Technology And Property Of Composite Coating By ARC Spraying Feeding From Outside

Nowadays arc sprayed composite coatings are mostly prepared by cored wires. But the high cost has restricted their application. In this paper, we have given the conception of outside-feeding arc spraying technology and prepared composite coatings by solid wires. Structure, combining intensity, microstructure, and wear resistance of the coatings are characterized by the orthogonal test, SEM, and XRD etc.Arc sprayed composite coatings are composed of iron-chromium compounds, iron oxide, and aluminum oxide with layered structure. Quality of the coatings is closely related to the spraying current, distance, and pressure of the atomizing air. Great quality of the coatings can not obtained under a bigger or lower parameter.Technical parameters which effect the combining strength of the arc sprayed coating are (from main to minor in turns) spraying current, atomizing air pressure, spraying distance, and spraying potential. The micro-hardness of the coatings are effected by (from main to minor in turns) spraying distance, spraying potential, atomizing air pressure, and spraying current.Combining intensity of the coating and the substrate is increased when heat-treated under 450℃. But when the temperature enhances above 450℃, the combining intensity decreases evidently. Also, the combining intensity descends with the increasing of the coating thickness Wear mass loss of the coating descends .with the increasing of spraying current and atomizing air pressure under dry frication. But it ascends with the increasing of spraying potential and distance. The wear mechanism of the coating attributes to the brittleness shedding of the hard phase particles going with a slight micro-cutting.