Influence of pH and microwave calcination on the morphology of KGd(WO4)2 particles derived by Pechini Sol–Gel method

• Published in: Journal of sol-gel science and technology Vol. 58; no. 2; pp. 419 - 426
• Main Authors: Thangaraju, D., Moorthy Babu, S., Samuel, P., Durairajan, A., Hayakawa, Y.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.05.2011; Springer; Springer Nature B.V
• Subjects: Binders; Carbon content; Ceramics; Chemistry; Chemistry and Materials Science; Citric acid; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Composites; Deionization; Ethylene glycol; Exact sciences and technology; Gadolinium; Gels; General and physical chemistry; Glass; Heat treatment; Infrared analysis; Infrared spectroscopy; Inorganic Chemistry; Materials Science; Microwaves; Morphology; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper; Photomicrographs; Prepolymers; Ribbons; Scanning electron microscopy; Sol-gel processes; Spectrum analysis; Synthesis; Tungsten; Laser materials; Stimulated Raman scattering; Sol–gel materials processing; Water; Ethylene; Microwave; Gadolinium; Oxides; Tungstates; Precursor; Powder; Particle; Synthesis; Carbon content; Tungsten; pH; Scanning electron microscopy; Potassium nitrate; Transition metal; Crystallinity; Binders; Complexes; X ray diffraction; Sol-gel materials processing; Citric acid; Infrared spectrometry; Sol gel process; Complexing agent; Morphology; Laser; Glycol
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-011-2408-9

KGd(WO 4 ) 2 (KGW) particles were synthesized at 3.5, 5.5 and 7.5 pH values by Pechini polymeric complex sol–gel method using potassium nitrate, gadolinium nitrate, ammonium paratungstate, citric acid and ethylene glycol as starting materials. Deionized water was used as solvent. Polymeric precursor gel was formed with citric acid as complexing agent and ethylene glycol as binder. Synthesized gel was analyzed by FT-IR spectroscopy. Prepared precursor gels were further annealed using resistive and microwave processes at 550 and 700 °C, respectively. The properties of heat treated samples were characterized by powder XRD, FT-IR, Raman and SEM analysis to understand the crystallinity, organic liberation, tungstate ribbon formation and surface morphology, respectively. The phase formation and different phases of intermediate oxides in pre-fired samples were investigated by powder XRD. Organic liberation in the samples in relation to temperature, and the carbon content in the pre-fired powder was analyzed using FT-IR spectrum. Raman spectrum reveals the formation of tungsten ribbons as well as the quality of the samples. The morphological changes at different synthesis conditions were observed with SEM micrographs.