Effect of particle size on processing of bioactive glass powder for atmospheric plasma spraying

Abstract

The work addresses the effect of the particle size of a bioactive glass feedstock on the processing and microstructure of the resulting coatings obtained by atmospheric plasma spraying (APS). It was observed that the reduction of particle size negatively affects the flowability of the powder. In addition the thermal behaviour (weight losses, glass transitions, crystallisations, etc.) also depended on the particle size of the glass powder. No coating was obtained with the coarser fractions (higher than 200 μm) due to their low melting degree in the plasma. For the intermediate fractions (200–63 μm) coatings were obtained but insufficient particle melting was produced. On the contrary, the finest fraction (<63 μm) needed a fluidiser which enabled the samples to be sprayed.