![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
Phase evolution behaviour of lanthanum strontium manganite (LSM) and nickel oxide-yttria stabilized zirconia (NiO-YSZ) composite from the respective oven dried fuel – metal nitrate gels (citrate-metal nitrate for LSM and glycine-metal nitrate for NiO-YSZ) was studied using TG-DTA, XRD and FTIR. The TG-DTA revealed sharp exotherms around 200° and 221°C attributed to the setting in of combustion of gels of LSM and NiO-YSZ respectively. The XRD results indicated formation of nanocrystalline LSM and NiO-YSZ phases above 200° and 221°C respectively. The FTIR spectra of LSM and NiO-YSZ gels heated above 200° and 221°C exhibited characteristic absorption bands corresponding to metal-oxygen vibrations in LSM and NiO-YSZ indicating formation of the respective compounds. However, chemical and phase pure LSM and NiO formed above 700°C indicate the minimum calcination temperature to be used in the processing. The role of calcination treatment on powder characteristics in the temperature range of 700° to 1350°C was studied. With increasing calcination temperature of the as-formed powders, the characteristics such as crystallite size, median particle size (D50), green density of the compacts increased while specific surface area decreased. Typical sintering studies at 1400° and 1450°C revealed that sinterability and per cent linear shrinkage decreased with increasing calcination temperature. However, the required amount of porosity for SOFC application could be obtained with incorporation of a pore former in case of LSM and varying the sintering time in case of NiO-YSZ composite.