鋅銅合金微柱之製備與其腐蝕行為

Fabrication of zinc-copper alloy micropillars and their corrosion behaviour

本文以微陽極導引電鍍法高電流密度之特性，快速製備富鋅（＞80 at.%）之奈米晶鋅銅合金微柱，基於鋅、銅離子優異之抗菌性、生物相容性，並具備奈米晶體結構能快速腐蝕、釋放鋅與銅離子之優勢，預期可適用於生物醫學領域中生物可降解材料及抗菌傷口敷料。透過改變鍍液之pH值自4.9至6.5，改變螯合物種以抑制銅還原電流，並探討鍍浴中不同鋅／銅離子比（6.67、11.11、33.33、50.00、66.67）對微柱組成及晶體結構之影響，製備具單一相且成分均勻之微柱，使其腐蝕（降解）過程穩定進行。所得微柱透過EDS mapping與line scan分析化學組成及XRD分析晶體結構。微柱在腐蝕測試前，先經鑲埋及研磨拋光，使其露出微柱之橫截面，浸泡於0.9wt%之生理食鹽水中量測開路電位（Open Circuit Potential, OCP），並進行電化學阻抗頻譜（Electrochemical Impedance Spectroscopy, EIS）及塔弗極化（Tafel polarization）等分析以探討其腐蝕行為。

In this paper, the zinc-rich (>80 at.%) nano-crystalline Zn-Cu alloy micropillars were prepared by the microanode guided electroplating method. The alloys reveal antibacterial and excellent biocompatibility so that they are suitable for biodegradable materials suitable for antibacterial wound dressings in the biomedical field. Due to the characterization of nanocrystals, the alloys take advantage to readily release both zinc and copper ions through corrosion. The pH value in the bath was in the range from 4.9 to 6.5; the ionic ratio of zinc/copper was fixed at 6.67, 11.11, 33.33, 50.00 and 66.67 to study their effect on the composition and crystal structure of the micropillars. The micropillars in a uniform composition and single phase favor a steady corrosion behavior.
Elemental distribution in micropillars were analyzed by EDS mapping and line scan; crystalline structure was explored by XRD analysis. The corrosion test of the micropillars, exposed with their cross-section, was performed in 0.9 wt% saline. Data of the open circuit potential (OCP), Tafel polarization and electrochemical impedance spectroscopy (EIS) were compared.