(清華大學(xué)材料科學(xué)與工程系， 北京 100084)
摘 要: 用電位線掃描對(duì)玻美度為30°Bé的三氯化鐵溶液中的FeNi42和Pt 工作電極進(jìn)行陰極極化。 FeNi42的蝕刻過程由溶液中Fe3+向合金界面的擴(kuò)散傳質(zhì)控制， 其蝕刻電流與還原步驟的極限擴(kuò)散電流相等。 應(yīng)用Pt 工作電極的動(dòng)電位陰極極化可以對(duì)合金的蝕刻電流密度進(jìn)行衡量。快速電位掃描獲得的Pt 電極極化曲線上有波峰出現(xiàn)，相應(yīng)于溶液中Fe3+還原為Fe2+。波峰縮短了極限電流平臺(tái)區(qū)，成為利用快掃 描獲得合金蝕刻電流密度的限制性因素。FeNi42自身的陰極極化曲線上也有波峰和曲線轉(zhuǎn)折，相應(yīng)于合金表面的金屬再沉積。不能利用FeNi42電極通過快速電位掃描獲得其蝕刻電流密度值。
關(guān)鍵字: 蝕刻 陰極極化 引線框架
（Department of Materials Science and Engineering, Tsinghua University, Beijing 100084）
Abstract:The cathodic polarization studies of FeNi42 alloy and Pt in FeCl3 solution of 30°Bé by using linear sweep of potential showed that the diffusion of Fe3+ to alloy surface controlled the etching rate of the alloy and that the etching current was equal to the limiting current of reduction. The etching current density of the alloy could be estimated by the cathodic polarization of potential sweep applied on Pt working electrode. Peaks on polarization curves of fast sweep of Pt working electrode, which reduced the limiting current region and was the restricting factor to decide the etching current density by high sweep rate of potential , corresponded to the reduction reaction of Fe3+ to Fe2+. The peak or inflection formed on polarization curves of FeNi42 was related to the deposition processes of metal from solution. Fast sweep of potential performed on FeNi42 alloy was not feasible to measure its etching current density.
Key words: etching cathodic polarization lead frame
