Heef 25 Hard Chrome Plating process

 HEEF 25 is a fluoride-free hard chromium process that offers high current efficiency. It can be adapted for various applications, including normal hard chromium plating, duplex hard chromium plating, and chromium plating of rotogravure cylinders. The process provides advantages such as excellent deposition efficiency, reduced rectifier electricity costs, and good deposit metal distribution. HEEF 25 is known for its bright, hard deposit with high resistance to abrasion. The process also results in a microcracked deposit that enhances corrosion resistance. Regular maintenance and adjustments are necessary to ensure optimal sulfuric acid content and chromic acid concentration in the bath.

To make up the HEEF® 25 - Liquid hard chromium plating bath, follow these steps:

1. Clean the tank thoroughly.
2. Fill the tank to 35% or 40% full with deionized water and heat it to the desired temperature of 55-65 °C.
3. Add the required amount of Chromic Acid Solution (500) while stirring thoroughly.
4. Add the required amount of HEEF® 25 M while stirring thoroughly.
5. Fill the tank to its operating level with deionized water.
6. Analyze the bath for sulfate concentration.
7. Carefully add sulfuric acid to achieve the desired concentration (3.5, 3.22, or 3.68 g/l) while stirring.
8. Place dummy cathodes into the tank and then add the anodes with current for about 4-6 hours at 40 A/dm² (not necessary for hard chromium plating of rotogravure cylinders).
9. Use a mist suppressant from the non-PFOS Fumetrol®  range to reduce spray mist and drag-out losses.
10. Conversions of conventional hard chromium bath to HEEF® 25 - Liquid should be done only after analysis AT ESS ESS TRADING LAB, Coimbatore. ( Contact 9843019701) Email: info@essesstrading.in)
11. Always observe all regulations regarding operations with chromic acid carefully.

Remember, the bath maintenance requires adding Chromic Acid Solution (500), HEEF® 25 A, sulfuric acid, and mist suppressants. Barium carbonate is used for sulfate precipitation in case of excess sulfate.

To make up 100 liters of the Hard Chromium Plating solution using the HEEF® 25 - Liquid process, the following components are required based on the information provided:

A. Conventional Hard Chromium Plating:

• Water fully demineralized: approximately 45 liters
• Chromic Acid Solution (500): 50 liters
• HEEF® 25 M: 5 liters
• Sulfuric acid, chemically pure: 0.19 kg or 190 ml

B. 2nd Step for Duplex Hard Chromium Plating:

• Water fully demineralized: approximately 37 liters
• Chromic Acid Solution (500): 58 liters
• HEEF® 25 M: 5 liters
• Sulfuric acid, chemically pure: 0.2 kg or 200 ml

C. Hard Chromium Plating of Rotogravure Cylinder:

• Water fully demineralized: approximately 37 liters
• Chromic Acid Solution (500): 58 liters
• HEEF® 25 M: 5 liters
• Sulfuric acid, chemically pure: 0.175 kg or 175 ml

These are the quantities needed to make up 100 liters of each type of hard chromium plating solution as per the provided information .

The working parameters for the HEEF® 25 - Liquid hard chromium process are as follows:

• Temperature:
  • Conventional and Duplex: 57 °C (55 - 65 °C)
  • Rotogravure cylinder: 60 °C (55 - 65 °C)
• pH: < 1, does not need to be monitored.
• Densities:
  • Conventional: approx. 1.18 g/cm³ (22 °Bé) at 20 °C
  • Duplex and Rotogravure cylinder: approx. 1.2 g/cm³ (24 °Bé) at 20 °C
• Current densities:
  • Cathodic: 50 A/dm² (30 - 70 A/dm²)
  • Anodic: 25 A/dm² (15 - 35 A/dm²) (about 50% of cathodic)
  • For Rotogravure cylinder, the cathodic and anodic current density depend on the plant in use.
• Current efficiency:
  • Approx. 25.0% at 50 A/dm²
  • Approx. 26.8% at 70 A/dm²
  • Approx. 27.7% at 90 A/dm²
• Rate of deposition:
• Approx. 1 μm/min at 55 A/dm²
• Rate of deposition may be lower when using rotogravure cylinders, depending on the depth of immersion.

  For the maintenance of the HEEF® 25 - Liquid hard chromium process, the following products and chemicals are necessary:

  1. Chromic Acid Solution (500) - Used to maintain the chromic acid concentration in the plating bath.
  2. HEEF® 25 A - A liquid additive containing special HEEF® 25 - Liquid additives, without chromic acid or sulfuric acid, added to maintain the normal amount of additives in the bath.
  3. Sulfuric acid, chemically pure - Used for additions to achieve the required sulfate content.
  4. Barium carbonate - Used for maintenance to precipitate sulfate in case of excess.
  5. Fumetrol® 21 range of mist-suppressants - Can be used for make-up and maintenance to reduce the bath's surface tension and meet local regulations regarding Chromium-VI compounds in the air .

  The Chromic Acid Solution (500) addition rate is typically 80 to 110 ml of HEEF® 25 A per 1000 ml of Chromic Acid Solution (500) depending on the plating operation and parameters used.

  The nominal values for Conventional Hard Chromium Plating (Make-Up A) are as follows:

  • Chromic acid (CrO3): approx. 260 g/l during make-up, 235 – 270 g/l during operation.
  • Chromium-III (Cr3+): < 8 g/l.
  • Sulfuric acid, Chemically Pure (1.84 g/cm³): 3.5 g/l (1.9 ml/l) during make-up, 3.2 – 4.5 g/l (1.74 – 2.45 ml/l) during operation.
  • Chloride (contamination): < 50 mg/l.
  • Total Foreign metals (Cu, Fe, etc.): < 18 g/l
  • The current density for the conventional and duplex hard chromium processes ranges from 30 to 70 A/dm² for cathodic and 15 to 35 A/dm² for anodic. Specifically, the cathodic current density is recommended at 50 A/dm², whereas the anodic current density should be around 50% of the cathodic current density, which would be 25 A/dm². For the rotogravure cylinder process, the cathodic and anodic current densities are dependent on the specific plant in use.

The deposition rate and current efficiency for the HEEF® 25 - Liquid plating process are as follows:

• Deposition Rate:

  • At 40 A/dm²: 43.3 μm/hour
  • At 50 A/dm²: 57.7 μm/hour
  • At 60 A/dm²: 72.2 μm/hour
  • At 70 A/dm²: 86.5 μm/hour
  • At 80 A/dm²: 100.7 μm/hour
  • At 90 A/dm²: 115.0 μm/hour
  • At 100 A/dm²: 129.9 μm/hour (Page 11)

• Current Efficiency:

  • At 40 A/dm²: 23.5%
  • At 50 A/dm²: 25.0%
  • At 60 A/dm²: 26.0%
  • At 70 A/dm²: 26.8%
  • At 80 A/dm²: 27.3%
  • At 90 A/dm²: 27.7%
  • At 100 A/dm²: 28.1% 

Additionally, it is mentioned that the bath temperature should be adjusted respective to the current density, for example, 55°C for 40 A/dm² to 65°C for 100 A/dm² 

To buy this product please contact us 

at 9843019701 or Email info@essesstrading.in 

Electroless nickel plating

 Electroless nickel plating is a chemical process that deposits a nickel-phosphorus alloy onto a substrate without using an external electrical current. The phosphorus content in the alloy can vary, and it's classified into different types based on this content: low phosphorus (1-4% weight phosphorus), medium phosphorus (5-9% weight phosphorus), and high phosphorus (9-12% weight phosphorus).

The mid-phosphorus electroless nickel plating, which contains 6-9% phosphorus, is a popular choice due to its balanced properties. It offers good corrosion resistance in both alkaline and acidic conditions, making it suitable for a wide range of industrial applications. This type of plating also exhibits as-plated hardness from 45 to 57 Rc, and can be heat-treated to increase its hardness to 65 to 70 Rc. It has a faster deposition rate compared to other types of electroless nickel plating, depositing 18 to 25 µm per hour. So, if you're looking for a versatile electroless nickel plating option that offers good corrosion resistance and hardness, mid-phosphorus electroless nickel plating might be the way to go!

Contact us at 9843019701 for more details ESS ESS TRADING COIMBATORE

Acid copper plating hull cell testing

 Acid copper plating hull cell testing is a method used to evaluate the performance of an acid copper plating bath. The test involves plating a small panel (the Hull Cell panel) in a miniature plating tank under controlled conditions. The panel is plated for a set amount of time at different current densities, allowing the operator to observe the effects of the plating bath on the panel.

The Hull Cell panel is typically made of copper and is divided into sections that correspond to different current densities. The operator can then evaluate the quality of the plating at each current density, looking for issues such as burning, roughness, or poor coverage. The results of the Hull Cell test can help the operator determine if the plating bath is operating within its optimal range and identify any issues that need to be addressed. For example, if the plating is burning at high current densities, it may indicate that the bath is too acidic. Here are some common issues that can be identified through Hull Cell testing: 1. Burning or roughness at high current densities: This may indicate that the bath is too acidic or that the brightener level is too low. 2. Poor coverage or thin plating at low current densities: This may indicate that the bath is too alkaline or that the brightener level is too high. 3. Uneven plating across the panel: This may indicate that the bath is not properly agitated or that there are contaminants in the bath. By regularly performing Hull Cell tests and making adjustments to the plating bath based on the results, operators can optimize the performance of their acid copper plating process.

Sulphate Testing In hard chrome Plating Bath

 Hard chrome plating typically involves a sulfate-based bath, and the sulfate concentration is an important parameter to monitor. The sulfate concentration in the bath can be determined using the following methods:

1. **Kocour Method**: This is a standard method for measuring sulfate concentration in hard chrome plating baths. It involves adding barium chloride to the solution, which reacts with sulfate ions to form barium sulfate. The precipitate is then filtered, dried, and weighed to determine the sulfate content. 2. **Gravimetric Method**: In this method, a known volume of the plating bath is evaporated to dryness, and the residue is weighed. The sulfate content is then calculated based on the weight of the residue. 3. **Spectrophotometric Method**: This method uses a spectrophotometer to measure the absorbance of a solution containing barium sulfate at a specific wavelength. The absorbance is then used to calculate the sulfate concentration. 4. **Ion Chromatography**: This is a more advanced method that involves separating the sulfate ions from the solution using a chromatographic column and then measuring the concentration of sulfate ions using a conductivity detector. When performing these tests, it's important to follow the specific procedures and standards recommended by the plating bath supplier or industry guidelines to ensure accurate results.

Hull Cell Test for Plating Solutions

 

A Hull Cell test is a diagnostic tool used in the electroplating industry to evaluate the performance of a plating bath. It involves plating a small panel (typically made of copper or zinc) in a miniature plating tank called a Hull Cell. The cell is designed to simulate the conditions of a full-size plating tank, allowing operators to observe the effects of different current densities on the plating process.

The test panel is placed at an angle in the cell, with one end closer to the anode (positive electrode) and the other end closer to the cathode (negative electrode). This creates a gradient of current densities across the panel. The operator then applies a specific current to the cell for a set amount of time, typically around 10 minutes. After the plating process, the panel is removed and examined for various characteristics, including: 1. Deposit thickness: The thickness of the plated metal is measured at different points on the panel to determine the uniformity of the plating process. 2. Surface appearance: The operator looks for signs of defects, such as roughness, nodules, or pits, which can indicate problems with the plating bath or process. 3. Color: The color of the plated metal can provide clues about the composition and condition of the plating bath. By analyzing the results of the Hull Cell test, operators can make adjustments to the plating bath or process to optimize the quality and efficiency of the plating process.

Typical Acid-Sulfate Bath Hull Cell Panel Results

The schematic shows the cell has two sides that are parallel, and two that are not parallel. The side that slants off has a blank plate installed to receive the plate, while the other side supports the anode. The plate’s closest side receives more current than the side that is further away. In effect, it receives the plate at the end experiences a higher current density. It is easy for the deposit to be “burned” (note the darker color in the drawing).

On the other side, the current density is generally lower than what is recommended for bath operation (note the light coat in the drawing). Quality plate is laid between the two extremes. How wide the usable coat in between is tells the technician if he needs to adjust the bath. It also shows what the problem might be, whether with the low current or the high current end. The commercial bright acid-copper bath we used had two brighteners, one for low-current and the other for high-current density performance.

Other Acid-Sulfate Bath Hull Cell Panel Results

On rare occasion, other problems might arise. One of these was tiny spots where plating did not take on the cell panel. This proved to be caused by tiny particles from the anodes that effectively insulated their point of attachment, effectively preventing plate from depositing.

Another problem was a swirling pattern on the plate. The panel was shiny and there were no pits, so this difficulty did not suggest the bath was completely dysfunctional, but it suggested the bath needed carbon filtration, followed by introducing fresh brighteners. After doing that, a repeat Hull Cell performance indicated normal bath behavior.

Finally, there was the rare occurrence of plating at the upper and middle ranges of the cell panel, but little to no plate at the lower range. This problem can be more serious if initial low current-density plating is indicated. It is good to check for anode to cathode current density ratio. Yes, the cathode (the piece receiving plating) and the anode (the negatively charged electrode) function best when the ratio of their current densities falls within a given range as well. For bright copper, a ratio of between 1:1 and 2:1, anode: cathode provides the best performance.

In Conclusion

The information provided here must surely suggest to the reader the practical wisdom of buying a Hull Cell test kit to assure a “healthy” properly maintained electroplating bath as a first line of defense.