The Preparation And Performance Study Of NiMn₂O₄ Coating On The Rare Earth Modified Fe-Cr Ferritic Alloy Interconnection For SOFC

With the progress of solid oxide fuel cell(SOFC) technology,it’s operating temperature have gradually reduced from 1000℃to 600~800℃,which make the alloy connecting material instead of traditional ceramic material becomes possible.However, the oxide layer of ally connector grow rapidly at high temperature oxidizing atmosphere and Cr volatilizing produced cathode poisoning problems make the performance of cell stack greatly reduced. Currently,the primarily solution is develop a alloy surface protection layer.In this paper, the low cost of sol gel method(sol-gel) is used to prepare NiMn2O4 spinel coating on the surface of a new rare earth modified Fe-Cr ferritic alloy connector.The study is developed in three aspect: First, use sol-gel method to make the NiMn2O4 spinel powder material and optimize the related experimental parameters, in order to prepare for subsequent coating.Second, study the high temperature oxidation behavior of the rare earth modified Fe-Cr ferritic alloys, analysis the feasibility of this alloy as SOFC connection material and determine the suitable preoxidation process for matrix.Third, Use the sol-gel pulling technique to coated Ni Mn2O4 material on the surface of rare earth modified Fe-Cr ferritic alloy, characterized the coating structure, high temperature oxidation and conductive properties.The main results were followed as:1.By optimizing the experimental process parameters(such as ligand types, PH, stirring time, stirring speed, heating temperature, drying temperature and time, sintering temperature, etc.), the low cost of sol-gel method can be used to synthetic a good crystallinity, particle size uniformly distributed NiMn2O4 spinel materials;2.When the alloy oxidized at 650℃for 48 h, a thin layer of oxide substance Cr2O3 appears on the sample surface, oxide layer appears and the growth not obvious,so it can be used as a substrate pre-oxidation temperature,when oxide in air at a working temperature 800℃ in the low-temperatured solid oxide fuel cell for 0~168h, the oxidation rate is only 9.63×10-15 g2·cm-4·s-1, so it is an appropriate connecting alternative materials for SOFC;3.The sol-gel method can be used to prepare NiMn2O4 coating that have an compact structure and well combined with matrix,on the surface of rare earth modified Fe-Cr alloy. Compared with the unapplying coating alloy, Ni Mn2O4 coating on the applyed ally oxided at 800℃in air for168 h, their oxidation rate is only 3.05×10-15g2cm-4s-1, coating protection alloy also has lower and stable surface resistivity for a long time. That means NiMn2O4 spinel is a suitable coating material for the rare earth modified Fe-Cr alloy connecting...