Controlled Synthesis and Visual Corrosion Protection of Samarium-Doped Zinc Tungstate Materials

Based on the lattice configuration of zinc tungstate, the luminescent samarium-doped zinc tungstate solid solution materials were prepared by doping rare earth ions and applied to the visualization of corrosion protection. Since samarium ion could produce a small amount of red fluorescence, after mixing with the blue-green fluorescence of ZnWO4, the doped material exhibited a strong white fluorescence under 254 nm UV light. The physical shielding properties of the corrosion protective film FeWO4 and the enhanced hydrophobic properties of the material hindered the penetration of corrosion ions. Meanwhile, the increased optical band gap of the doped material enhanced the electron reducibility and slowed down the substrate corrosion process. After 72 h of corrosion, the anticorrosion performance of the ZnWO4 doped with 0.5% samarium ions improved by 169.9% compared with the epoxy resin coating. Interestingly, when corrosion occurred, the loss of fluorescence due to material reaction produced bright dark spots that could be used to monitor the corrosion sites. This work not only enhances the corrosion protection of ZnWO4 materials, but also helps to realize the visualization of metal corrosion sites.