A novel method to control the release rate of halloysite encapsulated Na2MoO4 with Ca2+ and corrosion resistance for Q235 steel

The natural halloysite nanotubes were used as the nanocontainer to load Na 2 MoO 4 corrosion inhibitor , and the release rate of Na 2 MoO 4 was further controlled by wrapped with the CaMoO 4 end stopper through adding with Ca 2+ . The variable release rates were fulfilled by the formation of CaMoO 4 end stopper with different strength, and the release time can be adjusted from one to dozens of hours. Moreover, the prepared complex corrosion inhibitor is also an acid-responsive smart material, which can quickly release the large amount of corrosion inhibitors under acidic conditions through the decomposition of insoluble CaMoO 4 complex on the surface or end of halloysite. In addition, the epoxy coating mixed with 10 wt% Ca 2+ treated Na 2 MoO 4 loaded halloysite can provide the highest corrosion resistance and sustained release of the corrosion inhibitor to achieve corrosion healing in the coating defects.