在热镀锌钢板表面制备了硅烷钒锆复合钝化膜。用X射线光电子能谱(XPS)、射频辉光放电发射光谱(rf-GD-OES)和傅里叶变换衰减全反射红外光谱(ATR-FTIR)表征了钝化膜的组成结构, 分析了硅烷钒锆复合钝化膜的成膜机理。结果表明: 硅烷之间互联构成了硅烷钒锆复合钝化膜的主成膜成分, 无机缓蚀剂均匀分布在膜层中。钝化膜表面Si2p的XPS窄幅扫描谱100.7 eV处的拟合峰和红外光谱在波数1 100 cm-1 Si—O吸收峰变宽加强, 表明硅烷以Si—O—Zn键的形式化学吸附在锌的表面, 硅烷分子之间通过Si—O—Si键相互交联;红外光谱中1 650和1 560 cm-1的两个酰胺特征峰, 结合910 cm-1的环氧特征峰的消失, 表明γ-GPT的环氧基团在氨基活性氢的诱导下开环和γ-APT的氨基之间发生聚合反应形成交联的空间网状结构;rf-GD-OES分析发现钝化膜0.3 μm处存在一层富氧层, 钝化反应生成的ZrF4, ZrO2和钒盐等无机物均匀分布在钝化膜中。分析膜层组成结构和成膜前后的ATR-FTIR光谱, 研究了成膜过程中发生的物理过程和化学变化, 提出了硅烷钒锆复合钝化膜的成膜机理。

A composite silanes-V-Zr passive film was overlayed on hot-dip galvanized steel. Attenuated total reflection Fourier transformed infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometer (XPS) and radio frequency glow discharge optical emission spectrometry (rf-GD-OES) were used to characterize the molecular structure of the silanes-V-Zr passive film. The mechanism of film formation was discussed. The results show that the silane molecules are crosslinked as the main film former and inorganic inhibitor is even distributed in the film. The fitting peak of 100.7 eV in XPS single Si2p energy range spectra of the composite silanes-V-Zr passive film and the widening and strengthening of the Si—O infrared absorption peak at 1 100 cm-1 indicate that the silanes were adsorbed on the surface of zinc with chemical bond of Si—O—Zn, and the silane molecules were connected with each other by bond of Si—O—Si. Two characteristic absorption peaks of amide at 1 650 and 1 560 cm-1 appear in the infrared spectroscopy of the composite silanes-V-Zr passive film, and a characteristic absorption peak of epoxy groups at 910 cm-1 disappears in the infrared spectroscopy of the passive film. The results indicate that γ-APT can be prepared through nucleophilic ring-opening of ethylene oxide in γ-GPT molecule to form C—N covalent bonds. The rf-GD-OES results indicate that there is a oxygen enriched layer in 0.3 μm depth of the composite silanes-V-Zr passive film. Moreover, ZrF4, ZrO2 and some inorganic matter obtained by the reaction during the forming process of the composite silanes-V-Zr passive film are distributed evenly throughout the film. According to the film composition, the physical processes and chemical reactions during the film forming process were studied by using ATR-FTIR. Based on this, the film forming mechanism was proposed.