MAR MN-66 is a post-etch back neutralizer solution designed to neutralize and clean permanganate residue from the holes of printed circuit boards. It insures a well-conditioned hole wall surface that allows for subsequent electroless copper coverage.

When used with GE-70, a mild glass frost to glass etch will occur.

Advantages of the MAR MN-66 process include:

  • Excellent Neutralization - Improved hole quality
  • Chloride\Peroxide Free - Extended Solution Life
  • Low Copper Build-up - Reduced Copper Attack
  • Low Copper Build-up - Reduced Copper Attack
SOLUTION MAKE-UP (100 litre solution)
Water 84 litres
MAR MN-66 10 litres
Sulphuric acid 6 litres

NOTE: The make-up of this solution must be done in the stated above order.


MAR-Tech recommends that the MN-66 bath be replaced when the concentration of copper metal reaches 1,500ppm in the made up solution.

Optimum Range
MAR MN-66 100 ml/litre 80 – 120 ml/litre
Sulphuric acid 6% BV 4 - 7% BV
Temperature 43ºC 40 - 46ºC
Time 5 mins. 4 – 6 minutes
  1. Reagents Required
    1. Saturated Ferric Ammonium Sulfate Solution (198g/L in 1% v/v Sulfuric Acid)
    2. 0.1 Normal Potassium Permanganate Solution
    3. 50% v/v Sulphuric acid (98%)
    4. 85% phosphoric acid
  2. Method
    1. Pipet 2 ml of the working solution into a 250 ml Erlenmeyer Flask and dilute to 30 ml with de- ionized water.
    2. Add 5 ml of the Ferric Ammonium Sulfate Solution and 5 ml of the sulfuric acid solution.
    3. Boil on a hot plate for 5 minutes, remove and cool. Dilute to 150 ml with de-ionized water.
    4. Add 5 ml of phosphoric acid and mix.
    5. Titrate with 0.1 Normal Potassium Permanganate to a pink endpoint lasting 15 seconds or more.
  3. Calculation

    ml/litre MAR MN-66 = (ml KMn04) x (Normality of KMn04) x 80

    Maintain concentration of MAR MN-66 between 80 to 110 ml/litre

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