An evaluation on sol-gel chemical processing of refractory barium hexa aluminate fibrous structures

An evaluation on sol-gel chemical processing of refractory barium hexa aluminate fibrous structures

In this research barium hexa aluminate fibrous refractory products were produced by a chemical processing route. Boehmite was used as aluminum precursor while barium nitrate was used as barium precursor and the final solution had made according to stoichiometric BaO.6Al2O3 composition. It was found that two different gels could be obtained during this route. Mainly the secondary gel was trapped into the initial gel structure. Finally gels were heated at various temperatures (1350, 1650℃) to following the formation of the barium hexa aluminate in fibrous structure due to sintering. Then the crystallization of transitional phases such as 3BaO.Al2O3 and BaO.Al2O3 to BaO.6Al2O3 were followed at different sintering temperatures by X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy. Also scanning electron microscopy (SEM) was used to study the microstructural changes and micrographies. The produced gels were characterized by thermo gravimetrical and differential thermal analysis (TG/DTA). The results showed that BaO.6Al2O3 was the major phase at higher temperatures and fibrous structure appeared in final samples.

In this research barium hexa aluminate fibrous refractory products were produced by a chemical processing route. Boehmite was used as aluminum precursor while barium nitrate was used as barium precursor and the final solution had made according to stoichiometric BaO.6Al2O3 composition. It was found that two different gels could be obtained during this route. Mainly the secondary gel was trapped into the initial gel structure. Finally gels were heated at various temperatures (1350, 1650℃) to following the formation of the barium hexa aluminate in fibrous structure due to sintering. Then the crystallization of transitional phases such as 3BaO.Al2O3 and BaO.Al2O3 to BaO.6Al2O3 were followed at different sintering temperatures by X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy. Also scanning electron microscopy (SEM) was used to study the microstructural changes and micrographies. The produced gels were characterized by thermo gravimetrical and differential thermal analysis (TG/DTA). The results showed that BaO.6Al2O3 was the major phase at higher temperatures and fibrous structure appeared in final samples.