Commercial Scale Uniform Powder Coating for Metal Additive Manufacturing

Abstract

Three-dimensional printing of high laser reflectivity metals and metal matrix composites continues to be a challenge because of loss of laser energy and lack of high-quality composite powders. Modifying powders to enhance the interaction between laser and powder and improve the uniformity of reinforcement is a possible solution. However, traditional powder mixing methods such as ball milling destroy the spherical nature of powders. We report here commercial-scale coating of powder by electroless plating for high laser-reflectivity metals and fluidized bed chemical vapor deposition (FBCVD) for composite powders without changing the sphericity. The results indicated that coating high-laser-absorptivity Co and Ni on Al powder enhances the printability leading to good physical and mechanical properties. Similarly, the composite powder made by FBCVD had a good combination of uniformity, sphericity and flowability, which also exhibited improved printability and excellent mechanical properties for the printed bulk composites.