Effect of adding Lanthanum (La3+) on surface performance of Ni-P electroless plating coatings on RB400 support anchor rod steel

摘要

Anchor rod, a common support material in engineering which is often used in civil engineeringstructures, such as roadway, mines, underground tunnels and rock slope supporting and so on. Owingto the complex service environment and condition, the anchor rod is susceptible to wear and corrosion.In order to improve the wear and corrosion resistance of anchor rod and increase the service lifetimeduring operation, Ni-P coatings have been prepared on RB400 anchor rod steel via electroless plating.Rare earth element of Lanthanum (La3+) with various concentrations have been added into theelectroless plating solution. The surface morphologies, phase constitutions and cross-sectionalcomposition distributions of phosphorus contents in the coatings were characterized by scanningelectron microscope (SEM), X-ray diffraction (XRD) and glow discharge optical emissionspectroscope (GDOES). Tribological performance and corrosion resistance of the obtained Ni-Pcoatings were investigated by reciprocating wear testing machine and electrochemical workstation.The results showed that the La3+ which played an important role on refining and modifying grain, hadsignificantly influences the properties of Ni-P coatings. In terms of wear resistance, 0.25 g/L is theoptimum supplementation, but the effect of La3+ on the wear resistance is not significant. While theLa-coatings with outstanding corrosion resistance exhibit the highest corrosion potential, lowestcorrosion current density and maximum resistance value between solution and substrate when thesupplementation is 0.50 g/L.