In this work, three characterization techniques were applied to a set of alloys in fine powder form (TiAl6V4, AlSi10Mg, AlSi7, 316L, ferritic stainless steel, martensitic stainless steel and WC-Co-mixes). We sought deeper understanding of response to humidity and flowability as a result of the powder alloy. Slight tribo-charging (induced and measured using a GranuCharge setup) against metal surfaces was found to occur for all alloys. Although the accumulated charge was small and dissipated quickly. Greater charging occurs if the environment is humid, and if the powder slides against plastic surfaces. Dynamic Vapor Sorption (DVS) was employed to understand the adsorption capacity of powders. It showed that WC-Co-mixes adsorbed much more humidity than the other materials. Some alloys retained some of the adsorbed mass when humidity returned to normal conditions. RPA was tested on powders during exposure to 20-98% RH, which above 80% RH caused declining flowability.