| Summary: | 碩士 === 國立交通大學 === 材料科學與工程系 === 90 === In this study, Al（l）/NiO（s）/ Ni（s） interface was produced by squeeze casting. Under low oxygen pressure, heat treatments which were employed at different temperatures induced various intermetallic compound. The experimental results were studies by thermodynamic calculation to investigate the reacting mechanism of Al/NiO/Ni interface. According to thermodynamics, Al forms Al2O3 under the oxygen partial pressure of 1.05×10-56 atm, and, Ni forms NiO at 7.08×10-20 atm. The NiO would decomposed at very low oxygen pressure. In this research oxygen pressure was very low, therefore 3NiO（S）+2Al（s）→3Ni（S）+ Al2O3 （s） was observed in solid state. The result is identical with the thermodynamic consequence. When the temperature is higher than the melting point of the pure Al, the reaction of 3NiO（S）+2Al（s）→3Ni（S）+ Al2O3 （s） formed α-Al2O3 particles which didn’t block the liquid Al to pass through the reaction zone.
NiAl2O4 is the common stable phase in Ni-Al-O system. However in this study, Ar atmosphere is applied owning heat treatments, NiAl2O4 which is affected by the activity of NiO and O2 pressure cannot be formed during this study.
Temperature is the main factor of obtaining NimAln, At 600℃, NimAln can not be observed .During the initial period, the reaction followed .After NiO is depleted, Ni reacted with Al, forming NiAl3 and Ni2Al3.At 1000℃, Ni2Al3 is eutectic from the Al substrate, and NiAl is eutectic to produce NiAl as the temperature up to 1200℃.
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