화학공학소재연구정보센터
Materials Chemistry and Physics, Vol.228, 254-262, 2019
Sintering and ionic conduction of neodymium-bearing fluorobritholites
The present work describes the sintering and ionic conductivity of rare-earth-based fluorobritholite (Sr8La2.xNdx(PO4)(4)(SiO4)(2)F-2 with 0 <= x <= 2). The materials were prepared via conventional solid state reactions. The analysis and characterization of the synthesized powders were carried out using several techniques. The samples' ionic conductivity sigma was measured via a complex impedance spectroscopy. The results showed that the substitution of lanthanum and/or neodymium by strontium and silicates by phosphorus in fluorapatite has been established and well-crystallized single-phase apatites were consequently obtained as a result. The neodymium lanthanum substitution was total according to the small dimensional differences between the two cations. Next, the powders were after that compacted into pellets and then pressurelessly sintered at a 1250-1450 degrees C temperature range. The relative densities of the sintered bodies were found to depend on sintering temperature as well as on Nd content. The 90% relative density was obtained with x = 2 sample sintered at 1250 degrees C. The microstructures of the densest bodies were characterized by a closed porosity. The measured ionic conductivity a of the samples was found to depend simultaneously on both the Nd content and the heating temperatures, while the maximum value of 2.73 10(-6) S cm(-1) was obtained at 780 degrees C for x = 2. A correlation between material structures and densification ratios with the ionic conductivity a was detailed.