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

c. Operate at 60° to 75°F, 3 to 6 amps per square inch anodic for 45 to 90 seconds.

d. This etch should leave an adherent dark gray to black film. If these conditions are not met the process must be stopped and the part baked per paragraph

5.4.10.

5.4.6 Step 6. Rinse parts thoroughly in cold water.

5.4.7 Step 7. Nickel plate in nickel plating solution (paragraph 5.3.4) to required thickness.

5.4.8 Step 8. Rinse parts in cold water.

5.4.9 Step 9. Rinse part in hot water and blow dry with compressed air. Elapsed time between completion of plating and start of baking, Step 10, shall not exceed four (4) hours.

5.4.10 Step 10. 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).

5.5 Inspection. Inspection shall be in accordance with the production control inspection and tests in SAE-AMS-QQ-N-290 and this standard.

5.6 Process controls. Solutions and equipment used in the plating process shall be checked periodically and maintained in accordance with the requirements of this process standard.

5.7 Qualification embrittlement test. The processor shall demonstrate the ability to provide nickel plating which meets the requirements of paragraph 4.5 of this standard as follows:

a. Four round notched 4340 steel specimens per ASTM F519, Type 1a.1 or 1a.2 shall be prepared.

b. The specimens shall be prepared for plating and plated in accordance with all of the requirements of this specification. During plating the specimens shall be mounted symmetrically on a rack by themselves. All areas of the rack except the contact area shall be coated with a suitable maskant. An ammeter, having a sensitivity of 0.5 amperes or better shall be connected in the plating circuit near the specimens being plated. The ammeter shall either be built into the rectifier being used or shall be inserted between the rectifier and the cathode. The specimen shall be plated at 4.8 amperes per square decimeter (45 amps per square foot) to a minimum of

0.05mm (0.002 inches) thick. The specimen shall be baked for twenty-three (23) hours at 191°± 14°C (375°± 25°F) within four hours of removal from the bath.