论文部分内容阅读
研究了240℃,温度梯度为1045℃/cm的热迁移条件下Cu含量对Ni/Sn-xCu/Ni(x=0.3、0.7、1.5,质量分数,%)微焊点钎焊界面反应的影响。结果表明,在热迁移过程中微焊点发生了界面金属间化合物(IMC)的非对称生长和转变以及Ni基体的非对称溶解。在Ni/Sn-0.3Cu/Ni微焊点中,虽然界面IMC类型始终为初始的(Ni,Cu)3Sn4,但出现冷端界面IMC厚度明显大于热端的非对称生长现象。在Ni/Sn-0.7Cu/Ni和Ni/Sn-1.5Cu/Ni微焊点中,界面IMC类型逐渐由初始的(Cu,Ni)6Sn5转变为(Ni,Cu)3Sn4,且出现冷端滞后于热端的非对称转变现象;Ni/Sn-1.5Cu/Ni微焊点冷、热端发生IMC转变的时间均滞后于Ni/Sn-0.7Cu/Ni微焊点。通过分析微焊点冷、热端界面IMC生长所需Cu和Ni原子通量,确定Cu和Ni的热迁移方向均由热端指向冷端。微焊点中的Cu含量显著影响主热迁移元素的种类,进而影响冷、热端界面IMC的生长和转变规律。此外,热迁移促进了热端Ni原子向钎料中的扩散,加速了热端Ni基体的溶解,溶解到钎料中的Ni原子大部分迁移到冷端并参与界面反应。相反,热迁移显著抑制了冷端Ni原子的扩散,因此冷端Ni基体几乎不溶解。
The effect of Cu content on Ni / Sn-xCu / Ni (x = 0.3,0.7,1.5 mass%,%) micro-brazing interface reaction under 240 ℃ and temperature gradient of 1045 ℃ / cm was studied. . The results show that the asymmetric growth and transformation of intermetallic compounds (IMC) and the asymmetric dissolution of Ni matrix occur in the micro-solder joints during the heat transfer process. In the Ni / Sn-0.3Cu / Ni micro-spot, although the type of the interface IMC is always the initial (Ni, Cu) 3Sn4, the thickness of the IMC at the cold junction is significantly larger than the asymmetric growth at the hot end. In Ni / Sn-0.7Cu / Ni and Ni / Sn-1.5Cu / Ni micro-joints, the interfacial IMC type gradually changes from the initial (Cu, Ni) 6Sn5 to (Ni, Cu) 3Sn4, The asymmetric transition at the hot end. The time of IMC transition at the cold / hot side of the Ni / Sn-1.5Cu / Ni micro-junction lagged behind the Ni / Sn-0.7Cu / Ni micro-spot. By analyzing the flux of Cu and Ni atoms needed for the growth of IMC at the cold and hot end of micro-solder joints, the hot migration directions of Cu and Ni are determined to be from the hot end to the cold end. The Cu content in the micro-solder joints significantly affects the types of main heat-transfer elements, which in turn affects the growth and transformation of the IMC at the cold and hot-end interfaces. In addition, the thermal migration promoted the diffusion of Ni atom from the hot end into the solder and accelerated the dissolution of the Ni matrix on the hot end. Most of the Ni atoms dissolved in the solder migrated to the cold end and participated in the interfacial reaction. In contrast, the heat transfer significantly inhibits the diffusion of cold-end Ni atoms, so the cold-end Ni matrix hardly dissolves.