| dc.description.abstract | In this study, three-dimensional microstructures of copper-tin alloys and its intermetallic compounds were prepared by instant image guided micro-plating.
The electroplating system uses a platinum wire with a wire diameter of 125 μm as an anode, and a copper wire with a diameter of 0.643 mm as a cathode and Cathode and anode distance is 80 μm, which is electroplated in an electroplating bath containing copper sulfate, stannous sulfate, sodium citrate and ascorbic acid
to manufacture three dimensional micro-structure with two metal elements of copper and tin. The goal of this research is to firstly investigate the effect of applying different bias and adding different concentrations of stannous sulfate on the surface morphology, chemical composition, crystal structure and reduction potential of the micro-column in the plating bath, and then seek to find the best electroplating conditions of electroplating micro-columns with two metal elements of copper and tin. Then using these conditions to research the feasibility of making micro-helix, and studying the influence of micro-helix electroplating angle and process parameters on micro-helix size and the variation of wire diameter.
The results showed that When the plating bias is higher and the higher the concentration of stannous sulfate in the electroplating bath, the higher the micro-column tin content. When the bias is set at 3.00 V and the concentration of stannous sulfate is 0.035 M, the copper and tin binary metal micro-column obtained by electroplating have the best surface morphology. After analyzing, its chemical composition is Cu: 88.2 ± 0.6 at.% and Sn: 11.8±0.6 at.%. The crystal structure analysis shows that the crystal structure is Cu6Sn5, Sn coexisting. According to the Scherrer equation, the larger the plating bias, the smaller the grain size.The mechanical properties of the micro-column were measured by a nanoindenter. The hardness was estimated to be 8.10 ± 0.40 GPa and the Young′s modulus was 127.83 ± 5.20 Gpa. The corrosion resistance was measured by electrochemical measurement. The corrosion current (Icorr) was 0.27×10-2 mA/cm2, linear polarization resistance (RLP) is 1435 ohm.
The results of electroplating micro-helix showed that electrochemical deposition angle 30 ° and process parameter 4 is the best electroplating parameter of copper-tin intermetallic compound helix because the diameter of helix wire d1、d2、d3 are the most close, the d2 / d1 ratio is 112 %, the d3 / d1 ratio is 129 %.
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