Influence of Thermally Sprayed WC-Co-Cr Coatings on the Corrosion Characteristics of Ni-Al Bronze Alloy

Abstract

WC-Co-Cr coatings were thermally sprayed onto a Ni-Al bronze (NAB) alloy using the high velocity oxy-fuel (HVOF) process in order to increase the corrosion resistance of the NAB alloy, which is widely used for ship propellers operating in seawater. The superior corrosion resistance of the WC-Co-Cr coated NAB alloy, relative to the uncoated NAB alloy, was demonstrated by plotting their potentiodynamic polarization curves and conducting 80-day duration immersion tests in a 3.5% NaCl solution. The anti-corrosive properties of the WC-Co-Cr coated NAB alloy were improved by shortening spray distances and increasing hydrogen flow rates in the HVOF process.