Effect of porosity sealing treatments on the corrosion resistance of high-velocity oxy-fuel (HVOF)-sprayed Fe-based amorphous metallic coatings

Characterisation of three-dimensional porosity in an Fe-based amorphous coating and its correlation with corrosion behaviour

“…4). This detrimental effects have been reported by others [8,12,33,62]. It is known that through-porosity facilitates the formation of direct paths between the corrosive environment and the substrate.…”

“…4), it is associated with the porosity defects in the coating. Many works showed that coating porosity significantly increased passive current density of the coating [12,34]. As shown in Fig.…”

“…One of the main applications of Fe-based amorphous coatings concerns the improvement of the substrate corrosion resistance. However, the high corrosion resistance of the coating could be deteriorated by coating porosity and other defects [12,34]. Through-porosity is much more detrimental to the corrosion resistance of the coated material compared with non-through porosity (Fig.…”

“…It is well known that the corrosion resistance of the coated base materials is strongly related to the coating porosity [6][7][8][9][10][11][12][13][14][15][16]. The coating delamination and peeling off caused by corrosion is one of the most commonly encountered failure types.…”

“…Compared with non-through porosity, through-porosity demonstrates much more sensitive to the corrosion resistance as it forms direct paths between the corrosive environment and the substrate [7,8]. In recent years, a number of attempts have been made to explore the role of porosity in the corrosion behaviour of the thermally sprayed coatings [6,[9][10][11][12][13]. For the thermally sprayed Inconel 625 coating, a distinct difference between the corrosion resistance of coating and the equivalent bulk materials was observed [6].…”