Exploring the hindering mechanism of element Ti on the adherence of CoO‐bearing one‐coat enamel/steel

Abstract

The effect of element Ti on adherence between a CoO‐bearing single‐layer enamel coating and steel was investigated. Falling‐weights tests were carried out and cross‐sections at interface of the enamel/substrate were analyzed with a scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Results show that addition of TiO2 reduced adherence of the enamel coating by hindering the formation of anchor‐like alloy precipitates. The decrease of anchor points lies in the following three reasons: I. The diffusion path of Co2+ ions to the interface was lengthened because of the blocking effect of rutile and the FeTiO3 crystals; II. Formation of CoTiO3 crystals leads to a reduction of free Co2+ ions; III. Co–Fe precipitates form away from the enamel/substrate interface, as FeTiO3 crystals provide extra surface for the nucleation of Fe–Co alloy precipitates.