Processing Effects on Phase and Microstructure of Plasma Sprayed Strontium doped Lanthanum Manganite

Strontium doped Lanthanum Manganite (LSM) oxide materials have high electrical conductivity, good electrochemical performances and stability with YSZ electrolyte at high temperature, so it is widely used in solid oxide fuel cells (SOFCs). In this paper, processing effects on in-flight particle state, microstructure and phase formation of LSM oxide coatings were studied. A DPV-2000 system of Tecnar Automation Ltd. was applied to measure in-flight particle temperature T and velocity V that were varied by changing spray conditions, such plasma gas flow, current and spray distance et al. In situ coating property sensor (ICP) was applied during coating deposition to measure residual stresses and elastic moduli in the coating, combined with other characterization tools for electrical property and microstructure analysis and phase formation. It turned out that phase formation of the coating was more sensitive to hydrogen percentage in plasma gas than temperature. High temperature only resulted in distorted phase in the coating, but high hydrogen percentage can cause decomposition of the LSM coating.