(中國石油大學(xué)(華東) 材料科學(xué)與工程學(xué)院，青島 266580)
摘 要: 采用化學(xué)轉(zhuǎn)化法在Zn-55%Al-1.6%Si熱鍍層表面構(gòu)建了三價(jià)鉻轉(zhuǎn)化膜，通過3D形貌儀、掃描電鏡(SEM)、X射線光電子能譜(XPS)、拉曼光譜和接觸角儀等表面分析手段，以及中性鹽霧試驗(yàn)和電化學(xué)測試方法表征了轉(zhuǎn)化膜的結(jié)構(gòu)、組成和性能。利用脈沖電位法對(duì)轉(zhuǎn)化膜的結(jié)構(gòu)進(jìn)行調(diào)控，研究了脈沖電場調(diào)控作用對(duì)轉(zhuǎn)化膜結(jié)構(gòu)和性能的影響。結(jié)果表明：構(gòu)建的三價(jià)鉻轉(zhuǎn)化膜表面具有多尺度的微觀形貌特征，微米級(jí)的兩相結(jié)構(gòu)上分布著納米級(jí)顆粒和微孔。加載陰極脈沖方波可加速轉(zhuǎn)化膜的生成，提高膜中氫氧化物的含量和膜的疏水性，還可減少膜表面的微裂紋以及Cr(Ⅵ)的含量；當(dāng)脈沖方波電位φP=-100.0 mV時(shí)，構(gòu)建的轉(zhuǎn)化膜具有最佳的耐蝕性，能夠提高對(duì)鍍層表面的臨時(shí)保護(hù)作用。外加脈沖電場對(duì)轉(zhuǎn)化膜的結(jié)構(gòu)和性能具有積極的調(diào)控作用。
關(guān)鍵字: 熱浸鍍鋼；化學(xué)轉(zhuǎn)化膜；三價(jià)鉻；脈沖電位法；耐蝕性
（School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China）
Abstract:Cr(Ⅲ) chemical conversion passivation (TCP) exhibits a high potential as substitutes for the environmentally unfriendly chromate metal-surface pre-treatment methods. In this paper, Cr(Ⅲ) conversion coating was constructed on the surface of hot-dip Zn-55%Al-1.6%Si, and the structure and properties of the conversion coating were regulated by pulse potential method (PPM). 3D topography, SEM, XPS, Raman spectrum, contact angle, neutral salt spray test and electrochemical test were used to study the corresponding structure, composition and properties of the conversion coatings. The results of micro morphology and roughness analysis show that the surface of Cr(Ⅲ) conversion coating has the characteristics of multi-scale micro morphology, and nano-scale particles and holes are distributed on the micro-scale two-phase structure. The results also show that the application of external electric field reduces the micro-cracks and the content of hexavalent chromium, accelerated the formation of conversion coating, and the content of alkaline hydroxide in the coating increased as well. The contact angle measurement shows that the structure of conversion coating controlled by the pulse potential method has more certain hydrophobicity. When the pulse square wave potential φP=-100.0 mV, the TCP conversion coatings have the best corrosion resistance, which can improve the temporary protection of the hot-dip coating surface. The external pulse electric field has a positive regulatory and control effect.
Key words: hot-dip coated steel sheet; chemical conversion coating; trivalent chromium; pulse potential method; corrosion resistance
