Effect of Ni-P Amorphous Phases on the Corrosion Resistance of a Ni-Al Alloyed Layer Formed by Pulsed Laser Irradiation
Y. Yang and J-D. Hu
A Ni-P electroless deposited coating with crystalline morphology was prepared on an aluminium substrate. A Nd:YAG pulsed laser was used to alloy the materials at the condition of scanning speed 3 mm/s and power densities of 4.31 × 109 W/m2, 5.36 × 109 W/m2 and 6.46 × 109 W/m2, respectively. The phase composition and microstructure of the alloyed layers produced by different laser power densities were identified by X-ray diffraction (XRD) and transmission electron microscope (TEM). Furthermore, the corrosion resistance of the alloyed layer was evaluated by the electrochemical tests. The results showed that Ni-P amorphous phase was formed in the alloyed layer produced at the condition of power density 5.36 × 109 W/m2 and scanning speed 3 mm/s. As a result, the alloyed layer formed at power density 5.36 × 109 W/m2 showed the better corrosion resistance than the other two alloyed layers.
Keywords: Nd:YAG laser, Ni-Al alloy, pulsed laser, TEM, alloyed layer, corrosion resistance