Sherardizing and Characteristic of Zinc Protective Coating on High-Strength Steel Bridge Cable Wires
Zinc protective coatings on high carbon SWRH82B-1 steel were sherardized to markedly improve corrosion resistance of the high-strength steel bridge cable wires (SBCW). Sherardizing parameters have been optimized by optical microscopy (OM) /scanning electron microscopy (SEM), X-ray diffraction (XRD) and potentiodynamic polarization tests. The sherardizing coatings are composed of the loose outer layer (§-FeZn13 phase) and the dense inner layer (δ- FeZn7 phase) with higher hardness. Addition of Y2O3 activator slightly increases the corrosion resistance of sherardized steel wire in comparison with CeO2. A thicker coating corresponds to a higher sherardizing temperature or a longer heating duration, but an extra thick coating is unfavorable for thru-microcrack existed in the inner layer. Good quality of sherardized wires ( higher corrosion resistance and longer duration than conditional hot-dip-galvanized one) can be produced with the zinc-rich powder containing 7.5wt.% CeO2 activator and 25wt. % SiO2 filler under 400°Cfor 6h.
Zhengyi Jiang and Chunliang Zhang
J. H. Jiang et al., "Sherardizing and Characteristic of Zinc Protective Coating on High-Strength Steel Bridge Cable Wires ", Advanced Materials Research, Vols. 97-101, pp. 1368-1372, 2010