Chapter 1.11

Miscellaneous Plating Solutions

 

Copper Displacement Plating Solution (W. G. Oldham)

►          50 ml Al2O3

        50 ml CuCl

        50 ml CuSO4

        50 ml HF

        500 ml H2O

Plate one minute. (Pits silicon but removes Al2O3.)                                         

Gold Electroplating using E-55 Engelhard Salts

►                Clean surface well before plating.  Combine:

4 g salts

100 ml DI H2O

Warm to dissolve.

Add 1.63 g E-55 gold cyanide.

Use stainless steel anode. Warm to 150ºC.  Current density: 35 Ma/in2. Plating rate at above current: 0.0001"/7min.

Nickel Plating (Electrodeless) for Ohmic Contacts (W. G. Oldham)

JECS 1957, p 226.

►          Nickel Chloride                    30 g/L

        Sodium Hypophosphite        30 g/L

        Ammonium Citrate               65 g/L

        Ammonium Chloride            50 g/L

Filter solution. Warm to 90ºC. Give sample aluminum wand treatment. Ad NH4OH until solution turns from green to blue (pH 8-10).

Nickel Plating of Brass (Wheeler)

►           Start with clean degreased (trichlor) surface. Plating will only be as good and shiny as original surface. Dip and etch in clean acid* and bright acid** for less than 1 minute (until bubbles appear).  Wash well with DI water and carry to plating solution*** wet. Plating rate:  ~1 mil/10  min.  For brightest surface, buff with rough afterwards.

 * Wheeler's Clean Dip

H2SO4        136 oz

HNO3        26 oz

HCl           2 oz

Water        Sufficient to bring volume to 1 gal.

 ** Wheeler's Bright Dip

H2SO4 : HNO32  1 : 1

Mix in ice bath

 *** Nickel Plating Solution

Nickel ammonium sulfate        8 oz

Nickel sulfate                         4 oz

Boric acid                              2 oz

Sodium chloride                     2 oz

Water                                   Sufficient to bring volume to 1 gal.

PH                                       5.8

Voltage                                 21.5 V

Current Density                      6.8 amp/ft

Anode                                  Pure nickel

Anode/Cathode ratio               1.1 : 1

 *** White's Nickel Plating Solution

Ni Stock

NiSO4                                   350 g dissolved in one liter water

H3BO3                                   32.2 g

NaCl                                    13.4 g

Sodium lauryl sulfate              0.4 g

H2SO4 conc.                           17.5 ml

Heat if necessary to dissolve.  Adjust pH to 3 with pH stock.

pH Stock

40 g NaOH

300 ml DI water

Plating Solution

Pure Ni Stock                                           200 ml

CoCl  (0.74M) (1.8g/10ml)                           1.5 ml

Sodium salt of naphthalene disolfonic

      acid (2.7M) (11.8 g to 150 ml DI water)      8 drops

Plating

Current density       20 mA/in2

Plating rate         1000 Å/min.

4/90 – K. Voros

Rev. 01 – 12/06, K. Voros