摘要
The changes in structure and the hardness of two electroless deposited Ni-P alloy coatings (with P content of 1.5 and 9.5 wt pet) with heat treatment have been studied by XRD and TEM. The deposits containing 1.5 wt pet P can be represented as an fee NiP supersaturated solid solution of 5 similar to 10 nm microcrystallites, whereas the deposits containing 9.5 wt pet P are amorphous. The heat treatment process induces crystallization of amorphous Ni to Ni phosphides and fee Ni. Both of the deposits reach maximum hardness after annealing at 400 degrees C for 1 h. All coated steel specimens are inferior in fatigue strength to uncoated steel specimens mainly due to the poor fatigue resistance of the coating itself.
The changes in structure and the hardness of two electroless deposited Ni-P alloy coatings (with P content of 1.5 and 9.5 wt pet) with heat treatment have been studied by XRD and TEM. The deposits containing 1.5 wt pet P can be represented as an fee NiP supersaturated solid solution of 5 similar to 10 nm microcrystallites, whereas the deposits containing 9.5 wt pet P are amorphous. The heat treatment process induces crystallization of amorphous Ni to Ni phosphides and fee Ni. Both of the deposits reach maximum hardness after annealing at 400 degrees C for 1 h. All coated steel specimens are inferior in fatigue strength to uncoated steel specimens mainly due to the poor fatigue resistance of the coating itself.
