Corrosive-wear and Electrochemical Performance of Laser Thermal Sprayed Co30Cr8W1.6C3Ni1.4Si Coating on Ti6Al4V Alloy

Abstract

Co30Cr8W1.6C3Ni1.4Si coatings were fabricated on Ti6Al4V alloy using a laser thermal spraying (LTS). The surface and cross-section morphologies, phases and bonding strength of obtained coatings were investigated using scanning electronic microscopy (SEM), X-ray diffraction (XRD), and scratch test, respectively. The effects of laser power on the coefficients of friction (COFs) and corrosive-wear behaviors of Co30Cr8W1.6C3Ni1.4Si coatings were investigated using a wear tester in 3.5% NaCl solution, and the electrochemical corrosion performance was analyzed using an electrochemical workstation. The experimental results show that the Co30Cr8W1.6C3Ni1.4Si coating is bonded with the substrate in the metallurgical form, and the bonding strengths of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1 000, 1 200, and 1 400 W are 76.5, 56.5, and 55.6 N, respectively. The average COFs of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1 000, 1 200, and 1 400 W are 0.769, 0.893, and 0.941, respectively; and the corresponding wear rates are 0.267 × 105, 0.3 1 78 × 105, and 0.325 × 105 µm /Nm, respectively, which increases with the increase of laser power, the wear mechanism is primarily abrasive wear. The corrosion potential of Co30Cr8W1.6C3Ni1.4Si coatings fabricated at the laser power of 1 000, 1 200, and 1 400 W is −0.05, −0.25, and −0.31 V, respectively, higher than −0.45 V of substrate which enhances the electrochemical corrosion resistance of substrate.