Influence of Spray Angle on Distribution of WC-Co-Cr Coating Produced by HVOF Spraying

When high velocity oxyfuel (HVOF) sprays complex shape parts, it is almost impossible to maintain a fixed angle between spray flame and substrate surface. Studying the effect of spray angle on coating characteristics is necessary. The present study investigates the influence of the concave radius size on the deposition rate. As feedstock material, an agglomerated and sintered WC-10Co-4Cr powder with a size distribution of 15∼45 μm was used. For the spray experiments the process parameters were held constant, while the radii were selected of 10, 15 and 25 mm in concave profile. It has been generally shown that the spray angle has a great effect on coating deposition rate. The reduction of the spray angle results in a decrease of the deposition rate. A significant degradation of the coating properties is found less to 30°. The relationship between the coating's distribution and spray angle with different curvature radius was deduced.