No abstract

In this research, the effect of electropolishing on the surface quality of the anodised/dyed aluminium foil was investigated. For this purpose, morphology and luminosity of the anodised/ dyed foils as well as the electropolished/anodised/dyed ones were studied by optical microscopy, stereo microscopy, scanning electron microscopy, atomic force microscopy and Photoshop software. The results show that the median of Photoshop/histogram/blue colour for the electropolished/anodised/dyed foils is more than the anodised/dyed foil (169). It is also found that electropolishing pretreatment reduces average roughness R a of the anodised/dyed aluminium foils (from 11?22 to 2?30 nm).

Anodic-composite films containing nano-diamond particles (ND) were prepared on 7000 aluminium alloy using an anodising method. The micro-structures of the film were studied by scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and minitab software (version 16). The results indicate that the micro-hardness and wear resistance of the films were improved using the nano-additive. Thus, the wear loss of the composite (the film anodised in the bath containing of sulphric acid, oxalic acid and 85 g L −1 ND) evaluated by dry sliding friction test for 50 000 cycles at room temperature, was 0.4 mg compared to 3 mg in the absence of ND, a 750% improvement. The friction of ND composite anodic films is significantly less than the samples without the added particles. Moreover, the micro-hardness of the composite film reached a maximum value of 770 VHN. The results also show that the mechanical properties of the composite films are mainly dependent on the structure of the oxide films.

The study has explored the physical and chemical properties of nickel‐boron/nano‐diamond composite coatings upon pre/post heat treatment. The nano‐composite coatings were produced by electroless plating. In fact, the effects of using the nano‐diamond additives (0 g l−1, 0.1 g l−1, 0.3 g l−1, 0.5 g l−1, 0.7 g l−1) were investigated in pre/post heat treatment. According to the results, the micro‐hardness of the nickel‐boron/nano‐diamond composite coating produced in the bath containing 0.5 g l−1 nano‐diamond additive reached to 1005 HV 0.05 upon post‐heat treatment. Also, the corrosion resistance of the nickel‐boron/nano‐diamond composite coatings was modified by using the nano‐additive or heat treatment. But, adding nano‐diamond particles reduced the ductility and wear resistance of the nickel‐boron coatings. We also found, modification of the properties (ductility and wear resistance) of the composite coatings was achieved by using the heat treatment.