Study On The Mechanism And Techniques Of Chemical Plating Ni And FeNi On Hollow Microspheres

In this paper, the effects of pretreatment process on the chemical plating Ni and FeNi on hollow microspheres were investigated by contrast experiments. A new simplified pretreatment process, alkaline cleaning with NaOH and activation with AgNO3, was obtained. Comparing with the traditional pretreatment processes (alkaline cleaning, roughening, sensitization, activation, reduction), the new pretreatment method eliminated the processes of roughening and sensitization, and incorporated the catalytic reduction with the Ni2+ reduction to achieve the chemical plating Ni and FeNi on hollow microspheres. Experimental results show that the hollow microspheres coated Ni and FeNi were magnetic. The Saturation mag-netization of the hollow microspheres coated FeNi was higher than that of coated Ni.The possible mechanism of chemical plating Ni and FeNi on hollow micro-spheres was suggested as follows:at first, [Ag(NH3)2]+ was absorbed on hollow microspheres surface via hydroxy after alkaline cleaning; then, [Ag(NH3)2]+ was reduced into Ag atom by H2PO2-; the Ag atom was the catalytic center for Ni or FeNi deposition.In the processes of chemical plating Ni and FeNi, the velocity of reaction was increased with increasing the concentration of Ni2+ and reducing agent H2PO2-, temperature and loading, however, decreased with increasing the concentration of [C6H5O7]3-. Inaddition, the pH 8.5-9.5 of bath was suitable for chemical plating Ni and FeNi on hollow microspheres.