目的 开发新型的置换化学镀方法，制备微米尺寸的覆银铜粉，进一步开展覆银铜粉在导电胶中的应用研究。方法 通过改变置换反应的时间，分别得到10~60 ℃内银的覆载量的变化曲线，通过拟合表面 反应动力学方程，得到该反应在不同温度下的速率常数。对所获得的材料开展XRD、SEM等的表征，并 利用该材料开展了导电胶的应用研究。结果 通过拟合Arrhenius方程，确定了该置换反应的活化能为 4.1×10⁴ J/mol。利用形貌表征和20%的HNO3溶液浸泡处理，结果证实，经过3 h的置换反应，铜粉可以完全被银层覆盖。通过热重分析可知，覆银层可以显著提高材料的抗氧化性，且随着置换反应温度的提高，抗氧化性也进一步增强。将40 ℃条件下制备的覆银铜粉与环氧树脂制成55%的导电胶，测试了样品的热稳定性，结果表明，经过40 h的烘烤，电阻稳定在0.8 Ω以内，随后电阻有小幅上升，但在65 h以后，电阻稳定在2 Ω以内，不再发生变化。结论 利用置换化学镀获得的覆银铜粉具有良好的导电性和抗氧化能力。该方法简单可靠，具有较高的产业化前景，有利于对大规模工业化生产的指导。

The micrometer-scale silver-coated copper powder was prepared by a novel replacement chemical plating. Compared with the traditional chemical plating, further study on the application of silver coated copper powder in conductive adhesive. By changing the plating solution temperature, a series of silver loading curves from 10 ℃ to 60 ℃ were obtained respectively, from which a series of the rate constants of the replacement reaction at different temperatures were deduced with a theoretical fitting to the surface reaction kinetics. By fitting the Arrhenius equation, the activation energy of replacement reaction was achieved to be 4.1×104 J/mol. The morphology and crystal structure of the silver-coated copper powder were investigated by SEM and XRD, and the surface coverage of the prepared sample was tested by an immersion in a 20% HNO3 solution. It demonstrated that the copper powder can be completely covered by silver while the replacement reaction time is longer than 3 h. The thermogravimetric analysis proved that the silver coating can significantly improve the oxidation resistance of the material. The silver-coated copper powder and epoxy resin prepared at 40 ℃ are used to make 55% conductive adhesive. The results showed that the sample resistance keeps stable at a resistance of less than 0.8 Ω within 40 h baking, although it has a slight increase hereafter due to the thermal diffusion of the copper atoms to the particle surface. The results provided in the present manuscript show great potential in the practical application.