Sintering Densification and Annealing

Preparation of Solid State Eiectroiytes 17.3.7.1. -Aiumina Ceramic Eiectroiytes 17.3.7.1.3. Sintering (Densification) and Annealing. 

Characterization.— The LSFTO powder was calcined at a series of temperatures (1250, 1300, and 1400°C) in air to investigate phase purity and densification behavior. X-ray diffraction (XRD) powder patterns are shown in Fig. 1. The sample is single phase after heating at 1250°C. At the higher sintering temperatures, the lines become sharper and the density increases. The density measured by the Archimedes method was 90.3% relative to theoretical value after annealing at 1400°C for 10 h. The XRD pattern sintered at 1400°C was completely indexed with a cubic unit cell with lattice parameter a = 3.898(8) A and V= 59.2(6) A3. The weak XRD peaks at 31, 43, 55, and 65° 20 are also from the perovskite phase and arise from a small amount of WL radiation in the incident beam. 

In principle, components can be formed by any standard ceramic fabrication route. The densification step involves a partial melting and a controlled recrystallization, and attention has to be given to sintering/annealing atmospheres to achieve the required stoichiometry. Leads have also been formed by melt-casting. 

---