Effect of seeding on the formation of lanthanum hexaaluminates synthesized through advanced sol gel process

• Published in: Journal of crystal growth 2014-12, Vol.408, p.7-13
• Main Authors: Jana, P., Jayan, P.S., Mandal, S., Biswas, K.
• Format: Article
• Language: English
• Subjects: A1. Crystal morphology; A1. Growth model; A1. X-ray diffraction; A2. Heterogeneous nucleation; B1. Oxides; Cross-disciplinary physics: materials science; rheology; Crystal growth; Drying; Evolution; Exact sciences and technology; Formations; Lanthanum; Materials science; Methods of crystal growth; physics of crystal growth; Nucleation; Physics; Seeds; Sol gel process; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2014.09.015

Advanced sol gel processing was used to synthesize high purity lanthanum hexaaluminate powders. The effect of seeding on the formation of lanthanum hexaaluminate was also studied by seeding the gel. Dry gel was calcined at various temperatures starting from 1100°C to 1600°C for 2h to study the phase evolution. The combine effects of advanced sol gel processing and the presence of seeds promoted the formation of lanthanum hexaaluminate phase at lower temperature than the conventional routes. Lanthanum hexaaluminate phase was detected at 1201°C and 1300°C in seeded and un-seeded gels, respectively. The presence of seed decreases the temperature of formation of lanthanum hexaaluminate by 99°C. Single phase lanthanum hexaaluminate was formed at 1600°C in seeded gel whereas trace of lanthanum monoaluminate phase still present in un-seeded gel even at 1600°C. Lanthanum hexaaluminate crystal nucleates at the conjunction of LaAlO3 and Al2O3 and grows preferentially more along a axis than c axis. [Display omitted] •High purity lanthanum hexaaluminate through advanced sol gel processing from economical precursors.•The effect of seeding on the crystallization and growth of lanthanum hexaaluminate is investigated.•The Presence of seed decreases the temperature of formation of lanthanum hexaaluminate by 99°C i.e., 1201°C.•Seeds also promote the formation of single phase lanthanum hexaaluminate at 1600°C–2h.•The nucleation and growth pattern of lanthanum hexaaluminate are modeled.