was used for the analysis of the experimental spectra. It was found that MCR loadings are practically identical with the partial Raman spectra obtained from the results of thermodynamic model by the method of Malfait. All the obtained results confirmed the structural information acquired from the thermodynamic model.