Structural transformations in TiC-CaO-Ti3PO(x)-(Ag2Ca) electrodes and biocompatible TiCaPCO(N)-(Ag) coatings during pulsed electrospark deposition

Abstract

Abstract Thick (up to 30 μm) multicomponent biocompatible coatings with high surface roughness (R a > 6 μm) and hardness up to 11 GPa have been obtained by pulsed electrospark deposition (PED). The surface of Ti substrates (BT1-0 brand mark) was treated using TiC-CaO-Ti 3 PO (x) and TiC-CaO-Ti 3 PO (x) -Ag 2 Ca electrodes obtained by self-propagating high-temperature synthesis from the reaction mixtures of 90%(Ti + 0.5C) + 10%Ca 3 (PO 4 ) 2 and 81%(Ti + 0.5C) + 9% Ca 3 (PO 4 ) 2 + 10% Ag. The Ag was doped into the electrode composition in order to provide the antibacterial activity of the PED coatings. The different contents of O and N in the coatings were achieved through the treatment in various environments: Ar atmosphere, air, or distilled water. The PED was performed at single-discharge energies of 3 and 30 mJ. Depending on the PED mode and processing environments, the coatings with different phase compositions were obtained. Cell proliferation tests showed good biocompatibility of Ag-free and Ag-doped PED coatings with low Ag content. The present paper gives a detailed description of PED process and structural transformations at the tip of electrodes during the PED that affect final coating structure.