Thermal transformation of synthetic euhedral and fibrillar crystals of boehmite into aluminas

• Published in: Materials research bulletin Vol. 31; no. 7; pp. 799 - 807
• Main Authors: De Souza Santos, Helena, Kiyohara, Pedro K., De Souza Santos, Pérsio
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.07.1996; Amsterdam Elsevier Science
• Subjects: A. oxides; B. sol-gel chemistry; C. electron microscopy; C. X-ray diffraction; Cross-disciplinary physics: materials science; rheology; D. phase transitions; Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; B. sol-gel chemistry; D. phase transitions; C. electron microscopy; A. oxides; C. X-ray diffraction; Inorganic compounds; Morphological changes; Synthetic mineral; Phase transformations; Ternary compounds; Crystallization; Binary compounds; Fibrillar structure; Experimental study; Aluminium hydroxides; Crystal growth habit; Crystal growth from solutions; Alumina; Aluminium oxides
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/0025-5408(96)00068-2

Fibrillar pseudoboehmite and euhedral lath-like boehmite aqueous sols were prepared from the reaction of aluminium secondary butoxide and acetic acid in order to have a solid content of 70g/1 of AlOOH. The dried solids were fired from 200 °C to 1500 °C and examined by TEM, SEM, SAED, and XRD to compare formation of aluminas and their crystal morphological changes at the same temperatures. It was observed that the sequence of transformations of fibrillar pseudoboehmite is closer to that for euhedral boehmite than to the “gelatinous boehmite” described in the literature.