高纯氧化铝与金属铌的活性钎焊

Active brazing of high purity alumina to niobium metal

为了确定高纯氧化铝陶瓷与金属Nb的直接钎焊工艺参数，采用AgCuTi活性钎料，研究了钎焊温度和钎料中的钛含量对接头组成、界面反应以及接头剪切强度的影响。钎焊温度在825～900℃范围变化时，对接头强度的影响不明显，但温度超过900℃强度降低。钎料中钛的质量分数为1％和2％时，接头的强度基本相同；含量为3％时，剪切强度明显降低。当钛的质量分数为2％，钎焊温度为850℃，保温时间为20min时，接头剪切强度接近100MPa。接头陶瓷一侧界面反应产物主要为Cu3Ti3O和Ti的氧化物，较高温度时反应层中生成的过多Ti2O可能是导致接头强度显著降低的一个重要因素。

High purity alumina ceramics were brazed to niobium metal to analyze the effects of brazing temperatures and Ti content in the active AgCuTi alloy filler on the joint microstructure, interracial reactions and shear strengths. The results show that brazing temperatures of 825 - 900 ℃ do not significantly affect the joint strength, hut that the joint strength decreases at temperatures higher than 900 ℃. The joint strength slightly decreases for Ti mass fractions of 1% - 2%, while significantly decreasing for Ti mass fractions above 3%. The maximum joint shear strength reaches 100 MPa at 850 ℃ and a Ti mass fraction of 2% with a keeping time of 20 min. The interracial reaction products adjacent to the alumina are mainly Cu3Ti3O and Ti oxide, in which the redundant Ti2O produced in the reaction layer at higher temperatures might be a key factor in reducing the joint strength.