Electrodeposited Ni-Al composite coatings with high Al content by sediment co-deposition

Sediment co-deposition (SCD) was adopted to develop Ni-Al particle composite coatings. The SCD Ni-Al particle composite coatings have much higher volume fraction of Al particles in coatings with low particle loading in bath than the conventional electrodeposited (CED) Ni-Al composites. 30-35 vol% of Al particles was incorporated in composite coatings at a particle loading as low as 40 g/l. It was found that the volume fraction of Al particles in composite coatings was strongly affected by particle loading up to 40 g/l, but is independent of current density and Off/On time of stirring. The Guglielmi model is employed to explain the effects of deposition parameters. The diffusion treatment of as-plated composite coatings was performed at various temperatures and times. Single-phase γ′-Ni3Al coating was formed after diffusion treatment.