Investigation of High-Velocity Suspension Flame Sprayed (HVSFS) glass coatings

High-Velocity Suspension Flame Spraying (HVSFS) has recently emerged as a potential alternative to conventional HVOF-spraying: employing liquid suspensions instead of dry powder feedstock enables the use of very fine grain-sized particles, resulting in small-sized lamellae. Thin, low-porosity coatings can thus be manufactured. This paper details the first attempt at manufacturing glass coatings using the HVSFS technique: these coatings can have multiple applications (anti-corrosion coatings on metal and ceramic substrates, bio-compatible coatings, etc). A CaO–ZrO2–SiO2 glass frit was selected for this attempt. Excellent potentialities emerged (very low porosity), but some problems still existed (big “droplet-like” features on the coating surface), which have recently been largely overcome thanks to process modifications.