Silver plating intended for engineering purposes is usually employed for solderable surfaces, electrical contact characteristics, high electrical and thermal conductivity, thermocompression bonding, wear resistance of load-bearing surfaces, and spectral reflectivity.
Specification: QQ-S-365 Silver Plating, Electrodeposited (This spec has been cancelled, but is still in wide use.)
| [FONT=Times New Roman, Times, serif]Type-I[/FONT] | [FONT=Times New Roman, Times, serif]Matte finish[/FONT] |
| [FONT=Times New Roman, Times, serif]Type-II[/FONT] | [FONT=Times New Roman, Times, serif]Semi-Bright finish[/FONT] |
| [FONT=Times New Roman, Times, serif]Type-III[/FONT] | [FONT=Times New Roman, Times, serif]Bright finish[/FONT] |
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| [FONT=Times New Roman, Times, serif]Grade[/FONT] | [FONT=Times New Roman, Times, serif]A[/FONT] | [FONT=Times New Roman, Times, serif]With supplementary tarnish-resistant treatment (chromate treatment)[/FONT] |
| [FONT=Times New Roman, Times, serif]Grade[/FONT] | [FONT=Times New Roman, Times, serif]B[/FONT] | [FONT=Times New Roman, Times, serif]Without supplementary tarnish-resistant treatment[/FONT] |
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| [FONT=Times New Roman, Times, serif]Thickensses:[/FONT] | [FONT=Times New Roman, Times, serif]• 0.0003"[/FONT] | [FONT=Times New Roman, Times, serif]For articles such as terminals which are to be soldered[/FONT] |
| | [FONT=Times New Roman, Times, serif]• 0.0005"[/FONT] | [FONT=Times New Roman, Times, serif]For corrosion protection of nonferrous basis metals or for increasing the electrical conductivity of basis metals[/FONT] |
| | [FONT=Times New Roman, Times, serif]• 0.0050"-0.0100"[/FONT] | [FONT=Times New Roman, Times, serif]For electrical contacts, depending on pressure, friction and electrical load[/FONT] |
SPECS FOR RHODIUM
Here are the applicable specifications:
MIL-R-46085
MIL-R-46085
Copper in color and matte to a very shiny finish. Good corrosion resistance when used as undercoat. A number Of copper processes are available, each designed for a specific purpose. Brightness (to eliminate the need for buffing); High speed (for electroforming); Fine grain (to prevent case hardening); etc. Stress relief steel parts cold straightened or suspected of having residual tensile stresses having Rockwell hardness RC35 or higher will be subjected to 375° ±25°F-24 hours within 4 hours after plating. Parts with tensile strength over 120 Ksi bake 24 hours within 4 hours after plating.
Type Class Thickness Comments
Type I
Over nickel. silver, gold or platinum.
Type II
Over other metals, requires nickel undercoat.
Class 1 .000002" min Used on silver for tarnish resistance.
Class 2 .00001" min
Class 3 .00002" min Applications range from electronic to nose cones — wherever wear, corrosion resist solderability and reflectivity are important.
Class 4 .00010" min
Class 5 .00025" min