氟化鈉與表面活性劑對超臨界二氧化碳混合氯化鋅浴電鍍鋅之影響探討

The Effect of NaF and Surfactant Concentration on the Zinc Coating Electroplated in Supercritical CO2 Mixed Zinc Chloride Bath

鄭豊陭(Li-Yi Cheng)

指導教授 ： 李春穎

國立臺北科技大學/機電學院/製造科技研究所/碩士(2013年)

https://doi.org/10.6841/NTUT.2013.00709

摘要

本研究藉由超臨界二氧化碳輔助電鍍鋅，並利用氟化鈉與表面活性劑之添加調整鍍層之結構及性質，在電鍍鋅製程中達到更佳的平整性和更良好的抗腐蝕性。整個研究利用OM、SEM、XRD、a-step等實驗設備進行鍍層觀察、微結構量測及粗糙度探討，再透過浸泡腐蝕試驗和動電位極化試驗研究鍍層之抗腐蝕性。在不同電鍍製程之鍍層比較中，利用超臨界二氧化碳輔助電鍍因電鍍液介於氣體與液體之間形成乳化狀，可得到較平整粗糙度、較小晶粒尺寸、較佳鍍層均勻性、較佳抗腐蝕性，而氟化鈉的濃度提高帶給鍍層更低粗糙度及更小晶粒尺寸，表面活性劑之添加可使傳統電鍍得到較好的抗腐蝕性，則綜觀電鍍條件下，得知超臨界二氧化碳輔助電鍍下能避免或降低傳統電鍍鋅製程中添加光澤劑與平整劑，提升電鍍鋅之鍍層平整性與抗腐蝕性。

關鍵字

超臨界二氧化碳 ； 電鍍鋅 ； 氟化鈉 ； 表面活性劑

並列摘要

The thesis studies the electroplating of zinc in the zinc chloride bath mixed with supercritical CO2. The sodium fluoride and surfactant were used as the bath additives to change the structure and property of the coating, and therefore the roughness and corrosion resistance of the zinc coating was investigated. The surface characterization was performed using OM, SEM, XRD, a-step profilometer. Moreover, the soaked corrosion test and potentiodynamic polarization measurement in 3% NaCl solution was employed in the corrosion resistance evaluation. Because of the emulsification of the electrolyte mixed in Sc-CO2, the electroplated zinc produced the coating with smoother surface, smaller grain, better throwing power and higher corrosion resistance. The main role played by the sodium fluoride was to reduce the coating’s roughness and grain size, while the addition of surfactant improved the corrosion resistance. In other words, the CO2 mixed with the electrolyte under the supercritical condition performed the similar function as brighter and leveler in zinc electroplating to enhance the throwing power and corrosion resistance of the coating.

並列關鍵字

supercritical CO2 ； zinc-electroplating ； sodium fluoride ； surfactant

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