Study Of Electroless Nickel Plating On Cenospheres

In the paper, the cenospheres surface was modified by electroless nickel plating, it is necessary to activate the cenospheres before electroless plating because its surface does not have the catalyst properties.At present, the activation method of the non-metal mostly used is of Pd activation method. It would be consumed many noble metals and the activation process is complex, so the new activation process without Pd is paid more attention by investigators. In the paper, cenospheres was activated by the activation solution with nickel sulfate and sodium hypophosphite in water. The composition of the activation solut ion and the activation process conditions were studied through the cross and single tests, the optimal composition of the solution and the optimal conditions of the activation process were obtained finally. Mol ratio of NiSO₄ and NaH₂PO₂ is 1 ∶ 4, their total mol is 2. 5mol/L, and adding some active additive A, pH value of activation solution is 7-7.5, the dipping time of cenospheres in activation solution is 2min with ultrasonic surging, temperature of thermal oxidation-reduction reaction is 175℃, time of thermal oxidation-reduction is 50minThe activation pretreatment without Pd can reduce the environment pollution, so it has a bright development foreground.Cenospheres is a kind of fine powder, and its specific surface is high, so the bath stabilization is reduced while doing electroless plating. So it is important to select the feasible process of electroless nickel plating to control the bath stabilization, deposition speed at some extent and dispersing of cenospheres in the bath uniformLy. The plating process conditions, such as temperature, time, bath load were researched, and the plating sets were also designed in this paper. The cenospheres granularity is 1-10μm, bath load is 5g/L, bath temperature is 85-89℃, reaction time is 40-90min which is determined on the requiring of different thickness of coating. The bath solution was urged to...