Mechanical Properties of Plasma-Sprayed Mullite-Reinforced Titania-Bioglass Composite

Abstract

Bioceramics have been extensively used for various medical applications including hip and knee prostheses, tissue engineering scaffolds, and dental implants. Bioceramics, particularly bioglass, are desired because of their bioactivity but are often limited by their inherent brittleness. To compensate, composites have been formed to obtain unique properties where both bioactivity and mechanical integrity can be achieved. Mullite-reinforced titania–bioglass (TiO2–BG) composites were therefore deposited using plasma spraying technique. The microstructure of the coating materials were analyzed for their morphology and microstructure using scanning electron microscopy/energy dispersive spectrometry. Mechanical properties of the coatings were tested using three-point bend test, indentation test, and pin-on-disk wear test to determine their fracture strength, fracture toughness, and wear resistance, respectively. The addition of mullite fibers improved the fracture strength and wear resistance of TiO2–BG composites while having minimal effect on fracture toughness. After the addition of mullite, failure mode was bimodal, failing intergranularly and by fiber pull-out. Although mullite fibers have not been particularly used for medical applications, fiber reinforcement has shown efficacy in mechanically reinforcing composites of various medical applications.