Aluminum (Al) was successfully bonded with alumina (Al₂O₃) using Ni films of different thicknesses (3, 6, 12 μm) through electroplating and electroless plating processes after annealing at the relatively low melting point of Al. The microstructure, bonding area percentage, shear strength, and thermal conductivity of Al/Al₂O₃ joints were evaluated using scanning electron microscopy, scanning acoustic tomography (SAT), the ISO 13124 test, and the laser flash method respectively. No reaction layer was found at the interface of the Al/Al₂O₃ joint, and the Ni film diffused completely into Al to form an intermetallic compound, Al₃Ni, in the Al foil. The amount and size of the Al₃Ni phase in the Al foil increased gradually with the thickness of the Ni film. The samples with Ni deposited via electroplating had a higher shear stress and bonding area than the samples with Ni deposited via electroless plating. The Al/Al₂O₃ specimen with a 3‐μm‐thick Ni film interlayer deposited using electroplating had the highest shear strength (50.6 MPa), thermal conductivity (39.45 W/mK), and bonding area percentage (~99.97%); therefore, specimens produced under these conditions were considered suitable for use as a substrate in high‐power devices.

中文翻译：

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镍膜中间层厚度对大功率器件中直接键合的铝/氧化铝衬底的影响

在较低的Al熔点下退火后，通过电镀和化学镀工艺，使用不同厚度（3、6、12μm）的Ni膜，成功地将铝（Al）与氧化铝（Al ₂ O ₃）结合。使用扫描电子显微镜，扫描声波断层扫描（SAT），ISO 13124测试和激光闪光法分别评估了Al / Al ₂ O ₃接头的微观结构，结合面积百分比，剪切强度和导热系数。在Al / Al ₂ O ₃接头的界面上未发现反应层，Ni膜完全扩散到Al中形成金属间化合物Al ₃镍，在铝箔中。Al箔中的Al ₃ Ni相的量和大小随着Ni膜的厚度而逐渐增加。通过电镀沉积镍的样品比通过化学沉积镍的样品具有更高的剪切应力和结合面积。通过电镀沉积的具有3μm厚的Ni膜夹层的Al / Al ₂ O ₃试样具有最高的剪切强度（50.6 MPa），导热率（39.45 W / mK）和结合面积百分比（〜99.97％）; 因此，在这些条件下生产的标本被认为适合用作大功率设备的基板。