MIL-STD-1276 Leads For Electronic Component PartsThis standard establishes the method of identifying, specifying, and limiting to a minimum the combinations of basic materials, the thickness and composition of the plating used therewith, and the sizes of wire and flat wire ribbon leads on electronic and electrical parts when they are to be soldered or welded during assembly in equipment.

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MIL-STD-1276H

5.2 Final finish. The final finish for leads (see 1.2.1.4) shall be homogeneous and conform to the following as applicable:

01 - No finish. Lead is supplied with no external finish.

21 - Gold plating, electrodeposited, in accordance with ASTM 8488 , type 2. The thickness of the gold plating shall be 100 to 300 microinches. When specified, under-plating shall be in accordance with

5.2.1.1.

22 - Gold plating, electrodeposited, in accordance with ASTM 8488 , type 2. The thickness of the gold plating shall be 50 to 100 microinches. When specified, under-plating shall be in accordance with

5.2.1.1.

32 - Tin-lead plating, electrodeposited, in accordance with SAE AMS-P-81728 . Composition shall be 50 to

70 percent tin (remainder lead). The thickness shall be 300 to 900 microinches (22.9 μm).

34 - Fused (reflowed) tin-lead plated, electrodeposited, in accordance with SAE AMS-P-81728 .

Composition shall be 50 to 70 percent tin (remainder lead). The tin-lead thickness after fusing (or reflow), shall not be less than 100 microinches (2.54 μm) at any single point. The average thickness of all points measured shall be 300 (7.62 μm) to 500 microinches (12.7 μm).

41 - Acid-tin-lead plating, electrodeposited, in accordance with ASTM 8545 . Thickness shall be 300 (7.62

μm) to 500 microinches (12.7 μm). Minimum lead content shall be 3 percent.

43 - Matte-tin-lead plating, electrodeposited, in accordance with ASTM 8545 . The thickness shall be 300 (7.62 μm) to 500 microinches (12.7 μm). The matte-tin plating shall contain no more than 0.05 percent by weight codeposited organic material measured as elemental carbon. Minimum lead content shall be 3 percent.

45 - Acid-tin-lead plating, electrodeposited, in accordance with ASTM 8545 . Thickness shall be 100 (2.54

μm) to 300 microinches (7.62 μm). Minimum lead content shall be 3 percent.

46 - Matte-tin-lead plating (low organic content), electrodeposited, in accordance with ASTM 8545 . The thickness shall be 100 (2.54 μm) to 300 microinches (7.62 μm). The matte-tin plating shall contain no more than 0.05 percent by weight codeposited organic material measured as elemental carbon. Minimum lead content shall be 3 percent.

51 - Hot solder dip. The composition shall be Sn60Pb40A, Sn63Pb37A, or Sn62Pb36Ag02C in accordance with J-STD-006 . The coating shall have a minimum thickness of 200 microinches as measured at the crest. Hot solder dip finish may be used over final finish types 21, 22, 32, 34, 41, 43,

45, 46, 61, 71, and 72. When specified (see 1.2.1.5), electroless nickel under-plating may be used in accordance with 5.2.1.3.

52 - Hot solder dip. The composition shall be Sn60Pb40A, Sn63Pb37A, or Sn62Pb36Ag02C in accordance with J-STD-006 . Thickness shall be 60-200 microinches as measured at the crest. Hot solder dip finish may be used over final finish types 21, 22, 32, 34, 41, 43, 45, 46, 61, 71, and 72. When specified (see 1.2.1.5), electroless nickel underplating may be used in accordance with 5.2.1.3.

61 - Nickel plating, electrodeposited, in accordance with SAE AMS-QQ-N-290 . Thickness shall be 50 (1.27

μm) to 150 microinches (3.81 μm). The nickel plating shall be nonbrightened and low stress.

71 - Silver plating, electrodeposited, in accordance with ASTM 8700 , grade D, class N. Thickness shall be

150 (3.81 μm) to 350 microinches (8.89 μm).