Wear performance and mechanism of electroless Ni-P coating

An electroless Ni-P coating has been deposited onto an AISI 1020 plain carbon steel by using an acid bath based on NiCl2, as source of nickel cations. The tribological behavior under dry non-lubricated conditions has been evaluated by employing the pin-on-disc test, where the pin was made of AISI 52100 steel. The effects of the heat treatment carried out at 400 and 260 degrees C for 1 and 25 h, respectively on the hardness, friction and wear behavior of the coatings were investigated and compared against the properties of the unplated and as-deposited samples. Both optical and electron microscopic techniques were used to study the wear surface. It was shown that the wear resistance was greatly increased with both heat treatments, the treatment performed at 400 degrees C being a little more effective, although no influence was observed on the frictional coefficient.