Investigation of the Synergistic Effect of Soft and Hard Particles on Corrosion and Wear Resistance Behavior of Ni-B-PTFE-Si3N4 Electroless Coating on Carbon Steel
Subject Areas : journal of New Materials
Danial Behroozi
1
(-Department of Materials Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran)
Nahid Pirhady Tavandashti
2
(Assistant Professor, Department of Materials Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.)
Keywords: Corrosion Resistance, wear resistance, Electroless Ni-B coating, PTFE Particles, Si3N4 nanoparticles,
Abstract :
In this study, soft PTFE particles and hard Si3N4 nanoparticles were simultaneously introduced into the Ni-B electroless coating and the Ni-B-PTFE-Si3N4 nanocomposite coating was prepared on plain carbon steel. The microstructure and morphology of the coatings were examined by scanning electron microscopy, and the corrosion resistance was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. The results showed that by introducing PTFE particles into the coating bath, Ni-B-PTFE composite coating was successfully prepared. The best corrosion resistance of Ni-B-PTFE coating was achieved when a concentration of 3 g/L PTFE particles were used. The corrosion current density was 2.3 μA/cm2. However, introduction of Si3N4 nanoparticles into the Ni-B coating can also improve the corrosion resistance of the coating. The best corrosion resistance of Ni-B-Si3N4 coating was obtained at a concentration of 4 g/L Si3N4 nanoparticles, with a corrosion current density of 2.2 μA/cm2. Simultaneous application of hard and soft particles in the coating increased corrosion resistance, and the corrosion current density was 0.76 μA/cm2 for Ni-B-PTFE-Si3N4 coating. The results of hardness and abrasion tests showed that the addition of Si3N4 nanoparticles leads to an increase in the hardness and friction coefficient of Ni-B coating from 847 Vickers and 0.6 to 963 Vickers and 0.78, respectively. Nevertheless, the incorporation of PTFE particles reduces the hardness and coefficient of friction to 572 Vickers and 0.35, respectively. Simultaneous application of hard and soft particles resulted a hardness of 871 Vickers and friction coefficient of 0.6.
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