——全浸區(qū)
(1. 中國科學(xué)院 海洋研究所, 青島 266071;
2. 東北大學(xué) 材料與冶金學(xué)院, 沈陽 110006)
摘 要: 開展了熱浸鍍鋅(GI)、 鋅-5%鋁-稀土(GF)和鋅-55%鋁-1.6%硅(GL)鍍層鋼板在青島站的全浸區(qū)海水腐蝕測試, 并利用質(zhì)量損失腐蝕測試、 顯微結(jié)構(gòu)分析和電化學(xué)測試, 研究了3種鍍層鋼板的海水腐蝕行為。 結(jié)果表明: GI鍍層的腐蝕電流密度最大, 在流動海水中以很快的速度溶解而又難于形成穩(wěn)定的保護性腐蝕產(chǎn)物膜, 耐海水腐蝕性能最差； GF和GL鍍層的腐蝕電流密度較小, 腐蝕產(chǎn)物具有抑制保護性, 表現(xiàn)出較為優(yōu)異的耐海水腐蝕性能。 對位于海水全浸區(qū)的鋼材基體提供1年保護期所需的鍍層最小厚度分別為: GI鍍層45 μm; GF鍍層18 μm; GL鍍層25 μm； 3種鍍層在海水全浸區(qū)的耐蝕性強弱順序依次為: GL>GF>GI； 如果考慮到局部腐蝕, 那么GF鍍層可能會比GL具有更強的綜合優(yōu)勢。
關(guān)鍵字: 熱浸鍍；熱浸鍍層； 海水腐蝕； 耐蝕性； 全浸區(qū)
——Immersion zone
（1. Institute of Oceanology, Chinese Academy of Sciences,
Qingdao 266071, China;
2. School of Materials and Metallurgy, Northeastern University,
Shenyang 110006, China）
Abstract: The corrosion behavior of hot dipping Galvanized (GI), Galfan (GF) and Galvalume (GL) coated steels exposed to immersion zone of Qingdao site was investigated with seawater corrosion test, microscopy morphology analyses and electrochemical measurements. The inferior performance of GI mainly results from its largest corrosion current density and not forming a stable and protective corrosion product layer in the flowing seawater. The superior performance of GF and GL is attributed to their optimal combination of lower corrosion current densities and more protective corrosion products. The minimum coating thicknesses requirement for one year protection afforded to steel structures exposed to immersion zone are then calculated as: GI, 45 μm; GF, 18 μm; GL, 25 μm. The corrosion resistances of these coatings are therefore readily listed in descend order as: GL>GF>GI. However, the performance of GF immersed in seawater would probably be better than that of GL if pitting corrosion was taken into accounted.
Key words: hot dip; hot dip coating; seawater corrosion; corrosion resistance; immersion zone
