Interfacial reaction and microstructural evolution of Ag-Cu braze on BaCo_0.7Fe_0.2Nb_0.1O_3-δ at high temperature in air

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• 作者：Yuwen Zhang ; ^{springzyw@shu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Lili Zhang ; Wei Guo ; Ting Liu ; Chengzhang Wu ; Weizhong Ding ; Xionggang Lu
• 关键词：Ag-Cu braze ; Mixed ionic-electronic conducting oxides ceramics ; Reactive air brazing ; Wetting ; Interfacial reaction ; Ridge evolution
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：810-819
• 全文大小：6832 K

文摘

Based reactive air brazing technique, interfacial reaction and microstructure formation of Ag-6.6 mol% Cu wetting on BaCo_0.7Fe_0.2Nb_0.1O_3-δ(BCFNO) membrane in air were investigated. The interfacial microstructural analysis revealed that at high temperature Ag-Cu alloy transformed into Ag-Cu-O braze in air and the liquid braze penetrated into BCFNO matrix along the grain boundaries. Cu-O in the liquid braze reacted with BCFNO to form CoCuO₂ and Ba₂Cu₃O_5+x confirmed by XRD. Ridge formed quickly at the triple line as a result of the migration of the interfacial reaction products and in response to the vertical component of force from surface tension. The rapid interfacial reaction and ridging at the spreading front actually stalled the spreading of the liquid braze, rather than a continuous layer of smoother, barrier-free reaction phase forming and driving accompanied spreading. Low macroscopic contact angles between the braze and BCFNO substrate were observed due to the evolution of the ridge composed of the interfacial reaction products near the tripe line.