MIL-STD-868-SUP-1 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.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14

MIL-STD-868B CHANGE I

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.

c.    The specimens will be subjected to 200 hours of static loading at 75 percent of the ultimate notched tensile strength.  The test shall be considered passed if all four (4) specimens meet the requirement of paragraph 4.5.

d.   Upon successful completion of the static load test one of the notched tensile  specimens  shall  be  sectioned  across  the  notch  parallel  to  the  axis  of  the

7