A novel sealing and high scratch resistant nanorod Ni-P coating on anodic aluminum oxide

Abstract High scratch resistant nanorod nickel-phosphorous (Ni-P) sealing was fabricated using electroless deposition method on nanoporous anodic aluminum oxide (AAO-np). A two-step anodization process was preferred to develop an AAO-np template on Al alloy. Sensitization and activation processes were proceeded using SnCl2, PdCl2 respectively before Ni-P deposition. Concrete Ni-P was filled in and grown on AAO-np with a pore diameter of 40–60 nm at 6–7 μm height. A top view morphology confirms that the initial Ni-P clusters were transformed into a well-grown cauliflower-like structure during 1hr and 2 hr deposition times, respectively. Symmetric Ni-P nano-rods are formed at the beginning of porous structure in a side view. A possible formation of Ni-P nano-rods on AAO structure results in a potential improvement in indentation and scratch hardness as 3100 MPa and 3350 MPa, respectively.