The Effect of Composite Stabilization on the Repair Behavior of Weathering Steel Rust Layer Under a Simulated Highly Polluted Industrial Atmospheric Environment

The effects of Cu3(PO4)2-CuSO4 composite stabilization on assisted repair behavior of weathering steel rust layer after damage were studied by using 0.1 mol/L NaHSO3 solution and 65% relative humidity to simulate a highly polluted industrial atmospheric environment (corrosion grade CX). The results show that the corrosion rate of the self-repairing sample (without stabilization treatment) decreases first and then increases, while that of the stabilizer-assisted repair sample continues to decrease. The rust layer in the damaged area and the undamaged area of the self-repairing sample present a through layer, and there are longitudinal banded pores between the layers. While corrosion is taking place, the impedance and self-corrosion potential of the self-repairing sample decrease first and then increase, while the self-corrosion current density is opposite. The self-corrosion potential and impedance of the assisted repair sample gradually increase, and the self-corrosion current density decreases. After 10 d of repair, the repair rate Rρ of the assisted repair sample is 2.03 times that of the self-repair sample. After 20 d of repair, the repair rate of the self-repair sample becomes negative, and the assisted repair sample is 1.44 times that of the repair at 10 d. Stabilizer-assisted repair promotes the formation of amorphous hydroxyl oxides at the damage site through the enrichment of Cu and Cr, inhibits the corrosion of the “acid regeneration cycle” and the diffusion of the corrosive medium in the rust layer, and improves the repair rate of the rust layer.