Molten salt synthesis of mullite nanowhiskers using different silica sources

• Published in: International journal of minerals, metallurgy and materials Vol. 22; no. 8; pp. 884 - 891
• Main Authors: Yang, Tao, Qiu, Peng-long, Zhang, Mei, Chou, Kuo-Chih, Hou, Xin-mei, Yan, Bai-jun
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01.08.2015; Springer Nature B.V; Department of Metalurgical Physical Chemistry, School of Metalurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Clusters; Composites; Corrosion and Coatings; Differential thermal analysis; Electron microscopy; Glass; Materials Science; Metallic Materials; Microscopy; Molten salts; Morphology; Mullite; mullite;nanowhiskers;morphology;silica;molten; Natural Materials; Nucleation; Reaction mechanisms; salt; Silica; Silicon dioxide; Surfaces and Interfaces; Synthesis; Thermal analysis; Thin Films; Tribology; Ultrafines; X-ray diffraction; mullite; reaction mechanisms; molten salt synthesis; morphology; nanowhiskers; silica
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-015-1146-3

Mullite nanowhiskers with Al-rich structure were prepared by molten salt synthesis at 1000°C for 3 h in air using silica, amorphous silica, and ultrafine silica as the silica sources. The phase and morphology of the synthesized products were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy. A thermogravimetric and differential thermal analysis was carried out to determine the reaction mechanism. The results reveal that the silica sources play an important role in determining the morphology of the obtained mullite nanowhiskers. Clusters and disordered arrangements are obtained using common silica and amorphous silica, respectively, whereas the use of ultrafine silica leads to highly ordered mullite nanowhiskers that are 80-120 nm in diameter and 20-30 μm in length. Considering the growth mechanisms, mullite nanowhiskers in the forms of clusters and highly ordered arrangements can be attributed to heterogeneous nucleation, whereas disordered mullite nanowhiskers are obtained by homogenous nucleation.