Huang Liang-Wei, Shiue Ren-Kae, Liu Chien-Kuo, Cheng Yung-Neng, Lee Ruey-Yi, Tsay Leu-Wen
Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan.
Nuclear Fuels and Materials Division, Institute of Nuclear Energy Research, Taoyuan 32546, Taiwan.
Materials (Basel). 2022 Jan 26;15(3):939. doi: 10.3390/ma15030939.
The study focused on dissimilar brazing of metallized YSZ (Yttria-Stabilized Zirconia) and Crofer alloy using BAg-8 (72Ag-28Cu, wt%) filler foil. The YSZ substrate was metallized by sequentially sputtering Ti (0.5/1 μm), Cu (1/3 μm), and Ag (1.5/5 μm) layers, and the Crofer substrate was coated with Ag layers with a thickness of 1.5 and 5 μm, respectively. The BAg-8 filler demonstrated excellent wettability on both metallized YSZ and Crofer substrates. The brazed joint primarily consisted of Ag-Cu eutectic. The metallized Ti layer dissolved into the braze melt, and the Ti preferentially reacted with YSZ and Fe from the Crofer substrate. The globular FeTi intermetallic compound was observed on the YSZ side of the joint. The interfacial reaction of Ti was increased when the thickness of the metallized Ti layer was increased from 0.5 to 1 μm. Both brazed joints were crack free, and no pressure drop was detected after testing at room temperature for 24 h. In the YSZ/Ti(0.5μ)/Cu(1μ)/Ag(1.5μ)/BAg-8(50μ)/Ag(1.5μ)/Crofer joint tested at 600 °C, the pressure of helium decreased from 2.01 to 1.91 psig. In contrast, the helium pressure of the YSZ/Ti(1μ)/Cu(3μ)/Ag(5μ)/BAg-8(50μ)/Ag(5μ)/Crofer joint slightly decreased from 2.02 to 1.98 psig during the cooling cycle of the test. The greater interfacial reaction between the metallized YSZ and BAg-8 filler due to the thicker metallized Ti layer on the YSZ substrate was responsible for the improved gas-tight performance of the joint.
该研究聚焦于使用BAg-8（72Ag-28Cu，重量百分比）填充箔对金属化氧化钇稳定氧化锆（YSZ）和克罗费尔合金进行异种钎焊。通过依次溅射钛（0.5/1μm）、铜（1/3μm）和银（1.5/5μm）层对YSZ基板进行金属化处理，而克罗费尔基板分别涂覆有厚度为1.5μm和5μm的银层。BAg-8填充材料在金属化的YSZ和克罗费尔基板上均表现出优异的润湿性。钎焊接头主要由银铜共晶组成。金属化钛层溶解到钎焊熔池中，钛优先与YSZ以及克罗费尔基板中的铁发生反应。在接头的YSZ一侧观察到球状的FeTi金属间化合物。当金属化钛层的厚度从0.5μm增加到1μm时，钛的界面反应增强。两个钎焊接头均无裂纹，在室温下测试24小时后未检测到压降。在600℃下测试的YSZ/Ti(0.5μ)/Cu(1μ)/Ag(1.5μ)/BAg-8(50μ)/Ag(1.5μ)/克罗费尔接头中，氦气压力从2.01 psig降至1.91 psig。相比之下，在测试的冷却循环过程中，YSZ/Ti(1μ)/Cu(3μ)/Ag(5μ)/BAg-8(50μ)/Ag(5μ)/克罗费尔接头的氦气压力从2.02 psig略微降至1.98 psig。由于YSZ基板上金属化钛层较厚，使得金属化YSZ与BAg-8填充材料之间的界面反应更大，这是接头气密性能提高的原因。
