Synchronous chemical conversion process on 6061/7075 aluminum alloys and galvanized steel

Purpose This paper aims to focus the synchronous chemical conversion technology–based titanium/zirconium composite on 6061, 7075 aluminum alloys and galvanized steel. Design/methodology/approach The effects of pH, temperature, reaction time and other process parameters on the corrosion resistance of the three metal surface coatings were investigated by copper sulfate drop and electrochemical corrosion performance tests under a certain content of H2TiF6 and H2ZrF6. The surface morphology and element distribution of the conversion coating were analyzed by scanning electron microscope and X-ray photoelectron spectroscopy. Findings The results show that the optimal synchronization chemical conversion conditions of 6061/7075 aluminum alloys/galvanized steel are controlled as follows: H2TiF6 2.2 mL/L, H2ZrF6 1 mL/L, pH 3.9, conversion temperature 35°C and conversion time 120 s. Originality/value Multi-metals chemical conversion coating can be obtained simultaneously with uniform corrosion resistance and surface morphology. The presence of microdomain features in multiple metals facilitates simultaneous chemical conversion into coatings.