SELECTIVE OXIDATION AND THERMAL STABILITY OF Ni-Zr AMORPHOUS ALLOYS

Oxidation and crystallization behaviours of three Ni-Zr amorphous alloys have been studied during isothermal annealing at the temperatures below their crystallization temperature by means of electrical resistance measurement, differential scanning calorimetery and X-ray diffraction. Selective oxidation of Zr has been found in these alloys. As a consequent, it increase the thermal stability of surface layer constructed by Ni_(37)Zr_(63) but decreases that constructed by Ni_(65)Zr_(35). The reason of this effect has also been discussed.