2021 Volume 61 Issue 1 Pages 326-334
Glass coatings and ceramic coatings are usually used to protect the slabs from oxidation during the reheating process of 60Si2Mn spring steel before hot rolling. In view of the characteristic that the primary glass is able to transform from amorphous phase to ceramic phase during the reheating process, glass-ceramics are potential to become a new type of coating materials with both the advantages of the glass coatings and ceramic coatings. In this paper, glass-ceramic was firstly prepared with solid wastes including vanadium-titanium slag (VTS) and coal gangue (CG). With the increasing content of VTS, the main crystalline phase of the glass-ceramic transformed from cordierite to spinel and hercynite, and the crystallization activation energy (Ek) increased. New glass-ceramic coatings were prepared with the as-prepared primary glass powders with different proportion of VTS. When the proportion of VTS within the primary glass powders was 6% by weight, the glass-ceramic coatings possessed the best anti-oxidation effect of 74.4% at 1100°C for 2 h. The protective mechanism of glass-ceramic coatings was discussed with the results of SEM and EDS. Before crystallization, the amorphous phase within primary glass contributed to good sintering performance, and thus the coatings formed a dense film, slowing down the oxidation caused by the direct contact between oxygen and the slabs. With the increasing temperature, amorphous phase gradually transformed to ceramic phase, preventing the oxidation resulted from the diffusion of Fe ions.
