الفهرس | Only 14 pages are availabe for public view |
Abstract Nickel-Phosphorus (Hi-P) samples were prepared in the amorphous state using the electrodeposition technique. The phosphorus content in ranged between 15-26 atomic percent. Crystalline nickel was also prepared using the same technique. X-ray diffraction studies showed bhat the tendency of glass formation generally increases with increasing the P-content in the alloy. At the eutectio composition (around 20 at % P) there is a significant local order similar to that of the corresponding crystal. This plays a role in determining the properties of this alloy. On heating Ni-P alloys from 150-650°C, they transform into the more stable crystalline state. Differential thermal analysis showed that this transformation occurs in two steps. The first step occurs at temperature ranged between 340-355”C and was attributed to the precipitation of small size nickel crystals while the second step occurs between 400-412°C and was attributed to the precipitation of large size nickel phosphide crystals. Microhardness measurements indicated that Ni-P alloys are more harder than crystalline nickel. As the phosphorus content increases, the hardness number of .the alloys decreases. The increase in the hardness number is attributed to the presence of certain crystalline phases within the amorphous matrix. |