| 摘要 |
The invention relates to a process for preparing thin films which are 15 μ m-thick and comprise two layers, the first one of 5 μ m and the second one of 10 μ m, made of Zn-Ni-P alloys through a process of co-deposition on a carbon-steel support, in two stages, the first stage in autocatalytic regime and the second stage in galvanostat regime, with electrolytes consisting of solutions of zinc sulphate, nickel sulphate, sodium hypophosphite and phosphoric acid and phosphorous acid, respectively, using complexing agents and pH correction agents, such as sodium citrate and ammonium chloride. According to the invention, the process comprises two processes: a. a process of autocatlytic co-deposition in electrolytes consisting of NiSO, ZnSOand NaHPO*HO, where the complexing agents and pH-stabilizing agents are CHNaO*2HO and NHCl, the film adherence and structure improving agents are CHOand SC(NH)and the pH correction agent is the NaOH solution, the process taking place in a heat-resistant glass vessel having a capacity of 600 cm, the anode being a platinum plate, at a working temperature of 70...90°C, a bath pH ranging between 9...11, a NiSO: ZnSOratio of 4:1 and a deposition time ranging between 30...120 min, and b. a process of electrochemical co-deposition using a glass electrolytic cell with the capacity of the tank (1) of 1600 cm, the cathode (4) being a 20 x 20 mm steel plate, the anodes (3) being platinum plates having the dimensions 40 x 50 x 0.2 mm, the reference electrode being made of saturated calomel, a temperature- and pH-controlling probe (2), where a magnetic stirrer (6) of variable rotation speed and embedded in teflon stirs the electrolyte consisting of NiSO*7HO, ZnSO, HPOand HPO, at a HPO: HPOratio of 10:1, the complexing agents and pH-stabilizing agents are CHNaO*2HO and NHCl and the pH correction agent is the HSOsolution. |
