Electrolytic Plating Services » Tin/Lead Plating (Company) Services per MIL-P-81728 and ASTM B579

Tin/Lead Plating (Company) Services per MIL-P-81728 and ASTM B579

Advanced Plating Technologies is an industry leading company in exacting tin/lead plating services to MIL-P-81728 and ASTM B579.  Advanced Plating Technologies, a Milwaukee, Wisconsin company, offers a diverse portfolio of tin/lead plating services including 10/90, 90/10, 60/40 and 95/5 formulations. In addition, any custom tin/lead formulation can be produced upon request to meet any company specification.  Our expertise in providing precision barrel, rack and vibratory tin/lead plating services is currently employed in numerous industries including the bearing, railway, aerospace, defense, battery, electronic and fire protection industries.

Tin/lead plating services are utilized for unsurpassed solderability and in critical electrical and electronic applications eliminating the potential for tin whisker formation.  Whiskers can cause failure of electrical and electronic components by bridging multiple conductor paths causing a short circuit (reference:  Tin Whiskers: Failure Modes and Mitigation Strategies for a detailed NASA report within our Technical Library)

Advanced Plating Technologies specializes in demanding plate-to-gauge tin/lead plating and silver plating services for bearing, bushing and thrust washer applications in the aerospace, railway, defense and heavy mechanical industries.  Our dedicated Quality Control department provides preplate, in-process and post-plate dimensional and surface finish (Ra) inspections of inner and outer bearing surfaces to ensure dimensional and surface finish requirements are met.  Selective and heavy build tin/lead plating services have been provided up to 0.020 inches in thickness per side.

Tin Lead Plating Services – Tin Plating Properties

Tin/Lead Plating services, also referred to as solder plate or solder deposits, are functional finishes with a dull luster that can have a slightly mottled appearance.  Due to the matte nature of the deposits they are susceptible to rinsing stains and staining from handling.  If a bright appearance is desired, the surface can be overplated with a thin coating of bright tin or the deposit can be subsequently reflowed to a bright appearance.  At the present time, Advanced Plating Technologies does not offer reflow of tin/lead plating services in-house.

The ratio of tin to lead in tin/lead plating services affects the hardness and melting point of the deposit.  The eutectic ratio of 63/37 provides the lowest melting point of 361F of all the tin/lead plating ratios.  In tin/lead plating, the higher the tin composition of the deposit, the higher the abrasion resistance will be.  Tin/lead plating imparts excellent solderability to basis metals, minimizing the potential for tin whiskers or tin pests.

Tin/lead plating services on bearings are commonly used for break-in purposes on highly loaded bearing applications generally in the range of 3,000 to 8,000 PSI where the surface speed is relatively low.  Heavier coatings are used in loadings up to 3,000 PSI where the thicker coating allows for imbedability of contaminants, especially on grooved bearing designs.

Tin Lead Plating Services – Advanced Plating Technologies’ Capabilities

Most Company Specifications

Finish Type:
Any Alloy Composition Available from 95/5 to 5/95 Tin/Lead

Substrates Plated On:

Ferrous: All Ferrous Alloys Including Mild Steel, Stainless Steels, Hardened Steels & Tool Steels
Cuprous: All Cuprous Alloys Including Pure Copper, Copper Alloys Including Tellurium & Beryllium, Brass, Nickel-Silver
Aluminum: All Aluminum Alloys Including Wrought, Cast and Proprietary Alloys (MIC-6)
Exotics: Inconel, Pure Nickel (Nickel 200), Cobalt-Chrome (MP35N), Kovar, Monel, Hastalloy, Monel, Lead

Part Size Limitations: 20 Inches x 22 Inches x 8 Inches tin/lead plating services

Underplates Provided:
Electrolytic Nickel
Electroless Nickel

Heat Treatments:
Hydrogen Embrittlement Bakes
Stress Relieving Bakes

Selective Loose Piece Plating
Sheet Product (Chemically Milled/Etched Sheets)
Segmented Strips (Frets)

Tin Lead Plating Services – Tin Lead Plating Specifications

The two most common tin/lead plating services certified by Advanced Plating Technologies are MIL-P-81728 and ASTM B579.  APT can also certify tin/lead plating services to most company-specific tin/lead plating specifications.  A summary of tin/lead plating services per the MIL and ASTM specs is as follows:

Tin/Lead Plating Services to MIL-P-81728

Composition of the bath is specified as 50-70 w% Tin, 1.0 w% Max other metals and the remainder Lead.  Other compositions are permitted as specified under section 6.3.

3.2.5 Underplating – No underplating is specified except for alloys containing 15% or more zinc or beryllium.  A copper or nickel underplating of 0.0001 inch is recommended on such alloys.

3.2.8 Unless otherwise specified, either a matte or bright luster shall be acceptable.  For electronic components only a matte of flow brightened finish shall be furnished.

3.3.1 Thickness of Plating – Unless otherwise specified the thickness of the plating, except on electronic components, shall not be less the 0.0003 inches and shall not be greater than 0.0005 inches on visible surfaces that can be touched by a 0.75 inch sphere.

APT Note:  A 0.0003” minimum to 0.0005” maximum plating tolerance may not be realistic based upon the part geometry.  If this is the case, a finishing engineer will work to clarify the functional surface of the part where this range can be maintained.  Deviations will be noted on quotations as necessary. Thickness of Plating for Electronic Components – Unless otherwise specified the thickness for electronic components shall be a minimum average of 0.0003 inches where measured at four points at least 0.10 apart with no single reading being below 0.0002 inches.

tin/lead plating services Tin/Lead Plating Services to ASTM B579

The composition of the coating is 50-70 w% tin, with lead the remainder.

Suffix Notation:

F – flow brightened deposits
B – bright deposits (as plated)
M – Matte deposits

Classes of tin/lead plating services per ASTM B579 as follows:

Service Class       Application             Thickness (Steel)        Thickness (Copper)

SC 4                          Very Severe            30 um minimum          30 um minimum
SC 3                          Severe                       20 um minimum          15 um minimum
SC 2                          Moderate                 10 um minimum          8 um minimum

SC 1                          Mild                            5 um minimum            5 um minimum
Underplating of 0.0001” nickel or copper is required for alloys containing 15% or more zinc.