雙自熔旋轉電極雙層金屬粉末製備金屬板孔隙率改善之研究

Study of High Temperature Behavior of Metal Plate prepared by dual layer powder

程羿穆(Yi-Mu Cheng)

指導教授 ： 連雙喜

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.11009

摘要

固態氧化物燃料電池(SOFC)由於有高的轉換效率、環境親和性，為近年來受到重視的替代性能源之一；然而固態氧化物燃料電池(SOFC)其關鍵零組件連接板在成本及高溫性質方面，仍有待改進，方能具有市場上的競爭力。其中關鍵零組件之一 (SOFC)的金屬連接板材料需要具備匹配電解質的熱膨脹係數、良好的導電性質和抗高溫氧化性質與低廉的成本方能使SOFC未來成為普及化的替代能源。
金屬連接板製程採用傳統熔煉、軋壓，再加工…等的製程，其成本較高，材料的浪費也相對較多，且有雜質汙染情形，影響了連接板導電性及高溫抗氧化能力，因此本實驗採用粉末冶金法製造連接板，粉末冶金法可直接成形並降低製造費用。但二元鐵鉻合金的粉末冶金法樣品孔隙率偏高，與氧氣接觸面積大，氧氣可以輕易進入內部造成抗氧化性質變差。因此亦嘗試電漿噴塗製程製作，其便利、快速製造且樣品孔隙率相對較低，可改善高溫氧化及高溫電阻性質。
鐵鉻基合金為目前使用較多的連接板材料，其用途普遍取得容易且普遍成本相對便宜，但高溫氧化膜增厚亦增高電阻性質，傳統噴霧氣化法製粉則有夾渣汙染情形，為改善上述缺點本研究以旋轉電極法製備內層為SS440、外層為Ni基材之雙層金屬粉末，粉末高溫氧化實驗結果顯示雙層金屬粉末高溫抗氧化能力確有提升。本論文分別以傳統粉末冶金法與電漿噴塗法，製作固態氧化物燃料電池(SOFC)的金屬連結板。所得樣品進行150小時不連續高溫氧化實驗、高溫電阻實驗、金相成份分析等後續性質檢定。

關鍵字

燃料電池 ； 金屬連接板 ； 旋轉電極 ； 高溫氧化 ； 雙層金屬粉末

並列摘要

Solid oxide fuel cell is one of the most important fuel cells for alternative green energy due to its high efficiency of electrical energy conversion, low noise and environmental friendliness. Wherein SOFC metallic interconnector is an critical part in relation to life time, conductivity, high temperature oxidation resistance and cost. Fe-Cr alloy has been considered as a good candidate for making metallic interconnector due to its low cost and fare properties. Nevertheless Fe-Cr alloy still has some inadequacies to be improved, such as low resistance to oxidative deterioration due to volatile of oxide layer at high temperature. Although Fe-Cr alloy interconnector made from powder metallurgy with mixed metal powder(Fe-20Cr) could save manufacturing cost and materials loss, the sintered part of interconnectors contain pores that will decrease oxidation resistance.
In this study, a special technique has been applied to improve the porosity and oxidation resistance of powder metallurgy made sample by plasma spray with dual layer hybrid powder. Dual layer hybrid powder with inner layer of stainless steel 440 and the outer layer of nickel was prepared with double consumable rotating electrodes powder making method. The two layers of powder were then sprayed on the surface of 304 stainless steel and 1025 carbon steel substrates with atmosphere plasma spray equipment. The oxidation resistance of normal sintered power metallurgy and plasma spray made samples were evaluated for their oxidation weight gain at 800℃ discontinuously for a total of 150 hours. The results showed that powder metallurgy made specimen had upper 80% relative density, but the fine mixed metal powder(Fe-20Cr) added did not be sintered as uniform alloy between dual layer powders that deteriorated oxidation resistance. In addition, the plasma spray samples had superior oxidation resistance than the conventional powder metallurgy made parts with the same double layer powders.

並列關鍵字

SOFC ； metallic interconnect ； rotating electrode process(REP) ； high temperature oxidation

參考文獻

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