热浸镀速率对铜导线表面Pb40Sn60合金镀层组织和力学性能的影响

Effects of hot dip plating rate on microstructure and mechanical properties of Pb40Sn60 alloy coating on copper wire

摘要:

为了改善铜导线的可焊性和耐蚀性，采用热浸镀技术在铜导线表面制备了Pb40Sn60合金镀层，分析了不同热浸镀速率下Pb40Sn60 合金镀层的微观组织、相成分及力学性能。结果表明，Pb40Sn60合金镀层由α和β两相组成，且α相比β相的相对量较多。随着热浸镀速率的增大，铜导线热浸镀Pb40Sn60合金镀层的厚度增厚，其结晶形态由片层状和等轴状逐渐转变为树枝状。热浸镀过程对铜导线会产生消除加工强化的作用，随着热浸镀速率的减小，热浸镀Pb40Sn60合金镀层铜导线的强度显著降低，延伸率变化较小，铜导线基体的硬度呈略微降低的趋势，镀层硬度亦呈减小的趋势。提高热浸镀速率，有利于镀层的结晶与生长；反之，降低热浸镀速率，有利于消除铜导线基体的加工硬化。

Abstract:

Hot dip plating is used to prepare Pb40Sn60 alloy coatings on copper wires to improve the properties of weldability and corrosion resistance, the microstructure and phase composition of Pb40Sn60 alloy coating under different hot dip plating rates were examined by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). and the mechanical properties of Cu wires with Pb40Sn60 alloy coating under different hot dip plating rates were investigated by the tensile test. The results show that the Pb40Sn60 alloy coatings are all composed of α phase and β phase, and the relative amount of α phase is more than β phase. With the increase of hot dip plating rate, the thickness of Pb40Sn60 alloy coating on copper wire are thickened, and the crystal morphology is change from lamellar or equiaxial to dendritic. The work hardening of copper wires can be eliminated during the hot dip plating process. With the decrease of hot dip plating rate, the strength of copper wires with Pb40Sn60 alloy coating is decrease significantly, and the elongation is not obvious change, the hardness of copper wires substrate shows a slightly decreasing trend, and the hardness of coating shows a slightly decreasing trend. There is beneficial to the crystallization and growth of the coating by increasing the rate of hot dip plating, on the contrary, there is beneficial to remove the work hardening of copper wire substrate by reducing the rate of hot dip plating.