THE EFFECT OF PULSED-LASER ANNEALING ON WEAR AND CORROSION PROPERTIESOF ELECTROLESS NI-P PLATING

Electroless nickel-phosphorous alloy was plated onto quenched and hard ened stainless steel. Laser surface treatments by YAG laser beams were carried out with the objective of improving both the wear and the cor rosion resistance of the platings. The friction and wear properties of the laser-treated platings were compared to unplated, untreated plate d, and 400-degrees-C heat-treated plated substrates in pin-on-disc tes ts under unlubricated conditions. It was shown that laser treatments g ave above a ten percent reduction in the friction coefficient compared with unplated substrates, and that controlled laser-treated plating i mproved the wear resistance of untreated plating to a level equivalent to 400-degrees-C heat-treated plating. It was found that the salt-spr ay corrosion resistance of the laser-treated platings was much greater than the unplated material and the 400-degrees-C heat-treated plating . The laser treatment is capable of improving both wear and corrosion resistance; and the wear resistance is externally governed by the hard ness of the plating, and the corrosion resistance is governed by the c rystal structure, especially the amount of amorphous nickel.