Bioconductivity and mechanical properties of plasma-sprayed dicalcium silicate/zirconia composite coating

Dicalcium silicate (C2S)/yttria stabilized zirconia (YSZ) composite coatings possessing better durability and more superior mechanical properties than pure C2S coatings were produced by atmospheric plasma spraying. The microstructure and phase composition of the composite coatings were determined by scanning electron microscopy and X-ray diffraction. The bioconductivity of the coatings was evaluated in vitro by incubating in simulated body fluids (SBF). Apatite was observed to precipitate even on coatings comprising more than 70% YSZ after immersion in SBF for 7 days. The changes of the mechanical properties of the composite coatings due to immersion in SBF were also investigated. The durability was found to increase with a larger YSZ content in the coatings. Deterioration of the mechanical properties can be attributed to the degraded interlamellar or cohesive bonding due to fast dissolution of C2S. This study reveals factors affecting the durability of the C2S/YSZ composite coatings in simulated physiological environment and suggests means for improvement to address clinical needs.