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3D printers; Additives; Cost effectiveness; Costs; Fluidization; Oxidation; Oxide minerals; Oxygen; Thermodynamics; Titanium dioxide; Titanium metallography, Cost effective; Gas-solid fluidization; Kinetics and thermodynamics; Oxidation behaviors; Oxidation mechanisms; Oxide layer; Oxygen gradients; Powder surface, Powders
Abstract:
Gas-solid fluidization is an innovative route to produce cost-effective HDH CP-Ti powders for additive manufacturing. Herein, oxidation behavior of Ti powders after fluidization was investigated with a particular emphasis on the oxide layer in the powder surface. The oxide layer consists of TiO2, Ti2O3 and TiO with overlapping distributions, exhibiting an oxygen gradient from the outer powder surface to the oxide-Ti(O) interface. Underlying oxidation mechanisms of powders were uncovered by the analysis of kinetics and thermodynamics. A model was established to verify the oxygen pick-up of powders. This study is beneficial for the oxidation control of Ti powders during fluidization. © 2020 Elsevier Ltd