——飛濺區(qū)
(1. 中國(guó)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 110004)
摘 要: 測(cè)試熱浸鍍鋅(GI)、鋅-5%鋁-稀土(GF)和鋅-55%鋁-1.6%硅(GL)鍍層鋼板在青島站的飛濺區(qū)海水腐蝕行為，并利用腐蝕質(zhì)量損失測(cè)試和顯微結(jié)構(gòu)分析，研究3種鍍層鋼板的海水飛濺區(qū)腐蝕行為。結(jié)果表明：3種鍍層在飛濺區(qū)均未發(fā)生生物污損，腐蝕速度在3個(gè)海水區(qū)帶中最低；GI鍍層由于腐蝕電流密度最大，氧化膜保護(hù)效果不佳，耐海水腐蝕性能最差；GF鍍層由于腐蝕電流大幅度降低，飛濺區(qū)充分的充氣條件促進(jìn)了鍍層的鈍化，因此表現(xiàn)出較為優(yōu)異的耐海水腐蝕性能；由于保護(hù)性的鋅的腐蝕產(chǎn)物被滯留在富鋁的枝晶網(wǎng)絡(luò)中，充分的充氣條件又促進(jìn)了鍍層富鋁相的鈍化，所以GL鍍層在海水飛濺區(qū)表現(xiàn)出最佳的腐蝕性能。對(duì)位于海水飛濺區(qū)的鋼材基體提供1 a保護(hù)期所需的鍍層最小厚度分別為：GI鍍層14 μm；GF鍍層8 μm；GL鍍層4 μm；GF和GL鍍層在飛濺區(qū)的耐蝕性分別是厚度相當(dāng)?shù)?/SPAN>GI的2倍和4倍。
關(guān)鍵字: 熱浸鍍；熱浸鍍層；海水腐蝕；耐蝕性；飛濺區(qū)
Qingdao test station (Ⅲ)——Splash zone
（1. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;
2. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China）
Abstract:The corrosion behavior of hot dip Galvanized (GI), Galfan (GF) and Galvalume (GL) coated steels exposed to splash zone of Qingdao site was investigated with seawater corrosion test and microscopy morphology analyses. Splash zone is less aggressive for hot dip coatings and biofouling does not take place in this zone. The poor performance of GI coating is mainly owing to its largest corrosion current density and less protective oxidation product film under the condition of continuously wet with well-aerated seawater. The better performance of GF coatings is attributed to its lower corrosion current density and more resistant oxidation film formed on the coating surface. Since the protective zinc corrosion products retained in the Al-rich dendritic network slows down further attack, and well-aerated condition promotes passivity of the Al-rich phase, GL coating therefore shows the best corrosion performance in splash zone. The minimum coating thickness requirement for 1 a protection afforded to steel structure exposed to splash zone was then calculated as: GI, 14 μm; GF, 8 μm; GL, 4 μm. The corrosion resistance of GL and GF are therefore four and two fold as that of GI exposed to seawater splash zone.
Key words: hot dip by galvanization; hot dip coating; seawater corrosion; corrosion resistance; splash zone
