BaCe_(0.7)Zr_(0.1)Y_(0.1)Yb_(0.1)O_(3-δ)质子导电陶瓷与不锈钢的空气反应钎焊分析

Reactive air brazing of BaCe_(0.7)Zr_(0.1)Y_(0.1)Yb_(0.1)O_(3-δ) proton conductive ceramic and stainless steel

针对质子陶瓷燃料电池堆中BaCe_(0.7)Zr_(0.1)Y_(0.1)Yb_(0.1)O_(3-δ)(BCZYYb)质子导电陶瓷与Crofer22APU不锈钢的连接难题展开研究,探究了Ag-CuO钎料在BCZYYb陶瓷表面的润湿性能,分析了CuO与陶瓷反应对钎料润湿的驱动作用.研究了Ag-CuO钎料的空气反应钎焊工艺,在1010℃/20 min工艺条件下实现了质子导电陶瓷与不锈钢的无缺陷连接,分析了接头两侧界面连接特性以及接头元素分布规律.结果表明,CuO与陶瓷基体中BaO的反应促进了钎料润湿,钎料扩散进入陶瓷基体形成了较厚的渗透层,CuO与不锈钢保护层(Mn,Co)_(3)O_(4)的反应促进了保护层致密化,保护层在连接过程对不锈钢基体起到了良好的保护作用.系统分析了CuO含量对接头组织与性能的影响规律,采用Ag-CuO(2%,质量分数)钎料获得了最高接头剪切强度(21.6 MPa),综合评定了钎缝两侧界面反应对接头性能的影响.

In this study,the joining problem between the BaCe_(0.7)Zr_(0.1)Y_(0.1)Yb_(0.1)O_(3-δ)(BCZYYb)ceramic and Crofer 22 APU stainless steel in the protonic ceramic fuel cell stack was studied.The wettability of Ag-CuO braze on the surface of BCZYYb ceramic was explored.And the driving effect of the reactions between CuO and ceramic matrix on braze wetting was analyzed.The reactive air brazing process of Ag-CuO braze was studied,and the BCZYYb ceramic was soundly brazed to the stainless steel at 1010℃ for 20 min.The interfacial joining properties on both sides and the element distribution of joints were analyzed.It is showed that the wetting of Ag-CuO braze was promoted by the reactions between the CuO and BaO in the ceramic matrix.The braze could diffuse into the ceramic matrix,forming a thick fusion layer.The densification of the(Mn,Co)_(3)O_(4) protective layer on the stainless steel could be densified by its reactions with the CuO from the braze,which played a key role in protecting the stainless steel from oxidization during reactive air brazing.Effects of CuO content on the microstructure and properties of joints were analyzed systematically.The highest shear strength of joints(21.6 MPa)was obtained by using Ag-2wt%CuO braze.