Optimization and Practice of Surface Electroplating Process for Molybdenum-Copper Alloys

The optimization and practice of the surface electroplating process for molybdenum-copper alloys involve several key aspects for detailed discussion:

I. Surface Pretreatment

Surface pretreatment is a crucial step in the electroplating process, and for molybdenum-copper alloys, the main goal is to remove surface oxides and impurities to improve the adhesion between the electroplated layer and the substrate. Common pretreatment methods include mechanical treatments (such as grinding and polishing) and chemical treatments (like acid and alkaline cleaning). Mechanical treatments can provide a highly smooth surface but may cause defects like scratches. Chemical treatments, especially acid pickling, can remove surface oxides but may create pits. Therefore, a balance needs to be struck in selecting the appropriate pretreatment method based on specific requirements.

II. Electrolyte Composition

The electrolyte composition is a critical factor affecting the quality of the electroplated layer. For molybdenum-copper alloys, a commonly used electrolyte is a Na2MoO4·2H2O-Na2SO4 solution. To improve the complexing ability in the electrolyte and enhance the quality of the plating, additives such as amino sulfonic acid and ethanolamine can be added. Additionally, the concentration of molybdenum ions in the electrolyte is a significant factor affecting the coating thickness, typically controlled within 2–20 μm, and with lithium doping, it can reach up to 50 μm.

III. Electrolysis Conditions

Electrolysis conditions encompass parameters like current density and electrolysis temperature. For molybdenum-copper alloys, the current density is generally controlled within 0.2–2 A/cm², and the electrolysis temperature is typically maintained at 70–85°C. Appropriate current density and temperature ensure a uniform, dense coating with good adhesion to the substrate.

IV. Optimization Practices

  1. Optimization of Process Parameters: Adjusting parameters like the electrolyte composition, current density, and electrolysis temperature can optimize the performance of the electroplated layer. For instance, increasing the concentration of complexing agents in the electrolyte can improve the corrosion resistance of the coating. Suitably raising the current density can increase the density and hardness of the coating.
  2. Equipment Selection and Maintenance: Selecting suitable electroplating equipment, such as plating tanks with good dispersion and coverage capabilities, and high-precision power supplies, ensures the stability and consistency of the electroplating process. Regular equipment maintenance and inspections to promptly identify and resolve issues are also crucial for guaranteeing plating quality.
  3. Environmental Protection and Energy Efficiency: The wastewater and emissions generated during the electroplating process may cause environmental pollution. Therefore, attention should be paid to environmental protection and energy efficiency during process optimization. For instance, adopting a closed-loop system for wastewater recycling and treatment reduces wastewater discharge. Using energy-efficient power supplies reduces energy consumption during the electroplating process.

V. Conclusion

The optimization and practice of the surface electroplating process for molybdenum-copper alloys is a complex yet essential process. By adopting reasonable surface pretreatment, optimizing electrolyte composition and electrolysis conditions, selecting appropriate equipment and maintenance measures, and focusing on environmental protection and energy efficiency, high-performance and stable electroplated coatings can be produced. This will enhance the corrosion resistance and service life of molybdenum-copper alloy products, making them widely applicable in aerospace, electronics, and other industries.