Improve stability of dicalcium silicate / Zirconia composite coatings by post-spraying heat treatment

The long-term stability of plasma-sprayed dicalcium silicate (C ₂S) composite coatings is determined by the phase composition, crystallinity, and other properties. Zirconia reinforcement and post-spraying heat treatment are applied to C₂S coatings simultaneously in this work. The stability of the coating increases evidently by reinforcement with 70wt% zirconia and heat treatment at 800°C for 4 hours. SEM reveals that the smooth glassy surface of the as-sprayed coatings is replaced by randomly dispersed crystals. Tris-HCl immersion test results show that the dissolution rate of the composite coatings decreases after the heat treatment. © 2005 Trans Tech Publications, Switzerland.