Tailoring hydroxyapatite microspheres by spray-drying for powder bed fusion feedstock

Abstract

The present work deals with a study on the physical characteristics of hydroxyapatite microspheres produced by spray-drying process through different operating conditions. Obtained hydroxyapatite microspheres will be used as powder feedstock in powder bed selective laser processing additive manufacturing technologies where the flowability and the particle size distribution of the powder feedstock is of special importance. Spray air pressure and solid content of the slurries were the most influent parameters to control the final particle size distribution, while higher air pressure and temperatures gave the higher process recovery rate. The use of polyvinyl alcohol as organic binder increased the granules strength. The produced hydroxyapatite microspheres were found to fulfil the powder bed selective laser processing feedstock requirements, keeping the physico-chemical properties of the material. These promising results confirm the use of a spray dryer as an efficient method for the production of hydroxyapatite microspheres for powder bed selective laser processing.