Morphology and Structure of Ceramic Thin Films Deposited by Spray Pyrolysis

Abstract

The method of Spray Pyrolysis (SP) was applied to prepare thin films of ceramic or ceramic-metal (cermets) composites based on Cu starting from aqueous solutions of soluble metal salts. Specifically, air pressurized spray pyrolysis was used in order to prepare thin film cermets of Cu-CeO2, Cu-La0.75Sr0.25Cr0.5Mn0.5O3-δ (Cu-LSCM) and the perovskite La0.75Sr0.25MnO3 (LSM) onto dense and porous YSZ substrates. These films have the potential for application in ceramic fuel cells, ceramic membranes, batteries, catalysis and oxygen sensors. Emphasis was given on tuning process parameters such as substrate temperature, solution concentration, nozzle to substrate distance, solution flowrate and deposition time to obtain films with the desired morphology, thickness and crystal structure. Film microstructure was analyzed by scanning electron microscopy (SEM) and it was found that thin defect-free films with excellent adhesion to the substrate could be produced on dense and porous ceramic substrates. X-ray diffraction (XRD) analysis showed that the films were crystalline with only the desired functional phases at relatively low (i.e. 700°C) post-deposition sintering temperatures. It was found that for a given established set of other operational parameters, substrate deposition temperature in conjunction with precursor solution concentration constitute the most significant factors that affect film morphology, adhesion and thickness.