Bioactive Glass-Ceramic Coatings Synthesized by the Liquid Precursor Plasma Spraying Process

Abstract

In this study, the liquid precursor plasma spraying process was used to manufacture P 2 O 5 -Na 2 O-CaOSiO 2 bioactive glass-ceramic coatings (BGCCs), where sol and suspension were used as feedstocks for plasma spraying. The effect of precursor and spray parameters on the formation and crystallinity of BGCCs was systematically studied. The results indicated that coatings with higher crystallinity were obtained using the sol precursor, while nanostructured coatings predominantly consisting of amorphous phase were synthesized using the suspension precursor. For coatings manufactured from suspension, the fraction of the amorphous phase increased with the increase in plasma power and the decrease in liquid precursor feed rate. The coatings synthesized from the suspension plasma spray process also showed a good in vitro bioactivity, as suggested by the fast apatite formation when soaking into SBF.

Solution Precursor Plasma Spraying (SPPS): A novel and simple process to obtain bioactive glass coatings

“…Only few peaks, corresponding to the TiO2 bond coat, are observed. This finding contrasts with the results obtained by Y. Xiao et al [8], who attributed the high degree of crystallisation in the coating to an inhibited droplet breakup due to high viscosity gel which resulted in insufficient melting of the glass droplets. Nevertheless, in that research long stand-off distances and low energy plasma were used for the deposition of the feedstock.…”

“…In the family of thermal spraying techniques, there is a process known as SPPS (Solution Precursor Plasma Spraying) which has been extensively reported for varied materials (zirconia or hydroxyapatite, among others) but it has hardly been investigated with glass precursors [7]. In a previous research, authors have considered the production of bioactive glass coating by SPPS and SPS processes [8]. However, highly crystallized glass-ceramic coatings were obtained when a fixed sol precursor feedstock was used at given plasma spray conditions.…”