(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(yáng) 110006)
摘 要: 采用XRD和TEM對(duì)熱浸鋅鋁合金鍍層在動(dòng)態(tài)充氣海水全浸試驗(yàn)時(shí)所形成的白色腐蝕產(chǎn)物進(jìn)行了研究。 結(jié)果表明：腐蝕產(chǎn)物主要由典型的納米級(jí)Zn4CO3(OH)6·H2O，Zn5(OH)8Cl2和Zn6Al2CO3(OH)16·4H2O微晶組成，而這種納米晶的形成與由吸附引起的Zn2+和Al3+離子的共沉積有關(guān)；鍍層表面腐蝕后首先生成Al(OH)3凝膠，當(dāng)凝膠吸附的鋅離子超過(guò)異相形核的臨界過(guò)飽和度時(shí)，發(fā)生鋅、鋁氫氧化物的共沉淀，生成雙氫氧化物。由于晶體長(zhǎng)大速度較慢不能與沉淀形核同步進(jìn)行，導(dǎo)致鍍層表面形成了微晶狀態(tài)的腐蝕產(chǎn)物。
關(guān)鍵字: 鋅鋁合金鍍層； 納米晶； 腐蝕產(chǎn)物； 共沉積
products on hot dip Zn-Al alloy coating
（1. Institute of Oceanology， Chinese Academy of Sciences，
Qingdao 266071, P.R.China;
2. School of Material and Metallurgy, Northeastern University，
Shenyang 110006, P.R.China）
Abstract:The white corrosion products on hot dip Zn-Al alloy coating exposed to seawater in dynamic aerated immersion were investigated by means of XRD and TEM. The results show that the corrosion products are typical nanometer microcrystals，containing mainly Zn4CO3(OH)6·H2O，Zn5(OH)8Cl2 and Zn6Al2CO3(OH)16·4H2O，and that the formation of the nano-crystalline corrosion products probably is related with the co-precipitation of Zn2+ and Al3+ caused by adsorption. Zn-Al alloy coating seawater attack，Al(OH)3 gel is first produced on the coating surface. Zn and Al hydroxides co-precipitate and form double-hydroxide when the concentration of adsorbed Zn2+ ions by the newly produced gel exceeded the critical supersaturation of the interphase nucleation. However，because the growth of the crystals is too low to keep in step with the nucleation，a layer of nano-crystalline corrosion products are produced on the surface of the coating finally.
Key words: Zn-Al alloy coating； nano-crystalline； corrosion product； co-precipitation
