Liu Yong,Dong Wenzhong*.The influence of electrical parameters on the substrate surface activation uniformity during alloy-iron plating[J].Plating & Finishing,2025,(04):7-12.
doi: 10.3969/j.issn.1001-3849.2025.04.002电参数对合金镀铁基体表面活化均匀性的影响
- Title:
- The influence of electrical parameters on the substrate surface activation uniformity during alloy-iron plating
- Keywords:
- iron-based alloy coatings; engine crankshaft; uniform activation; voltage difference between positive and negative electrodes; current density
- 分类号:
- TQ153.2
- 文献标志码:
- A
- 摘要:
- 在发动机曲轴轴颈表面制备铁基合金镀层时，镀层与曲轴基体表面的结合强度是制约镀层发挥其性能的关键因素。在电镀初始阶段，曲轴基体表面是否得到有效均匀活化是影响镀层与基体结合强度的关键因素。铁基镍钴合金镀铁液中，NiCl2·6H2O和CoCl2·6H2O浓度分别为80 g/L及30 g/L，镀液相对质量密度1.22～1.23，镀液温度40 ℃～50 ℃，镀液pH值0.6～0.7。在保持阴阳极面积匹配、电极距离和活化时间等工艺规范相同的条件下，通过调整正负向电压和电流密度进行电化学活化处理，对采用不同电压差和电流密度进行活化后的轴颈表面状态及制备的镀层金相进行了对比、研究。结果表明：保持正向电压5 V，正向电压比负向电压高出0.2 V，电流密度取5 A/dm2时，活化处理3 min，基体表面可实现有效均匀活化，活化处理后制备的镀层与基体界面无缺陷，获得了高结合强度的沉积层。
- Abstract:
- When preparing iron-based alloy coating on the engine crankshaft journal surface, the bonding strength between the coating and the crankshaft substrate surface is the key factor restricting the coating performance. In the initial electroplating stage, whether the crankshaft substrate surface is effectively and uniformly activated is a key factor affecting the bonding strength between the coating and the substrate. In iron-based nickel & cobalt alloy plating solution, the NiCl2·6H2O and CoCl2·6H2O concentrations were respectively 80 g/L and 30 g/L, and the specific gravity of the plating solution was about 1.22-1.23. Moreover, the temperature was set to 40 ℃-50 ℃ and the pH value was 0.6-0.7. Under the same process specifications such as maintaining the anode and cathode matching areas, electrode distance, and activation time, electrochemical activation treatment was carried out by adjusting the positive and negative electrode voltages and current densities. The journal surface state after activation using different voltage differences and current densities, as well as the metallographic structure of the prepared coating, were compared and studied. The results indicate that when the positive electrode voltage is maintained at 5 V, the positive electrode is 0.2 V higher than the negative electrode, and the current density is set at 5 A/dm2. After 3 minutes activation, the substrate surface achieve effective and uniform activation, and there is no defect at the prepared coating interface with the substrate, resulting in a deposition layer with high bonding strength
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