Wear mechanism of electrodeposited amorphous Ni-Fe-P alloys①
(1. College of Mechanical Engineering, Fuzhou University, Fuzhou 350002, China;
2. Wuhan Institute of Materials Protection, Wuhan 430030, China)
2. Wuhan Institute of Materials Protection, Wuhan 430030, China)
Abstract: The wear mechanism of amorphous Ni-Fe-P coating was discussed. The wear resistance of the amorphous Ni-Fe-P coatings was tested on a Timken wear apparatus, and the wear track of the amorphous Ni-Fe-P coatings as-deposited and heated at various temperatures was observed by SEM. The results show that the wear resistance reaches a maximum value at NaHPO2·H2O concentration of 5 g/L, and heating at 400℃. The wear mode of the coating will change with the
heating temperature increasing from pitting+plowing at 200℃to pitting at 400℃, and to plowing at 600℃. The pits on the worn surface of the amorphous Ni-Fe-P coating result from the tribo-fatigue fracture. The cracks of spalling initiate at pits and propagate at certain angle with the sliding direction on surface, and then extend into sub-surface along the poor P layers or the interface between layers. Finally under repeated action of the stress in the rubbing process the cracks meet and the debris forms. The generation of the pits and spalling is related with the internal stress, brittleness and layer structure of the amorphous Ni-Fe-P coating.
heating temperature increasing from pitting+plowing at 200℃to pitting at 400℃, and to plowing at 600℃. The pits on the worn surface of the amorphous Ni-Fe-P coating result from the tribo-fatigue fracture. The cracks of spalling initiate at pits and propagate at certain angle with the sliding direction on surface, and then extend into sub-surface along the poor P layers or the interface between layers. Finally under repeated action of the stress in the rubbing process the cracks meet and the debris forms. The generation of the pits and spalling is related with the internal stress, brittleness and layer structure of the amorphous Ni-Fe-P coating.
Key words: Ni-Fe-P coating; amorphous alloy; wear mechanism