The Research Of Chemical Plating By Ni And Ni-P Alloy On Al₂O₃Ceramic Surface

In this paper, the Ni and Ni-P allow was synthesized by chemical plating onthe Al₂O₃ceramic surface, respectively. The plating morphology and compositionof samples were characterized by the X-ray diffraction（XRD）, scanning electronmicroscopy（SEM） and another analytical tools. It was studied that the density ofmain salt and reductant, the time of coarsening, the PH value, the stabilizer andthe bath temperature effect on the morphology plating, the phase compositionand the bonding strength of plating and the Al₂O₃ceramic systematically.The research results of the process of Ni-P alloy coating showed that whenthe concentration of main salt NiSO₄was25g/L, the concentration of NaH₂PO₂was30g/L, the coarsening time was30min, the water temperature was92℃, thetensile of Ni-P alloy plating and Al₂O₃ceramic substrate was49.9N. The studyon the process of pure nickel coating results showed that when the concentrationof main salt NiSO₄was25g/L, the concentration of hydrazine hydrate was18g/L,the citric acid was17g/L, the concentration of ethylene diamine was40mL/L,plating temperature was92℃, pH value was13, plating time was1h, the tensileof the coating and Al₂O₃ceramic substrate was125N. And under the sameconditions, the tensile of the coating doped La2O3was137N, and contrast withthe pure nickel coatings, the tensile increased slightly.The observations on microstructural results showed that Ni-P alloy coatingsynthesized was cell structure, and cellular fabric arranged closely, no cracksand holes. And the bonding strength between the coating and the matrix Al₂O₃ceramic was poor, the interface of coating and the substrate was “opened”; thepure nickel coating was cell structure, and cellular fabric arranged closely, nocracks and holes, the bonding strength between the coating and the matrixAl₂O₃ceramic was good, and the fracture morphology was “opened” by thecoating itself. The XRD analysis shows that the Ni-P alloy had amorphous characteristics, and the pure nickel coating was amorphous under the platingstate.