PCB plating process control

- Aug 28, 2018-

F.Analysis of sulfamate nickel plating solution

A. Determination of nickel content.See the analysis of modified watt nickel solution.

B. Determination of bromide content.See the analysis of modified watt nickel solution.

C. Determination of boric acid content.See the analysis of modified watt nickel solution.

G.Analysis of acid brightening tin solution

A. Determination of tin content.See a section for determination of tin content in tin - lead plating solution

B. Determination of sulfuric acid content.The following reagents are required:

1) 1 equivalent concentration of NaOH (40.0g/l).

2) 4% ammonium oxalate.Dissolve 4 grams of ammonium oxalate in 96 milliliters of distilled water.

3) methyl red indicator.Dissolve 1 g of methyl red indicator powder in 50 ml of isopropanol and 50 ml of distilled water.

Analysis methods:

1) take 5 ml solution from pipette and put it into a 250 ml conical flask.

2) add 50ml 4% ammonium oxalate solution.

3) add 20 drops of methyl red indicator.

4) titrate with 1 equivalent NaOH until the color turns yellow.

Calculation:

1 ml of 1 equivalent concentration of NaOH=0.0490 g/l H2SO4

Milliliter of 1 equivalent concentration of NaOH times 9.8= g/l H2SO4

One milliliter of an equivalent concentration of NaOH times 1.31= ounce/gallon H2SO4