Structural investigation of nickel polyphosphate coacervate glass-ceramics

• Published in: RSC advances 2016-01, Vol.6 (94), p.9115-91156
• Main Authors: Franco, Douglas F, Manzani, Danilo, Barud, Hernane S, Antonio, Selma G, de Oliveira, Luiz F. C, Silva, Maurício A. P, Ribeiro, Sidney J. L, Nalin, Marcelo
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c6ra20696d

Nickel polyphosphate coacervates have been prepared through the coacervation process of sodium polyphosphate and Ni 2+ chloride solutions by the addition of different solvents with low molecular weight. The great potential of nickel polyphosphate coacervates as a material precursor was demonstrated by preparation of nickel polyphosphate glass-ceramics. Structural and spectroscopic properties were analyzed by thermal analysis, X-ray powder diffraction, Raman spectroscopic and UV-VIS techniques. Raman spectra for the nickel polyphosphate coacervates and nickel polyphosphate coacervates glass-ceramics samples shows that the addition of solvents leads to a depolymerization of the polyphosphate chains, resulting in an increase of shorter chains species based on pyrophosphates. The identification and quantification of Ni 2 P 4 0 12 , β-Ni 2 P 2 O 7 and δ-Ni 2 P 2 O 7 crystalline phases present in the nickel polyphosphate glass-ceramics were carried out by X-ray powder diffraction using the Rietveld method. Quantitative phase analyses of the three polymorph forms were also evaluated. Based on interpretation of reflectance spectroscopy and Rietveld refinement, Ni 2+ ions may occupy distorted octahedral and tetrahedral sites. Nickel polyphosphate coacervates have been prepared through the coacervation process of sodium polyphosphate and Ni 2+ chloride solutions.