MIL-STD-868 Nickel Plating, Low Embrittlement, Electro-DepositionThis standard covers the process and materials required for the electro-deposition of nickel on high strength steel substrates. Electro-deposited nickel is used for wear resistance, heat resistance, and as an undercoat for precious metals. Subsequent heat treating techniques needed to insure low hydrogen embrittlement of steel are also described. This standard meets the performance requirements of SAE-AMS- QQ-N-290 and may be used when SAE-AMS-QQ-N-290 is specified provided any unique requirements of SAE-AMS-QQ-N-290 are complied with.

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MIL-STD-868B CHANGE 2

pH                                                      3 - 5

Temperature                                      38 - 60°C (100 - 140°F)

NOTE:  Additional anode corrosion aids and anti-pit aids may be used in accordance with the vendor's instructions.

5.3.5   Step 5.  Rinse all parts in cold water.

5.3.6   Step 6.   Rinse parts in hot water and blow dry with compressed air. Elapsed time between completion of plating and start of baking, Step 7, shall not exceed four (4) hours.

5.3.7   Step 7.   Bake all parts heat treated above 1240 MPa (180,000 psi) after plating for twenty-three (23) hours minimum, at 191 ± 14°C (375 ± 25°F).

5.4   Method 2.  The nickel plating procedure shall be as described below:

5.4.1   Step 1.   Parts shall be degreased as necessary.

5.4.2   Step 2.   Parts shall be dry blasted using 80 - 320 grit aluminum oxide (AI2

03), silicon dioxide (Si02), or garnet per MIL-STD-1504.

5.4.3   Step 3.  Anodic etch in the following solution or a proprietary equivalent at

3 to 6 volts for ninety (90) seconds or in accordance with the vendor's recommendations.

Sodium Hydroxide                              3.8 - 11.2 g/l (0.5 - 1.5 oz/gal) Sodium Phosphate                             30 - 90 g/l (4.0 - 12.0 oz/gal) Sodium Carbonate                             7.5 - 45 g/l (1.0 - 6.0 oz/gal) Temperature                                      52 - 58°C (125 - 135°F)

5.4.4   Step 4.  Rinse all parts in cold water.

5.4.5   Step 5.  Acid dip - sulfuric acid concentrate (approximately 93% by weight acid) diluted to 10 - 20 percent by volume or a proprietary acid mix at room temperature for fifteen (15) to thirty (30) seconds or in accordance with the vendor's instructions.

5.4.5.1    Alternate Step 5.   The following sulfuric-hydrofluoric acid solution may be used on high silicon alloys such as 300M.  It may also be applicable to other difficult to plate alloys.

a.    Sulfuric acid concentrate (approximately 93% by weight acid) diluted to 22 to 30% volume.

total fluoride.

b.   Hydrofluoric acid or ammonium bifluoride - 3.0 to 6.0 oz per gallon as

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