Abstract HVOF cermet layers are increasingly viewed as an alternative to galvanic hard chrome layers for applications with high demands on wear and corrosion protection. The WC-Co-Cr layer is one of them. The WC-Co-Cr layers were produced with different HVOF systems: Jet-Kote, Diamond Jet, and JP5000. With all three systems, dense and well-adhering layers could be produced. This article considers HVOF sprayed WC-10Co- 4Cr as a generic coating type for replacing hard chrome plating. The friction, wear, adhesion, and corrosion performance of the HVOF WC-10Co-4Cr coatings are compared against the performance of a commercial hard chrome coating system. The article also evaluates effect on the coating adhesion of corrosion through the coating and penetrating along the interface at the coating edge. Paper includes a German-language abstract.

Abstract In this paper, the corrosion characteristics of two coatings of the same generic Ni-Cr-Si-B self-fluxing type applied by the High Velocity Oxy-Fuel process are assessed in the as-sprayed condition. One of the coatings is also investigated after post spray treatment with polymer sealing and after vacuum furnace fusion. The paper focuses on the effect of corrosion behaviour in terms of electrochemical measurements and observed mechanisms in relation to the coating microstructure. Microstructural characteristics and the static corrosion behaviour of the coatings are investigated. It is observed that the crack corrosion and the local attack at the lamellar boundaries dominate the corrosion in the layers in the sprayed state and in the sealed state, while the pitting corrosion, which results from the failure of hard phases, plays the main role in the melted layer. Paper includes a German-language abstract.