Influence of the Spray Angle on the Properties of HVOF Sprayed WC–Co Coatings Using (−10 + 2 μm) Fine Powders

Robot based deposition of WC-Co HVOF coatings on HSS cutting tools as a substitution for solid cemented carbide cutting tools

“…This effect is comparable to spraying with very low spray angles. The deposition rate correlates directly with the spray angle [13]. Spray strategy II leads to significantly better results (see figure 3b).…”

Prediction of Coating Properties of Thermally Sprayed WC–Co on Complex Geometries

“…Yet, this approach is costly in resources (sophisticated handling robots) and time and does not always pose a viable solution (Ref 10). Perhaps a better suited approach is to extensively examine the negative effects of non-optimal spray kinematic parameters on the coatings (Ref [10][11][12][13][14][15][16] and derive appropriate tolerances in their variability during the spray process, with respect to the requirements of the specific end application. The variability of the spray kinematic parameters is a function of the shape being sprayed, the relative position of the spray gun and the speed of rotation of the part (or equivalently of the translation of the spray gun over the surface, when a plane-type geometry is sprayed).…”

Water-lubricated tribological behavior of WC-Ni coatings deposited by off-angle HVOF spraying

“…Off-angle spraying is indispensable for thermal spray technologies in industrial practice to coat components of complicated shape [1][2][3]. It has been reported that off-angle thermal spray may lead to notable degradation of coatings features and characteristics, for surface features mainly including higher porosity (lower density) and cracking [1,5], and for surface characteristics including lower microhardness [1,4,5], lower fracture toughness [2,5] or less compressive residual stress [4,5], respectively. Among the different thermal spray technologies, high-velocity oxy-fuel (HVOF) spraying has advantage in the off-angle spraying capable of obtaining denser coatings over other techniques such as plasma spraying and wire arc spraying, as a result of the higher velocity of powders accelerated by the HVOF spray flame [1].…”

“…It has been reported that off-angle thermal spray may lead to notable degradation of coatings features and characteristics, for surface features mainly including higher porosity (lower density) and cracking [1,5], and for surface characteristics including lower microhardness [1,4,5], lower fracture toughness [2,5] or less compressive residual stress [4,5], respectively. Among the different thermal spray technologies, high-velocity oxy-fuel (HVOF) spraying has advantage in the off-angle spraying capable of obtaining denser coatings over other techniques such as plasma spraying and wire arc spraying, as a result of the higher velocity of powders accelerated by the HVOF spray flame [1]. Since the plasma spray and wire arc spray processes are associated with low velocity of sprayed powders, the deposited coatings suffered great oxidation due to the high-temperature heating of sprayed powders with longer dwelling time in the flame, and the limited oxidation during HVOF spraying may be a dominant factor to obtain a relatively denser coating preferably for spraying non-oxide ceramic-metallic composite coatings [6][7][8][9][10].…”