(哈爾濱工業(yè)大學(xué) 應(yīng)用化學(xué)系，哈爾濱 150001)
摘 要: 為探索鉻酸鹽鈍化膜提高鋅鍍層耐蝕性的機(jī)理和研究其發(fā)生黑變的初期腐蝕現(xiàn)象，對(duì)電鍍鋅鋼板黑變的動(dòng)力學(xué)規(guī)律進(jìn)行了研究。以濕熱實(shí)驗(yàn)中鍍鋅層表面明度差隨時(shí)間變化的關(guān)系來表征鈍化和未鈍化試片腐蝕的速度，發(fā)現(xiàn)鈍化后的鍍鋅層的腐蝕規(guī)律符合Wagner方程，未鈍化的鍍鋅層的腐蝕規(guī)律符合對(duì)數(shù)方程，并求出了相應(yīng)的腐蝕反應(yīng)的活化能。鈍化使腐蝕反應(yīng)的活化能提高了一個(gè)數(shù)量級(jí)以上。實(shí)驗(yàn)結(jié)果表明該腐蝕是由于氧的向內(nèi)擴(kuò)散和鋅離子的向外擴(kuò)散，鈍化膜的存在影響了腐蝕的歷程。
關(guān)鍵字: 電鍍鋅鋼板；鉻酸鹽鈍化膜；黑變；腐蝕活化能
（Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001, P.R.China）
Abstract:In order to make clear the mechanism of that the chromate passivation film increases the corrosion resistance of the zinc coating and to study the black patina which is a kind of prime corrosion phenomenon, the dynamic regulation about the black patina of electrogalvanized steel sheets has been studied. The corrosion rate of zinc coating is characterized by the relationships of surface lightness differences of chromated and unchromated sheets with test time in humidity cabinet test (HCT). It is found that corrosion regulation of chromated zinc coating conforms to Wagner equation and that of unchromated zinc coating conforms to logarithm equation, and the corresponding activity energy of the corrosion reaction was figured out. It is also found that the passivation makes the activity energy raise more than one order of magnitude. These experimental results show that the corrosion is caused by the diffusion of oxygen towards inner and the diffusion of zinc ion towards external in passivating film, and the existence of the passivating film affects the corrosion mechanism.
Key words: electrogalvanized steel sheets; passivating film; black patina; activity energy of corrosion
