Troubleshooting Brass Plating

Tekno Conducting Salt - Meta Conducting Salt: Brass Plating Solutions

Meta Conducting Salt (Yellow-Red Brass)

• Description:
  Meta Conducting Salt is used for brass plating in both barrel and rack systems. It produces a bright, rich gold color resembling 20-24k gold. This solution is effective in both warm and cold conditions, but optimal performance is achieved in warmer environments. The resulting brass can vary in color from light yellow to deep reddish-gold based on temperature and current adjustments.

• Solution Composition:

  1. Meta Conducting Salt: 75-150 g/L (recommended: 100 g/L)

  2. Ammonium Chloride: 3 g/L

• Operating Conditions:

  1. Current Density: 3-4 A/ft² (recommended: 5-8 A/ft²)

  2. Voltage: 2.5-3.0 V (recommended: 3.4-4.0 V)

  3. pH: 9.8-10.8

  4. Temperature: 40-50°C (recommended: 45-60°C)

• Preparation:

  1. Clean the plating tank and fill it with 2/3 of the working water level.

  2. Dissolve Meta Conducting Salt completely.

  3. Fill the tank to the working level and add Ammonium Chloride. Mix well.

• Equipment:
  Use steel tanks, or those lined with plastic or rubber. Equip with anodes and cathodes and ensure appropriate heating if working at warm temperatures.

• Maintenance:
  Analyze the solution weekly to check copper and zinc levels, and add Meta Conducting Salt as necessary:

  1. Copper: 6.2-7.2 g/L (recommended: 8.5-9.5 g/L)

  2. Zinc: 5.6-6.2 g/L (recommended: 7.5-8.5 g/L)

  3. Sodium Cyanide: 12.0-14 g/L (recommended: 14.0-16.0 g/L)

• Regularly check cyanide levels and add sodium cyanide to maintain balance. Add Ammonium Chloride (2.0-3.0 g/L) daily during plating to maintain brass color.

• Anodes:
  For decorative brass plating, use anodes with 60% copper and 40% zinc. For a deeper brass color, use brass anodes with 70% copper and 30% zinc.

• Plating Sequence:

  1. Cleaning: Use alkaline cleaner B1 (40-60 g/L) at 80°C for 2-5 minutes, then rinse with clean water.

  2. Electrical Cleaning: Use E-60 (80 g/L) at 70°C for 2-3 minutes, current density: 50-100 A/ft², then rinse with clean water.

  3. Acid Dip: Use fat remover 105 (10-15% by volume) for 30 seconds at room temperature, then rinse with clean water.

  4. Nickel Plating: Plate with A-brite, BXB, or B-max.

  5. Clean Water Rinse.

  6. Brass Plating: Apply to achieve a thickness of 0.6-1.0 microns.

  7. Clean Water Rinse.

  8. Cyanide Neutralization: Dip in 2-3% sulfuric acid solution.

  9. Clean Water Rinse.

  10. Anti-Tarnish Dip: Use copper-brass anti-tarnish solution.

  11. Drying: Air-dry or bake.

Tekno Conducting Salt (Yellow-Green Brass)

• Description:
  Tekno Conducting Salt produces a yellow-gold plating with a greenish tint. The solution works in both warm and cold conditions, but performs better in warmer environments. Color can range from light yellow to yellow-green, with the ability to adjust shades by varying temperature and current in the same bath.

Troubleshooting for Brass Plating Solutions:

1. Poor Adhesion:

   • Causes: Insufficient brass salt, low cyanide, oil or oxide residue, improper cleaning.

   • Solutions: Add more brass salt, increase cyanide, ensure thorough cleaning and rinsing.

2. Excess Copper:

   • Causes: High copper content, lack of ammonia, low zinc.

   • Solutions: Lower temperature, add ammonium chloride, adjust zinc cyanide levels.

3. Faded Color:

   • Causes: Low temperature, insufficient copper or cyanide, high current.

   • Solutions: Increase temperature, add copper cyanide or sodium cyanide, adjust current.

4. White Deposits on Anodes:

   • Cause: Lack of ammonia or ammonium chloride.

   • Solution: Add ammonium chloride.

5. Scaly Appearance on Anodes:

   • Cause: Excess cyanide.

   • Solution: Reduce cyanide levels.

6. Dark Film on Anodes:

   • Cause: Lead contamination.

   • Solution: Avoid using tanks or anodes with lead.

7. Rough Surface:

   • Cause: Suspended solids.

   • Solution: Filter solution or let settle overnight.

8. Quick Color Fading:

   • Cause: Inadequate rinsing, low free cyanide.

   • Solution: Improve rinsing and add sodium cyanide as needed.

9. Spotty Brass Plating:

   • Cause: Trapped solution in small openings.

   • Solution: Use a potassium hydrogen tartrate dip and rinse thoroughly.

10. Inconsistent Plating and Excess Gas Formation:

    • Cause: High free cyanide or low metal content.

    • Solution: Adjust cyanide levels and add brass salt if necessary.

11. Plating Not Adhering:

    • Causes: Electrical connection issues, high cyanide, dirty workpieces.

    • Solutions: Check electrical connections, adjust cyanide, clean workpieces.

12. Thickened Solution and Precipitation:

    • Cause: Low temperatures causing carbonate formation.

    • Solution: Increase temperature, filter out precipitates, or replace old solution.

To Increase Solution Density:
Add approximately 15 g/L of brass salt to achieve a 12-15 Baumé density. Dissolve the brass salt before adding it to the tank.