Optimization of sol–gel coating on the surface of aluminum alloy powder for corrosion protection in the condition of ultrasonic radiation

In order to improve the corrosion resistance of an aluminum alloy powder (aluminum–copper–iron), a traditional sol–gel process (tetraethoxysilane [TEOS] was used as the precursor) was carried out in accordance with orthogonal experiments (L9(34)) in the first step. Solvent, reaction temperature, molar concentration of TEOS, and molar concentration of water were selected as the controllable factors. The optimum condition was obtained by means of the orthogonal analysis. In the second step, the encapsulation process was carried out under ultrasonic radiation based on the optimal reaction condition obtained from the traditional sol–gel process. We also studied the effects of ultrasonic power and radiation time on the encapsulation process. Finally, the corrosion inhibition factor of the encapsulated powder was reaching up to 99.5% in the hydrochloric acid (1 mol/L) solution. And the mean particle size of encapsulated powder was only 5.9% larger than that of the unencapsulated powder. Combined with the FTIR, XRD, DLS, SEM, and EDS analyses, it was concluded that an extremely thin layer had encapsulated on the aluminum alloy powder.