Effect of Composition on Mechanical Properties of Hydroxyapatite/TiO₂ Coating Fabricated by Suspension Plasma Spray

抄録

This study aims at observing the effect of composition on mechanical properties of Hydroxyapatite/TiO₂ coating fabricated by suspension plasma spray. During plasma Spray, which is only commercial method for biomedical application, extreme high temperature decomposes calcium phosphate and the plasma-sprayed HAp coating then contains amorphous phases. SPS is a modification method of conventional plasma spray techniques to overcome the challenge in use of nano particles using suspension. Interfacial strength of the SPSed coating was determined by tensile test. Acoustic Emission (AE), Infrared Ray (IR) camera and Digital Image Correlation (DIC) techniques were used in-situ to observe damage behavior of the coating until fracture. Results showed that the interfacial strength has increased gradually by increasing the weight percentage of TiO₂. AE signal could be observed when microcracks at interface initiated. IR image also observed inelastic increases in temperature during inelastic deformation in Stress-Strain curves after initiation of microcracks. DIC images exhibited accumulated strain at coating layer. Such multi-modal measurement validly revealed damage mechanisms of accumulated strain and microcracks in the interface layers until fracture.