CuNi_(44)合金电沉积过程的研究

Study on electrodeposition of CuNi_(44) alloy

采用循环伏安、极化曲线、恒电位阶跃等电化学测试方法研究了铜镍合金的电沉积过程。结果表明,配位剂焦磷酸钾的加入大大降低了铜与镍之间的沉积电位差,实现了铜、镍的共沉积。改变镍离子与铜离子的浓度比可以实现金属镍的可控析出,获得可用作薄膜热电偶材料的CuNi_(44)合金。此外,CuNi_(44)合金的电沉积属于不可逆的瞬时成核过程,受到扩散步骤和电化学步骤控制,并随着电位负移,沉积过程逐渐由两者混合控制转变为由电化学步骤控制。

The electrodeposition of Cu-Ni alloy was studied electrochemically by cyclic voltammetry,polarization curve measurement,and potential step method.The results showed that the addition of potassium pyrophosphate as a complexing agent greatly decreased the electrodeposition potential difference between Cu and Ni,facilitating the codeposition of Cu and Ni.The Ni content in Cu-Ni alloy coating could be controlled by varying the nickel-to-copper concentration ratio in the electrolyte,and a CuNi_(44) alloy commonly used as a thin film thermocouple material could be obtained.The electrodeposition of CuNi_(44) alloy is an irreversible instantaneous nucleation process,which is controlled by diffusion and electrochemical steps.With the shifting of potential towards the negative direction,the electrodeposition is changed from mixed control to electrochemical step control.