本文關鍵詞： 固體氧化物燃料電池 封接材料 玻璃網絡結構 化學穩(wěn)定性　出處：《福州大學》2014年碩士論文　論文類型：學位論文

【摘要】：固體氧化物燃料電池(SOFC)是一種直接將儲存在燃料和氧化劑中的化學能高效、環(huán)境友好地轉化為電能的全固態(tài)化學發(fā)電裝置。由于其具備較高的能量密度,燃料適應性強能量轉換效率高、零污染、全固態(tài)模塊化組裝等優(yōu)點而在能源領域備受矚目。作為SOFC的關鍵技術之一,可靠的封接技術將對SOFC的發(fā)展具有重大的推進意義。SOFC的運行溫度較高,因此封接材料必須在高溫下保持各方面性能的穩(wěn)定性,包括熱性能、氣密性、化學穩(wěn)定性、電導率等。在燃料電池實際應用中已經發(fā)現,封接材料容易與金屬連接體發(fā)生氧化還原反應,生成高膨脹系數的鉻酸鹽,導致界面開裂,影響封接性能尤其是高溫循環(huán)穩(wěn)定性。本課題在分析了封接材料的發(fā)展狀況以及目前所存在問題的基礎上,針對SrO-CaO-SiO2-B2O3體系的基礎硼硅玻璃進行系統的探索和研究。首先,本論文研究了Al2O3含量對硼硅玻璃體系的結構與性能的影響。作為網絡中性體的Al2O3在含量低于8 mole%時以網絡形成體的形式存在于玻璃網絡結構中,起到補網的作用。隨著Al2O3含量的提高,玻璃的析晶趨勢逐漸減弱。樣品glass#6Al2O3 (含6 mole% Al2O3)和Cr2O3粉末在700℃下反應生成的Cr6+含量最高。樣品glass#4Al2O3的不銹鋼涂層在700℃下保溫100小時后界面完整,顯示出良好的封接性能。其次,研究了Zr02對硼硅封接材料的結構與封接性能,尤其是高溫化學穩(wěn)定性的影響。析晶溫度的變化趨勢表明,Zr02的添加提高了析晶溫度,抑制玻璃的析晶過程。隨著Zr02含量的增加,玻璃的軟化溫度和玻璃轉變點逐漸增高,表明ZrOz的添加使得玻璃網絡結構更加致密。在700℃下進行的模擬界面反應,由于ZrO2對玻璃網絡結構的增強作用,產物中Cr6+的相對含量(即反應率)逐漸降低；而在750℃和800℃下,由于玻璃析晶的作用,界面反應率呈現出與700℃下相反的變化趨勢。封接界面的微觀分析表明,添加4 mole%和6 mole% ZrO2的玻璃具有良好的封接性能。最后,探索了ZnO對硼硅封接材料的結構與封接性能,尤其是在燃料電池工作環(huán)境中的熱穩(wěn)定性的影響規(guī)律。結果表明,ZnO的添加降低了封接材料玻璃轉變點和軟化溫度,促進了玻璃的析晶。同時,ZnO含量的進一步增加(16 mole% ZnO)導致玻璃失重率提高,穩(wěn)定性下降。相關結果為封接材料的設計提供思路。
[Abstract]:Solid oxide fuel cell (SOFC) is a kind of chemical energy which is stored directly in fuel and oxidant. Environmentally friendly all-solid-state chemical power generation device. Because of its high energy density, fuel adaptability, high energy conversion efficiency, zero pollution. As one of the key technologies of SOFC, all solid-state modular assembly has attracted much attention in the field of energy. Reliable sealing technology will be of great significance to the development of SOFC. The operating temperature of SOFC is high. Therefore, the sealing materials must maintain the stability of all aspects of performance, including thermal performance at high temperature. Gas tightness, chemical stability, conductivity and so on. In the practical application of fuel cell, it has been found that the sealing material is easy to redox with metal connectors, forming chromate with high expansion coefficient, which leads to interface cracking. This paper analyzes the development of sealing materials and the existing problems. The basic borosilicate glass of SrO-CaO-SiO2-B2O3 system is systematically explored and studied. First of all. In this paper, the effect of Al2O3 content on the structure and properties of borosilicate glass system has been studied. The content of Al2O3, as a network neutral, is lower than 8%. Mole% exists in the glass network structure in the form of network formation. Play the role of net. With the increase of Al2O3 content. The crystallization trend of the glass gradually decreased. Sample glass#6Al2O3 (containing 6 mol% Al _ 2O _ 3). The highest content of Cr6 was obtained by reaction with Cr2O3 powder at 700 鈩，

本文編號：1474582