Structural, thermal and dielectric properties of phosphoric acid-based geopolymers with different amounts of H₃PO₄

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• 作者：Hanen Douiri ; Soumaya Louati ; Samir Baklouti ; Mourad Arous ; Zouhir Fakhfakh
• 关键词：Geopolymers ; Thermal properties ; Dielectrics ; Proton conduction ; Dipolar relaxation
• 刊名：Materials Letters
• 出版年：1 February, 2014
• 年：2014
• 卷：116
• 期：Complete
• 页码：9-12
• 全文大小：441 K

文摘

Phosphoric acid-based geopolymers were synthesized using metakaolin (Al₂O₃-2SiO₂) and different amounts of phosphoric acid (H₃PO₄) at an ambient temperature. Structural and thermal properties of geopolymers with different molar ratios SiO₂/H₃PO₄ (Si/P =1.25, 1.5 and 1.75) were investigated to study the effect of the molar ratio SiO₂/H₃PO₄ (Si/P=1.25, 1.5 and 1.75). The results showed that an increase in the amount of phosphoric acid leads to an augment in the amorphous nature of samples and to a change in their thermal behaviors. Dielectric measurements at a range frequency of 1-10⁶ Hz revealed that the permittivity, the dielectric loss and the electrical conductivity of geopolymers at room temperature were found to be strongly dependent on the H₃PO₄ concentration. In fact, the addition of phosphoric acid improved the ionic conduction resulting in a great change in the dielectric properties.