Slurry Erosion of Arc-Sprayed Metal and Composite Coatings

Two grades of stainless steel, 316 and 440-C, in the form of solid wire, and two cored wires, Duocor and 95-MXC, were used. Coatings were made using the Miller BP-400 and TAFA 9000 systems. Slurry jet erosion tests were conducted using a 10 %w/w alumina particle/water slurry. Two alumina particle sizes, 320 and 80 grit (nominal grain diameters 35 μm and 200 μm, respectively) were used at impinging angles of 90° and 20°. The nominal impact velocity of the slurry was 15 m/s and the nozzle-specimen distance 100 mm. The volume loss of material under various slurry erosion conditions was related to the coating properties and microstructure. Results indicate that the wear behavior of arc sprayed materials is dependent on the erodent particle size; for large erodent particle size, the relative erosion is almost independent of the impinging angle, while for the smaller particle size the angle effect is the dominant factor. This behavior can be related to the lamella structure and the relative toughness of the different phases of the coatings.