采用溅射Al和Al-Ni薄膜作为钎料的方法,研究了溅射Al对Si₃N₄的润湿作用,实现了铝基薄膜钎料对Si₃N₄陶瓷的直接钎焊。结果表明,Al直接溅射在Si₃N₄表面所获得的各钎焊接头钎缝致密饱满,与陶瓷形成无反应过渡层的良好冶金结合,纯Al钎焊接头的剪切强度为106 MPa,Al-1.0%Ni亚共晶钎焊接头的强度提高到148 MPa,Al-3.0%Ni接头的强度因钎缝形成共晶组织而略有降低,为132 MPa,这些接头的剪切断裂均产生于钎缝之中。采用首先溅射Ni薄膜作为底层的Al-1.0%Ni薄膜钎料进行了对比,这种钎料得到的钎焊接头断裂产生于钎缝与陶瓷的界面,强度也仅为81 MPa。这表明,高能量溅射Al粒子直接撞击对Si₃N₄具有“润湿”作用,使得Al和Al-Ni合金薄膜熔化后即可实现对Si₃N₄的钎焊。

In the present technology, the brazing of Si₃N₄ needs a reactive transition layers to resolve the non-wetting problem of usual metal fillers. Aluminum could wet Si₃N₄ without reaction but the brazing is very difficult due to wetting temperature above 1000 ℃. In this work, the wetting effect of sputtered Al films on Si₃N₄ and its physics essence were revealed. Based on this, the brazing of Si₃N₄ ceramic with Al or Al-Ni film fillers was realized near their melting temperature. The results showed that the seams of brazing joints with direct sputtered Al on Si₃N₄ film were well-stacked and less defects, and well metallurgically bonded to ceramic without reactive transition layers. The shear strength of pure Al/Si₃N₄ joint reached 106 MPa. The strength increased to 148 MPa with adding 1.0%Ni into film filler due hypoeutectic structure in the seam. With further increasing Ni content to 3.0%, the eutectic structure of the seam slightly decreased the strength of joint to 132 MPa. These joints above all fractured in joint seams. Moreover, the Al-1.0%Ni film filler first sputtered Ni layer was compared. Its brazing joint fractured at the interface between seam and ceramic and the shear strength decreased to only 81 MPa. This comparsion revealed the "wetting" effect of the bombardment of energetic sputtered Al particles. This effect still existed after filler melting and the direct brazing of Si₃N₄ ceramic without reactive transition layers was realized.