电镀锌钢硅烷-有机膦酸复合钝化膜的制备及性能表征

利用N-(β-氨乙基)-γ-氨丙基三甲氧基硅烷(AAPTMS)、γ-(2,3-环氧丙氧基)丙基三甲氧基硅烷(GPTMS)和1-羟基亚乙基-1,1-二膦酸(HEDP),在电镀锌钢基体上制备了一种新型硅烷-有机膦酸复合钝化膜.X射线光电子能谱、傅立叶变换红外光谱以及中性盐雾试验、动电位极化曲线和电化学阻抗谱测试表明:该复合钝化膜主体结构由Si—O—Si、Si—O—P等组成;120 h中性盐雾试验后白锈面积小于5%,达到铬酸盐彩色钝化膜水平;且其腐蚀反应呈现更为明显的阳极扩散控制特征,属于物理阻挡机制.

Preparation and Characterization of the Silane-Phosphonic Acid Composite Passivation Coating for Electrogalvanized Steel

A new silane-phosphonic acid composite passivation coating process has been developed for the protection of electrogalvanized steel based on N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane(AAPTMS),γ-(2,3-epoxypropoxy)propyltrimethoxy-silane(GPTMS) and 1-hydroxy ethylidene-1,1-diphosphonic acid(HEDP).The results of X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR),potentiodynamic polarization scan,electrochemical impedance spectroscopy(EIS) and neutral salt spray(NSS) tests indicated that the major structure of the prepared silane-phosphonic acid composite passivation coating consisted mainly of Si—O—Si and Si—O—P bonds.The area of white rust was not more than 5% of the total panal after 120 h NSS test,which could be compared favourably with the chromate colour passivation coating.However,the corrosion reaction on the anode of the silane-phosphonic acid composite passivation coating had more distinct diffusion control characteristics and belonged to the physical blocking mechanism.