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SOURIAU PA&E offers customers a complete solution to meet their metal surface finishing needs.
Chromate Conversion - MIL-C-5541
In the chromate conversion process, the metal surface of a part is converted to a superficial layer containing a complex mixture of chromium compounds. The chromate film is soft when freshly formed, but once dried and aged, the film becomes more abrasive resistant. Chromate conversion coatings provide excellent corrosion resistance.
Electroless Nickel - AMS-C-26074, AMS-2404
Electroless nickel describes the plating of nickel deposits, which may contain phosphorus and boron, onto catalytic metallic or catalyzed non-metallic substrates by chemical reduction. Unlike electrolytic plated nickel coatings, electroless nickel coatings produce very uniform, hard, and lubricious coatings, without an externally applied electric current, and are normally identified according to their phosphorus content.
| Plating Specification* |
Notes |
Thickness** |
| AMS-2404, Class 1 Electroless Nickel |
Electroless nickel is Enova 583. Mid-phos content of 4-8% |
+/-50 microinches, minimum of 25 microinches, maximum 1000 microinches |
| AMS-2404, Class 4 Electroless Nickel |
| AMS-C-26074, Class 1, Grade A & B Electroless Nickel |
| AMS-C-26074, Class 4, Grade A & B Electroless Nickel |
| ASTM-B-733, Class 1, Type 1 & 4 only |
| ASTM-B-733, Class IV, Type 1 & 4 only |
Electrolytic Gold - ASTM-B-488 and MIL-DTL-45204
Electrolytic gold offers high electrical conductivity, solder-ability, weld-ability, infrared-reflectivity, and excellent corrosion resistance (as well as sealing the nickel surface to eliminate passivation). Electrolytic gold is primarily used in the electrical industry for RF connectors and printed circuits, and in the electronics industry for transistor integrated circuits.
| Plating Specification |
Thickness** |
| ASTM-B-488, Type I, Code C (Hard Gold) |
+/-25 microinches, minimum of 25 microinches, maximum 250 microinches |
| ASTM-B-488, Type III, Code A (Soft Gold) |
| MIL-DTL-45204, Type I, Grade C (Hard Gold) |
| MIL-DTL-45204, Type I, Grade A (Soft Gold) |
Electrolytic Nickel - QQ-N-290 and AMS 2403
Unlike electroless nickel, electrolytic nickel uses an external current supply to plate the nickel to various substrates. It is one of the most widely used types of plating due to fact it can be welded unlike electroless nickel. Electrolytic nickel comes in different forms, and is one of the most popular being sulfamate nickel, which has a dull, matte finish, and is often used as an undercoating for gold applications.
| Plating Specification* |
Notes |
Thickness** |
| AMS-QQ-N-290, Class 1, Electrolytic Nickel, Grades E, F, G |
Use of other grades possible depending on geometry and base metal |
+/-50 microinches, minimum of 25 microinches, maximum 400 microinches |
| AMS-QQ-N-290, Class 2, Electrolytic Nickel, Grades E, F, G |
| AMS-2403 Electrolytic Nickel |
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*Grade callouts on the nickel specifications are for thickness. SOURIAU PA&E generally calls out its own thickness ranges.
**Thickness ranges are best case, these can be effected by geometry and base metal. Painting - BMS 10-11, BMS 10-20, BMS 10-60
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