Effects of ultrasonic on microstructure and mechanical properties of electroforming copper layer

To improve the mechanical properties of electroforming micro components, the electroformed copper layer with different microstructures was prepared by introducing ultrasonic-assisted technique and changing the process parameters during electroforming. The microstructure of the electroformed copper layer was observed by optical microscope (OM) and scanning electron microscope (SEM). The preferred orientations of the layer were characterized by X-ray diffraction (XRD). The mechanical properties were evaluated with a Vicker's hardness tester and a tensile tester. The results show that the electroformed copper layer is textured with Cu-(220) both in ultrasonic and non-ultrasonic conditions, and the copper layer's preferred orientation electroformed in ultrasonic condition is stronger than that of in normal condition. The analysis of mechanical properties shows that the tensile strength and microhardness of the copper layer both raise 30% and the microstructure is fine columnar crystals when electroformed under the condition of ultrasonic agitation. When the concentration of Cl^- in solution is 60 mg/L, the grain of the copper layer distributes more uniformly, the tensile strength and the ductility of it are both higher than those in other Cl^- concentrations. Meanwhile, the integral mechanical properties of the electroformed copper electroformed in ultrasonic condition are significantly improved in comparison with the pure copper deposit.