披覆脈衝直流磁控濺鍍保護層之不鏽鋼高溫氧化行為

High-Temperature Oxidation Behavior of Stainless Steels with Protective Pulsed DC Magnetron Sputtering Coating

楊朋(Peng Yang)

指導教授 ： 宋家驥

國立臺灣大學/工學院/工程科學及海洋工程學研究所/博士(2012年)

https://doi.org/10.6342/NTU.2012.00015

摘要

摻鍶錳酸鑭 (LaxSr1-xMnO3, LSM)為應用於固態氧化物燃料電池(solid oxide fuel cells, SOFCs)連接板披覆層材料，以防止表面氧化及鉻毒化效應。然而在高溫下熱膨脹係數 (thermal expansion coefficient, CTE)之差異性，使LSM保護層產裂間隙而導致鉻揮發。因此本文研究了預氧化對La0.67Sr0.33MnO3保護層與不鏽鋼之微觀結構和電化學性能的影響。研究之四組肥粒鐵系不鏽鋼：Crofer22 APU，Crofer22 H，ss441與G1，分別進行的25和50小時850 oC預氧化程序。經預氧化過程後，使用脈衝直流磁控濺射製程沉積厚度為3~4 μm之LSM薄膜於表面，後續分別用SEM/ EDX和XRD於高溫氧化後保護層試樣的表面型態及和結晶結構進行了觀察。結果顯示材料經預氧化後能有效抑制金屬內部鉻揮發至試樣表面。而Crofer22 APU，Crofer22 H，ss441與G1等四種經預氧化25小時披覆LSM試片，經800 °C其500小時高溫氧化後，面積比電阻 (area specific resistance, ASR)分別為2.24，12.21，2.30和6.77 mΩ•cm2。

關鍵字

摻鍶錳酸鑭 ； 保護層 ； 連接板 ； 固態氧化物燃料電池 ； 預氧化 ； 肥粒鐵系不鏽鋼 ； 脈衝直流磁控濺鍍

並列摘要

LaxSr1-xMnO3 (LSM) is commonly used as a protective layer on the metallic interconnects of solid oxide fuel cells (SOFCs) to prevent surface oxidation and Cr poisoning. However, the different of thermal expansion coefficient (CTE) at elevated temperatures causes the LSM coatings to crack, resulting in Cr evaporation. Therefore, this paper investigates the effects of pre-oxidation on the microstructure and electrical properties of ferritic stainless steels coated with La0.67Sr0.33MnO3. Four ferritic stainless steels were selected for use as interconnect substrates: Crofer22 APU, Crofer22 H, ss441, and G1. The candidate materials were pre-oxidised at 850oC for 25, and 50 hours, respectively. After the pre-oxidation process, the LSM films with a thickness of 3~4 μm were deposited on the surface of samples by using pulsed DC magnetron sputtering. After aging the coated specimens at elevated temperatures, the morphologies and crystalline structures were examined using SEM/EDX and XRD, respectively. The results indicated that the pre-oxidized layer, (Mn, Cr)3O4, could significantly suppress chromium penetration from the interior to the surface of the specimens. Moreover, the area specific resistance (ASR) values for the 25 hours pre-oxidized specimens were 2.24, 12.21, 2.30, and 6.77 mΩ•cm2 for Crofer22APU, Crofer22H, ss441, and G1, respectively, at 800oC for 500 hours in an air atmosphere.

並列關鍵字

LaxSr1-xMnO3 (LSM) ； protective layer ； interconnect ； solid oxide fuel cells (SOFCs) ； pre-oxidation ； ferritic stainless steels ； pulsed DC magnetron

參考文獻

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