Effect of the substrate dilution on the room and high temperature tribological behaviour of Ni-based coatings deposited by PTA on grey cast iron

In the present investigation the effect of the substrate dilution on room and high temperature (550 and 700 °C) tribological behaviour of nickel based hardfaced coating deposited by plasma transferred arc onto a grey cast iron was investigated and compared to the uncoated grey cast iron. At room temperature, the wear loss of coatings was independent of the substrate dilution and similar to the grey cast iron. At high temperatures, coating produced with high dilution displayed the highest wear resistance between all the samples. This is attributed to the formation of a protective tribo-layer resulting from the agglomeration of a high amount of oxide debris due to its lower oxidation resistance when compared to the sample produced with low dilution.