Tailoring metal powders by dry nanoparticle coating for powder bed fusion applications

The influence of high intensity mixing of graphene platelets with stainless steel particles in the scope of additive manufacturing is investigated. Therefore, 0.75 vol% graphene platelets were coated onto conventional stainless steel powder as a model material, resulting in very homogenously distributed graphene layers. The specific energy input during mixing was found to be the main factor for increasing the flowability and decreasing the reflectivity of the powder. Furthermore, the resulting surface roughness of the coated powders could be correlated with a theoretical consideration of van der Waals forces. In this way, the mixing process can be controlled regarding its specific energy input to achieve tailored powders for the application in PBF-LB/M. Cubic parts were produced with different laser parameters and analysed. As a result, the admixing of graphene at lower specific energies resulted in a wider process window and parts with a relative density of 99.99% were achieved.