Characterizing the interface of nickel-zincate-aluminum thin films

The manufacture of plated computer memory disks requires a complex sequence of processing steps. One of the most important factors affecting disk surface topography and adhesion between nickel and aluminum was found to be the formation and diffusion of a zincate thin film at the nickel-aluminum interface. To improve the adhesion, the strength of the weak link (the zinc layer) must be increased. This can be accomplished by alloying the zinc layer with the aluminum and nickel layers by co-diffusion, which is accelerated at high temperatures, or by keeping the zinc layer very thin. Surface topography can be modified by changing the metallurgical properties of the substrate, promoting the diffusion of elements between layers at elevated temperatures, or adjusting the zincating bath parameters.