Boron doped diamond thin films on large area Ti6Al4V substrates for electrochemical application

Abstract

Boron doped diamond thin films were grown on titanium alloy substrates (Ti6Al4V) with 36 × 35 × 1.3 mm at 873-933 K at 6.5 × 10 3 Pa during 8 h by hot filament CVD assisted technique. The boron source was obtained from a H 2 line forced to pass through a bubbler containing B 2 O 3 dissolved in methanol (B\C = 6000 ppm). The films were grown on both sides of perforated and non-perforated substrates. Emphasis for diamond growing on perforated substrates have been done in order to increase the active surface area and hereafter to promote an easier electrolyte flow for wastewater treatment. The electrode performance was determined by cyclic voltammetry meas-urements in KCl, KNO 3 , Na 2 SO 4 , HCl, HNO 3 and H 2 SO 4 solutions and the reversibility behavior of the Fe(CN) 6 3-/4-at the Ti6Al4V/Diamond electrode were studied. Also, Scaning Electron Micro-copy and Raman Scattering Spectroscopy were used for morphology and diamond quality evalu-ation, respectively. trodes can withstand corrosive environments and favor al-ternative reactions 5 . The main used substrate was the Si once its presents good characteristics for many applications. More recently, titanium alloy substrate became a good alternative for dia-mond growth since they have higher mechanical strength and electrical conductivity 6 . However some problems re-lated to diamond film delamination became a goal to be overcome. It usually occurs due to the generation of high residual stresses in both films and substrate. Thermal stresses are often high in diamond films as a result of high deposi-tion temperatures and the low thermal expansion coefficient of diamond compared to Ti6Al4V 7 . Some solutions for this problem have been found, as the low deposition tempera-ture and stress relieves by slow temperature dropping, and have been considered in this work. Also, an electrochemical investigation for characterization of boron-doped diamond electrodes on Ti6Al4V is one of the purposes of this work. We have carried out electrochemical experiments