The cold spray process is sensitive to variations in feedstock and requires consistent powder properties, particularly flowability, to produce uniform structures. Poor powder flow causes a cascade of effects arising from erratic feeding including deposits with void spaces and inconsistent geometries. These issues result in deposits which are not suitable for testing and prevent sample replication, hindering experimental evaluation of deposits. Powder flowability is largely affected by the material preconditioning and storage conditions; with flowability directly affecting the deposit properties of deposition efficiency (DE), porosity, and surface finish. In this study, the flowability and deposit quality of a fluoropolymer-based powder was evaluated with changing pretreatment conditions. Powder flowability was analyzed by mass flowrate (g/s), the Carr angle of repose, and the Hausner ratio. Flowability was evaluated for powders as received, after sieving (45-100 μm), with drying at elevated temperature (80 °C), with inert gas vacuum purging, and after 72 hrs. of exposure to high relative humidity (95% RH). Powders exposed to humid conditions were also dried under inert gas vacuum purging to determine the effectiveness of the process as a reconditioning method. Preconditioned powders with the highest flowability according to these tests were sealed in metal containers, stored under 95% RH for one week, and reevaluated to determine the ability of this preconditioning and storage method to protect materials from exposure to undesirable conditions. Next, the effect of preconditioning on cold spray deposit quality was evaluated for the fluoropolymer-based powder with the best and worst flowability. The choice of spray conditions was informed by simulation of particle velocity and temperature distribution at impact using one-dimensional compressible flow modeling, couple with thermal analysis of the powder. The DE was determined gravimetrically, surface roughness was evaluated using a profilometer, and microstructure was evaluated using a scanning electron microscope (SEM). The ability to manipulate powder flowability through simple preconditioning methods and quickly evaluate the properties of the feedstock before use in the manufacturing process, coupled with straightforward and rapid evaluation the resultant deposit; will save time and money, and accelerate research efforts, compared to evaluating powder suitability by trial and error.

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