2024铝合金表面无铬钛锆转化膜的制备与性能

采用钛酸盐和锆酸盐为主盐,开发了一种应用于2024铝合金表面的无铬钛锆转化膜。通过扫描电镜 (SEM)、能谱分析 (EDS)、中性盐雾实验、动电位极化曲线和电化学阻抗谱对转化膜的表面形貌、成分及耐蚀性能进行了表征和分析。结果表明：制备的无铬钛锆转化膜由微米级的微小颗粒组成,膜层均匀平整,无明显缺陷;无铬钛锆转化处理后的2024铝合金,经中性盐雾168 h,无明显腐蚀产物产生;钛锆转化膜具有较低的腐蚀电流和一定的钝化能力,可有效的提高铝合金的耐蚀性能。

Preparation and Performances of Chromium-free Titanate-zirconate Conversion Coating on 2024 Aluminum Alloy

A novel chromium-free titanate-zirconate conversion coating on 2024 aluminum alloy was prepared, the corrosion resistance of the coatings was evaluated by means of potentiodynamic measurement, NSS test and AC impedance spectra. The morphology and composition of the coatings were characterized by means of SEM with EDS. The results showed that the titanate-zirconate conversion coating is made up of micro particles and shows a smooth flat surface with a few defects. After NSS test for 168 h, only a little corrosion products can be observed on the surface of the titanate-zirconate conversion coating on 2024 aluminum alloy, implying that the conversion coating possesses passivation ability to a certain extent. Therefore, the prepared chromium-free titanate-zirconate conversion coating can provide excellent corrosion protection for 2024 aluminum alloy efficiently.