Papers by Author: Zhi Hong Fu

Abstract: Cr-α-Al₂O₃ composite coatings were prepared by direct current deposition experiments from Cr(Ⅲ) plating bath and the thickness of composite coatings could be up to 14 μm. The obtained Cr-α-Al₂O₃ coatings and Cr coatings were characterized by means of EDS, SEM and microhardness measurement. Results revealed that Cr-α-Al₂O₃ coatings exhibit fine-grained structure with uniform surface and the highest microhardness values(692 HV) when the α-Al₂O₃ content of coatings was 15g/L, although some pores and defects are still present in the coatings. Analysis of Tafel curves indicated that the presence of α-Al₂O₃ in the Cr coatings show better features in the corrosion resistance both in H₂SO₄ and NaOH solution than those prepared from the bath without α-Al₂O₃.

Abstract: This paper presented the composite coatings of nickel with graphite particle on the aluminum substrate using a nickel sulfamate bath. Effects of graphite particle concentration on the surface morphologies of the composite coatings were investigated. The inclusion of graphite particle into metal deposits was dependent on many process parameters, including particle concentration, current density, pH and temperature. Results of SEM and XRD demonstrated that graphite particle had successfully deposited on that nickel matrix; besides, the surface morphology of coatings obtained from sulfamate bath containing 2g/L graphite particle dispersed more uniformly than the ones with higher concentration.