Mechanical properties of the supersonic atmospheric plasma sprayed Ca[sbnd]P coating post-processed by a microwave-hydrothermal method

Abstract

Coating fabricated by supersonic atmospheric plasma spraying (SAPS) technique is post-treated by a microwave-hydrothermal (MH) method. In this case, after the surface defects are reduced, the mechanical properties between the sprayed CaP coating treated by the MH process and carbon/carbon (C/C) substrate are also studied. Accordingly, observation of the surface morphology and the cross-section of the coating are all performed by scanning electron microscopy. The phase composition and the chemical groups are examined by X-ray diffraction and Fourier Transform Infrared. Besides, a number of required measuring methods have been performed, which include shear strength, modulus of elasticity, hardness and friction coefficient. They are carried out using shear test, nanoindentation, and friction test in the mechanical property evaluation. It's obviously found that the MH method after the SAPS technique can enhance the mechanical properties at the coating-C/C substrate interface. The results show that the bonding strength of the coating after MH treatment, which is 10.46 MPa, increases by 33.25% compared to the bonding strength of the sprayed CaP coating (7.85 MPa). And the modulus of elasticity and hardness are also increased (33.74% and 38.13%). Additionally, the friction coefficient of the coating has been improved in the stable state. Finally, in simulated body fluid (SBF) experiment, the sprayed CaP coating after MH post-treatment also exhibits the bioactive behavior.