Effects of Addition of Waste Toner Particles on Tribological Properties of Ni-P Coatings Before and After Heat Treatment

This study investigated the tribological properties of Ni-P coatings produced by the electroless plating technique with various amounts of waste toner particles added to the plating bath. The properties were examined before and after a heat treatment process involving 60 minutes of heating at 400ºC. The impact of the concentration of toner particles in the plating bath on the properties and also the microstructure, phases, micro-hardness and wear mechanism and characteristics of the modified coatings were investigated. Field emission scanning electron microscopy (FESEM) images showed that toner particles were homogeneously distributed in the Ni-P matrix. The addition of 1 g/L of waste toner particles to the plating bath significantly increased the wear resistance of the coating and reduced its coefficient of friction (COF) to as low as 0.25. Although heat treatment increased the micro-hardness of all of the coatings, it did not lead to a significant improvement in the wear resistance of the toner-containing coating compared to the conventional coating. The presence of toner particles in the plating bath decreased the coating growth rate from 0.16 to 0.08 µm/min. Increasing the concentration of toner particles from 1 to 5 g/L decreased the toner content of the resulting Ni-P coatings, leading to reduced micro-hardness and consequently increased wear rate of the produced composite coatings.