Silver Plating Services
Mid-Atlantic’s silver plating services are performed on a state-of-the-art Silver Line with hoist systems in place. This Line allows us to offer our customers great flexibility in servicing their needs.
Our company has expertise in providing precision barrel and rack silver plating services and is currently employed in numerous industries including the medical, telecommunications, aerospace and electronics industries.
Silver Plating Process
Our silver plating service produces a white matte to very bright appearance. Silver provides good corrosion resistance depending on base metal but tarnishes easily. Silver possess excellent conductivity and lubricity and smear characteristics for anti galling uses on static seals, bushing, etc…Hardness varies from about 90 Brinnell to about 135 Brinnell depending on process and plating conditions. Solderability is excellent, but decreases with age.
Silver Plating Services To The Following Specifications:
The most common silver plating services certified are QQ-S-365, ASTM B700 and AMS 2410, AMS 2411 and AMS 2412. Mid-Atlantic Finishing can also certify our silver plating services to most company-specific silver plating specifications as shown in our. A summary of silver plating services per the MIL, ASTM and AMS specs is as follows:
|Type I:||Matte Deposits|
|Type II:||Semi-bright Deposits|
|Type III:||Bright Deposits|
|Grade A:||With Supplementary Tarnish Application (Chromates)|
|Grade B:||Without Supplementary Tarnish Application|
|Suitable Undercoat: The final silver deposit shall be preceded by an electrodeposited coating of silver from silver strike solutions. The plating shall be applied over an intermediate coating of nickel or nickel over copper on steel, zinc and zinc-base alloys. Copper and copper base alloys require intermediate coatings. Copper-alloy-basis metal articles on which a nickel undercoat is not used and other basis metal whereon a copper undercoat is employed shall not be used for continuous service at a temperature in excess of 149C (300F). Adhesion of the silver plating is adversely affected because of the formation by diffusion of a weak eutectic of silver and copper at the silver-copper interface.|
|Thickness of plating: Unless otherwise specified the minimum plating thickness shall be 0.0005 inch (0.013mm) on all surfaces on which silver is functionally necessary (for example: appearance, wear, corrosion protection, conductivity). The plating on nonfunctional surfaces and areas shall be of sufficient thickness to ensure plating continuity and uniform utility, appearance, and protection. On ferrous surfaces the total plated thickness shall be not less than 0.0010 inch (0.025mm). This must be comprised of at least 0.0005 inch (0.013mm) or more of silver plate over 0.0005 inch (0.013mm) or less of nickel or copper of any combination thickness of nickel and copper from 0 percent to 100 percent. The copper shall be deposited first over the steel surface.|
|Type 1:||99.9% Min Purity|
|Type 2:||99.0% Min Purity|
|Type 3:||98.0% Min Purity|
|Grade A:||Matte Deposits – Deposits without the use of brighteners|
|Grade B:||Bright Deposits – Deposits obtained with the use of brighteners|
|Grade C:||Bright Deposits – Deposits obtained by mechanical or chemical polishing of Grade A coatings|
|Grade D:||Semi-bright Deposits – Deposits obtained by the use of addition agents (grain refiners)|
|Class N||Without Supplementary Tarnish Application (Chromates)|
|Class S||With Supplementary Tarnish Application|
|Underplating: A nickel or nickel-alloy intermediate layer, at least 1um thick, shall be applied before the silver electroplate when the product being plated is made from copper or copper alloy. Nickel underplating is also applied for other reasons.|
|1. Parts shall be plated in the following sequence except as permitted below:|
|2. The nickel strike may be omitted when plating copper and copper alloys|
|3. A gold strike may be used in place of the silver strike when approved|
|When approved by the cognizant engineering organization, silver may be plated directly onto the substrate without the use of either the nickel or silver strike.
Except as specified herein, all parts, unless otherwise specified, shall be heated to 450F (232 C) after plating, rinsing and drying and held at heat for 60 minutes…
|Thickness –||Thickness of silver shall be as specified on the drawing. Where silver flash only is specified, plate thickness shall be approximately 0.0001 inch (2.5um)|
|Composition –||Silver as plated, shall be not less than 99.9% pure…|
The nickel strike shall be 0.0005 inch (13um) maximum. The use of organic base grain refining and brightener additives shall be prohibited in both the silver strike and silver plate solutions.
When approved by the cognizant engineering organization, an alternative to nickel strike is permitted.
Thickness of the deposit shall be as specified on the drawing…
- Nickel strike shall not exceed 0.0005 inch (13um)
- Where silver flash is specified, plate thickness shall be approximately 0.0001 inch (2.5um)
- Composition of the deposit shall be not less than 99.9% silver determined by a method acceptable to the cognizant engineering organization.
The copper strike may be omitted in plating copper and copper alloys, except for copper alloys containing zinc in quantities of 30% or more by weight.
A nickel flash shall be used before the copper strike when plating corrosion-resistant steels.
Parts, shall be heated to 300-500F (149 to 260C) after plating, rinsing, and drying and held for not less than two hours, unless such heating would lower hardness to below drawing limits or otherwise deleteriously affect the parts, in which case heating shall be at the highest practicable temperature which will maintain specified properties.
Thermal post treatment shall be in air, preferably in a circulating-air furnace.