Electroless gold plating additives

The MID Au-89 process deposits a thin chemical gold layer on the nickel-phosphorus bath plating layer. This product is designed to use as the final coating of MID . Potassium gold cyanide is added separately to the bath to provide the metal content of the bath.

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Product Description

Electroless gold plating additives

MID Au-89 electroless gold plating additive



The MID Au-89 process deposits a thin chemical gold layer on the nickel-phosphorus bath plating layer. This product is designed to use as the final coating of MID . Potassium gold cyanide is added separately to the bath to provide the metal content of the bath.


Features and advantages

High stability Long solution life
Consistent, bright coating

Improve appearance

Wide operating range Easy to control
Can add Reduce the cost of cylinder opening


Physical and chemical properties


Clear, water-white liquid
odor Tasteless
Flash point Not flammable
Solidifying point -2 ℃
Minimum storage temperature 0 ℃


Equipment requirements 


Reinforced PP , 316 stainless steel lined with Teflon


Teflon coated stainless steel heater or Teflon steam pipe


Continuous filtration requires 10 micron PP filter element to filter


need. Recommendation 50 fpm ( 15 mpm ) the amount of ventilation


Bath steps

Pure water

50% ( v/v )

MID Au-89 electroless gold plating additive

50% ( v/v )

Potassium gold cyanide ( 68% gold content by weight)

3g/L (equivalent to 2g/L gold metal)

Note : Ensure that potassium gold cyanide is a high-purity grade without other additives.


Operating conditions

MID Au-89

Operating range

Optimal conditions


80-88 ℃

82 ℃

Gold content



Additive content




6-10 minutes

8 minutes

PH value ( 24 ℃ )




Solution maintenance and replenishment

1. Determination of gold concentration

Reagents: 1% v/v hydrochloric acid solution (used to prepare standard solution and working solution samples)

2mg/L gold standard solution

10mg/L gold standard solution


    1 .amount of 1 ml of the working solution into 500 mL volumetric flask (dilution factor 500 )

    2. Dilute to liquid level with 1% v/v hydrochloric acid solution

    3. Set the conditions for the determination of gold content in atomic absorption spectroscopy :




Gap width


Background correction


Blue flame



4. Absorption measurement 2mg/L gold standard solution

    5. Absorption measurement 10mg/L gold standard solution

    6. Absorb and measure the diluent and record the data

    Calculation: g/L gold content = (atomic absorption reading * dilution ratio) / 1000



1. Maintain the content of supplementary gold to control it at 1.5-2.5g/L

2. Each addition of 0.1485g/L of potassium gold cyanide can increase the gold content of 0.1g/L


2. Additive analysis

Reagent: concentrated ammonia

Ammonium violurate tablets or powder ( 1g ammonium violurate mixed with 100g sodium chloride)

0.115N EDTA standard solution (equivalent to 0.0575M )

Nickel standard solution ( 10g/L nickel metal)

1. Add 44.78 grams of nickel sulfate hexahydrate in a 1 liter volumetric flask and dilute to 1 liter with pure water . 

2. Analyze the solution to determine the exact nickel content. The nickel content of this solution is 9.8-10.2 g/L .

3. Adjust the nickel content in turn.



1. Measure 5 ml of working solution into an Erlenmeyer flask.

2. Add 50 ml of pure water.

3. Pipette 10 ml of nickel standard solution into an Erlenmeyer flask. (This step should ensure accuracy)

4. Add 10 ml of concentrated ammonia water.

5. Add 2 urethane ammonium tablets or a sufficient amount of powder to change the color of the solution to green / brown.

6. Use 0.115N EDTA standard solution to titrate to purple as the end point. (This titration should not exceed 29.7 ml)

    Calculation: The number of moles of free additives = ( 0.34 ) - [(Titration milliliters * EDTA concentration) / 10 ]



1. Maintain the additive content in the solution at 0.135M-0.165M .

2. Each supplement of 34ml/L of MID Au-89 can increase the additive concentration of 0.01M .


3. PH

1. Ensure that the pH value of the solution is maintained within the normal range.

2. If the pH value of the solution decreases, 50% ammonia water or ammonia water with a lower volume ratio can be used to increase the pH value.

3. If the pH of the solution increases, 20% by volume sulfuric acid can be used to lower the pH .

4. All addition adjustments must be added slowly under continuous solution movement.

5. After adding and adjusting, you must wait for the solution to mix for about 5 minutes before checking the pH value of the solution .

Remarks: Generally , there is no need to adjust the PH value after the bath is built , unless the PH operating range is exceeded .


Solution life

When the MID Au-89 working solution has passed 3 complete metal replenishment cycles or the nickel and palladium metal content in the solution exceeds 1000mg/L , one of the two needs to be replaced and a new solution needs to be prepared.


1. Q: Do you make the products yourself? Are you a trader or a manufacturer?

A: Yes, the products are produced by our company. Our company is a manufacturer focusing on the R&D and manufacturing of environmental protection electroplating additives. Our factory has 5000 square meters with an annual capacity of 15000 tons.

2. Q: Can your company send samples for trial?

A: We can provide samples for trial.

3. Q: What is the quality of your products?

A: Our company all products core raw materials is used by Germany BASF, American Dow Chemical and other international brand products. The production process is strictly in accordance with the ISO9001 quality management system, from the incoming inspection, product inspection, according to the strict inspection standard, ensure that every drop of products qualified. Product quality you can rest assured, like BYD, Huawei, Foxconn such enterprises are also using our products.

4. Q: How long is the shelf life of your products?

A: The shelf life of our products is two years. If you do not use up the products within a short time after you buy them, we suggest you store them in a cool place, not in the sun or in a high temperature environment.

5. Q: Are your products environmentally safe?

A: Our products have passed the SGS test and are recognized as "Green and Environment-friendly Promotion Products". Many auto parts and electronic products which use our products can pass the strict environmental protection test when they are exported to Europe and America. Therefore, we can be trusted in terms of environmental protection and safety.

6. Q: Can your company provide technical services?

A: Yes, our company has a technical service team of more than 10 people. The technical engineers all have more than 20 years' experience in electroplating factory. They can provide customers with comprehensive technical of pre-sales and after sales.

7. Q: Is it possible to visit your company?

A: Yes, of course. You are very welcome! We can meet you at Jieyang airport, If you can come to our city. Also you can visit our factory through live video.

8. Q: Can you customize products according to our needs?

A: Yes, our company has research and development strength, the product formula derived from Europe and the United States laboratory, European and American engineers technical support, work together with domestic universities. Our company has a member of Guangdong province expert enterprise workstation, Shantou university science and technology correspondent workstation, Jieyang city environmental protection engineering research center for electroplating additive.Therefore, it can meet all kinds of customized requirements proposed by customers.

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