喷涂条件与热处理对La_(0.5)Sr_(0.5)CoO_(3-δ)涂层含氧量的影响  

Effects of Spray Condition and Annealing Treatment on Oxygen Contents of Thermally Sprayed La_(0.5)Sr_(0.5)CoO_(3-δ) Coatings

作　　者：高敏[1] 李长久[1] 李成新[1] 范圣强[1] 

机构地区：[1]西安交通大学材料科学与工程学院,西安710049

出　　处：《西安交通大学学报》2010年第3期115-119,共5页Journal of Xi'an Jiaotong University

基　　金：国家高技术研究发展计划资助项目(2007AA05Z135)

摘　　要：采用火焰喷涂与等离子喷涂方法制备了La0.5Sr0.5CoO3-δ涂层,并在1 000℃热处理3 h,用碘滴定法测定了涂层热处理前、后的含氧量,研究了喷涂方法、制备条件及热处理对该阴极涂层含氧量的影响.结果表明:受喷涂过程中高温加热过程的影响,原始涂层存在大量的氧空位,含氧量较低;等离子喷涂层的氧损失量显著高于火焰喷涂层.经热处理后,缺失的氧得到一定程度的回复,涂层含氧量增加.较高的氧空位浓度使喷涂态La0.5Sr0.5CoO3-δ涂层发生晶格畸变,从而使其发生从钙钛矿结构的立方晶向四方晶的转变,而热处理引起的氧回复则可使结构回复至立方晶.La1-xSrxCoO3-δ（LSCO） is a promising cathode material for solid oxide fuel cells（SOFCs）.The properties of the LSCO cathode are significantly influenced by its oxygen content.In this paper,La0.5Sr0.5CoO3-δ coatings are prepared by both flame spraying and plasma spraying.Annealing treatment of the LSCO coatings is performed at 1 000 ℃ for 3 hours.Oxygen contents of different samples are investigated by iodine titration.The effects of spray condition and annealing treatment on the oxygen content of the La0.5Sr0.5CoO3-δ are investigated.The results show that oxygen contents in the as-sprayed coatings get significantly lower than that in the starting powder owing to heating to a high temperature of spray particles by high temperature flame.The escaped oxygen of plasma-sprayed La0.5Sr0.5CoO3-δ is more than that of flame-sprayed one.The oxygen content significantly increases after annealing treatment.It is clear that the deficit oxygen can be recovered through annealing treatment.The lattice distortion occurs in the thermally sprayed coatings due to large concentration of oxygen vacancies,which induces tetragonal phase formation.It is also found that recovery of oxygen through annealing treatment leads to a recovery phase transformation from tetragonal phase to perovskite cubic phase.

关 键 词：La0.5Sr0.5CoO3-δ 等离子喷涂 火焰喷涂 含氧量 碘滴定法 

分 类 号：O655.23[理学—分析化学]