A study was conducted to elucidata the annealing conditions that will produce thermally stable dual phase alloy film, 54vol% Ni3Al phase of L12 structure and a solid solution of Ni containing 10mol%Al. Composite films of 100μm in thickness were prepared from a Watts-type Ni plating bath suspended Al particles of 9.2μm in diameter. Annealing at 1073K for 10.8ks resulted in the formation of thermally stable Ni-16mol%Al dual phase alloy film. X-ray diffraction showed the formation of Ni3Al phase after annealing for 0.06ks at 1073K. Compositional homogenization of the 10mol%Al solid solution, however, required annealing for 10.8ks. XMA images of Ni, Al and O as well as backscattered electron images showed fast grain boundary diffusion of Al and slow diffusion of Al into Ni grains, followed by compositional homogenization. Composite films of 5-28mol% Al were also prepared, and it was found that compositional homogenization of the solid solution proceeded very slowly when the Al content was below 16mol%.
