| Specification & Callouts | Description | Required Testing |
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MIL-C-14550 Copper Plating Class 0 Class 1 Class 2 Class 3 Class 4 |
thickness 1 to 5 mils thickness 1 mil minimum thickness 50 µin minimum thickness 20 µin minimum thickness 10 µin minimum |
MIL-C-14550 is the granddaddy copper plating spec. In typical mil spec fashion, the lower Class numbers indicate the thicker plating. MIL-C-14550 Class 0/1 are similar specifications with Class 0 having a maximum thickness. The minimum plate thickness is MIL-C-14550 Class 4 at 10 µin, which hardly qualifies as a flash. Although MIL-C-14550B has been superseded by AMS2418, the older mil spec is still worth reading. Bath Testing no bath parameters or tests mentioned in specification Coupon Testing - periodic ¶ 4.3.2: thickness ¶ 4.3.2: adhesion ¶ 4.3.2: embrittlement ¶ 4.3.2: solderability Coupon/Part Testing - per lot ¶ 4.3.1: coating thickness ¶ 4.3.1: visual |
| AMS2418 Copper Plating Type 1 Type 2 |
engineering plating plating for masking thickness 50-70 µin |
AMS2418G is the latest revision. As always, if you are certifying specification compliance you should purchase and understand the latest specification revision. Note that AMS2418 Type 1 and AMS2418 Type 2 have subtle differences in test requirements, so you should fully specify and understand what you are specifying. This is especially true with AMS2418, since there are some unique requirements buried within. For example, plating thickness is buried in the specification; however, this is routinely overridden by print or purchase order. Other unique requirements include restrictions on reworking parts and underplating. Although some external specifications are referenced, there are helpful guidelines and additional requirements for hydrogen embrittlement and solderability tests. The specification includes a sampling plan for acceptance tests; however, it is unclear whether this is a C=0 plan or an AQL plan. C=0 is the safe assumption. Bath Testing ¶ 4.2.2: processor to specify frequency and analysis methods and establish periodic test plan Coupon Testing - periodic ¶ 3.4.4: embrittlement ¶ 3.4.5: solderability Coupon/Part Testing - per lot ¶ 3.4.1: coating thickness ¶ 3.4.2: porosity ¶ 3.4.3: adhesion |
| ASTM B734 Copper Plating -X -5 -12 -20 -25 |
thickness specified on print minimum 5 µm (197 µin) minimum 12 µm (473 µin) minimum 20 µm (788 µin) minimum 25 µm (985 µin) |
ASTM B734-97(2008) is the current revision. Bath Testing no bath parameters or tests mentioned in specification Coupon Testing - periodic sampling plan may require ¶ 8.2: coating thickness ¶ 8.3: adhesion ¶ 8.3: porosity ¶ 8.5: solderability Coupon/Part Testing - per lot sampling plan may require ¶ 8.2: coating thickness ¶ 8.3: adhesion ¶ 8.3: porosity ¶ 8.5: solderability |
| AMS2402 Zinc Plating -1 -2 -3 -4 -5 -6 -X |
100 - 300 µin 200 - 400 µin 300 - 500 µin 400 - 600 µin 500 - 700 µin 600 - 800 µin X - X+200 µin if dash unspecified thickness must be dimensioned on print |
The current revision is AMS2402J and is available from SAE International. Bath Testing no bath parameters or tests mentioned in specification Coupon Testing - periodic ¶ 3.4.2: adhesion bend test ¶ 3.4.3: corrosion resistance Coupon/Part Testing - per lot ¶ 3.4.1: coating thickness |
| ASTM B633 Zinc Plating on Iron & Steel SC 1 SC 2 SC 3 SC 4 Type I Type II Type III Type IV Type V Type VI |
minimum 5 µm minimum 8 µm minimum 12 µm minimum 25 µm As-plated With colored chromate With colorless chromate With phosphate conversion With colorless passivation With colored passivation |
ASTM B633 describes zinc plating on iron and steel. ASTM B633-07 is the current revision. This is a specification that references many other ASTM specifications and really doesn’t spell out much in the way of requirements. Tests and test methods are specified, but its up to the purchaser and supplier to determine whether these tests are to be done lot by lot, monthly, yearly or never. A purchaser who is asking for conformance to ASTM B633 should clearly define and document a test plan with the supplier to define acceptance criteria for each lot and the frequency at which process control tests should be performed. Note that the specification reference is critical to defining the required test procedures. For example, ASTM B633 Type I and ASTM B633 Type IV require no salt spray testing, while ASTM B633 Type II, ASTM B633 Type III, ASTM B633 Type V and ASTM B633 Type VI all require salt spray testing. The ASTM B633 Service Classes (e.g. ASTM B633 SC4) determine plating thickness as well as test requirements, so these SC designations should be used with or without specific thickness callouts added for clarity. Bath Testing no bath parameters or tests mentioned in specification Coupon Testing - periodic ¶ 10.3: corrosion resistance ¶ 10.4: hydrogen embrittlement Coupon/Part Testing - per lot ¶ 10.1: coating thickness ¶ 10.2: adhesion ¶ 10.5: visual |
| ASTM B456 Chrome/Nickel & Chrome/Nickel/Copper on Iron, Steel, Copper & Zinc SC 1 SC 2 SC 3 SC 4 SC 5 |
mild service moderate service severe service very severe service extended severe service |
ASTM B456 describes chrome/nickel and chrome/nickel/copper multi-layer plating on iron, steel, copper and zinc alloyed basis materials. ASTM B456-03 is the current revision. The plating thicknesses and deposit types vary depending on the plating, basis material and service condition. The spec defines a syntax for describing the plating; for example, Fe/Ni35d Cr mc describes a duplex nickel underplate with a micro-cracked chromium outer plate. You will definitely need the specification, and a PhD in table reading, to figure out how to specify what you want or to figure out what has been specified. Moreover, your plating supplier must conform to a number of specifications for elongation, ductility and sulfur content and will need to properly select chemistries and control bath parameters; although the specification does not mention any bath control requirements. We would recommend acid copper underplate, sulfamate nickel for the bottom layer of the duplex or triplex nickel, and Watts nickel for the middle and outer nickel layers. Does your plater have both types of nickel baths? This is a tough specification, and you don’t want premature corrosion in the field to be your first indication of non-conformance. A purchaser who is asking for conformance to ASTM B456 should clearly define and document a test plan with the supplier to define acceptance criteria for each lot and the frequency at which process control tests should be performed. Bath Testing no bath parameters or tests mentioned in specification Destructive Testing - periodic ¶ 6.4: elongation ¶ 6.5: ductility ¶ 6.7: corrosion resistance salt spray requirements listed by SC ¶ 6.8: intra-layer potential ¶ 6.9: sulfur content ¶ 6.10: chromium discontinuities Coupon/Part Testing - per lot ¶ 6.2: coating thickness ¶ 6.3: adhesion ¶ 10.5: visual |
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FED QQ-C-320 Chrome Plating Type I Type II Class 1 Class 2 Class 2a Class 2b Class 2c Class 2d Class 2e |
Bright finish Satin finish Corrosion protective Engineering plating Processed to print dimensions <RC40 not requiring shot peening <RC40 requiring shot peening >RC40 requiring embrittlement bake >RC40 requiring peening and baking |
QQ-C-320 is still referenced on many prints and certificates of conformance are still offered by many plating shops. Although FED QQ-C-320B was cancelled and superseded by AMS2460, it is still worthwhile keeping it handy. QQ-C-320 Class 1 is for corrosion protection while QQ-C-320 Class 2 is engineering plating. Although it is not exactly clear why corrosion resistance is not an engineering requirement, the specification calls completely different test requirements for the two classes. QQ-C-320B Class 1/2 can be specified as fully bright (Type I) or satin finish (Type II). There are some interesting prep, underplating and plating instructions toward the end of the specification. Bath Testing ¶ 4.3.1: processor to maintain bath records showing analysis results and chemical additions Coupon Testing - monthly ¶ 3.4.2.3: hardness ¶ 3.4.2.4: porosity ¶ 3.2.6: embrittlement Coupon/Part Testing - per lot ¶ 3.4.1.1: thickness ¶ 3.4.1.3: adhesion |
| AMS2460 Chrome Plating AMS2460 Type I, Class 1 AMS2460 Type I, Class 2 AMS2460 Type II, Class 1 AMS2460 Type II, Class 2 |
Bright finish, corrosion protective Bright finish, engineering plating Satin finish, corrosion protective Satin finish, engineering plating |
AMS2460 was released in 2007 with no revision letter. (That would be a document control finding at a Nadcap audit.) AMS2460 is the successor to the QQ-C-320 specification. There are a few additions, like disallowing add plate procedures, so if you plan to certify to the spec you should read it carefully. Bath Testing ¶ 4.2.2.1: processor to maintain bath records showing analysis results and chemical additions Coupon Testing - monthly ¶ 3.4.1: thickness ¶ 3.4.2: adhesion ¶ 3.4.3: hardness ¶ 3.4.4: porosity ¶ 3.4.5: embrittlement Coupon/Part Testing - per lot ¶ 3.4.1: thickness ¶ 3.4.2: adhesion ¶ 3.5: general quality |
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MIL-P-81728 Tin-Lead Plating |
MIL-P-81728 specifies procedures and uses for electrodeposited tin-lead plating. MIL-P-81728A is the latest specification. Bath Testing no bath parameters or tests mentioned in specification Coupon Testing - periodic ¶ 4.5.1: composition ¶ 4.5.4: porosity ¶ 4.5.6: embrittlement Coupon/Part Testing - per lot ¶ 4.5.2: thickness ¶ 4.5.3: adhesion ¶ 4.5.5: solderabililty |
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MIL-T-10727 Tin Plating Type I Type II |
Electrodeposited Hot Dipped |
MIL-T-10727 is the granddaddy specification for tin plating covering both electroplated and hot-dipped tin. MIL-T-10727C has been superseded, but the old spec is still worth reading. MIL-T-10727 Type I is electroplated tin, while MIL-T-10727 Type II is hot dipped. Bath Testing no bath parameters or tests mentioned in specification Coupon Testing - periodic ¶ 4.6.4: salt spray test Coupon/Part Testing - per lot ¶ 4.4.2.1: visual ¶ 4.6.1: coating thickness ¶ 4.6.2: adhesion ¶ 4.6.3: solderabililty |
| AMS2408 Tin Plating -flash -1 -2 -3 -4 -5 -6 -X |
~100 µin 100 - 300 µin 200 - 400 µin 300 - 500 µin 400 - 600 µin 500 - 700 µin 600 - 800 µin X - X+200 µin if dash unspecified thickness must be dimensioned on print |
AMS2408 describes tin plating on various basis materials. The current revision is AMS2408J and is available from SAE International. Bath Testing ¶ 4.2.2: periodic tests of cleaning and plating solutions to ensure results Coupon Testing - periodic ¶ 3.4.2: adhesion Coupon/Part Testing - per lot ¶ 3.4.1: coating thickness ¶ 3.4.2: adhesion ¶ 3.4.3: solderability if req’d |
| AMS2409 Tin Plating Immersion |
100 µin unless other thickness is dimensioned on print |
AMS2409 describes tin plating on various basis materials using a dipped processes (not electroplated). The current revision is AMS2409G and is available from SAE International. Bath Testing ¶ 3.2: concentration of tin stannate, pH and temperature Coupon Testing - periodic ¶ 3.5.1: coating thickness ¶ 3.5.2: adhesion Coupon/Part Testing - per lot ¶ 3.5.3: general quality |
| ASTM B545 Tin Plating Electrodeposited Class A Class B Class C Class D Class E Class F |
thickness 100µin thickness 200µin thickness 320µin thickness 400µin for steel thickness 600µin thickness 800µin for steel thickness 1.2 mil thickness 60µin |
ASTM B545 describes electrolytic tin plating on various basis materials. The thickness callouts are inexplicable, until you realize that ASTM B545 Class F is a "Flash" - never mind that many people are likely to think that ASTM B545 Class F should be a thicker plate than ASTM B545 Class E or ASTM B545 Class A. ASTM B545-97 is the current revision which was reissued in 2004. Bath Testing no bath testing is specified Coupon Testing - periodic ¶ 8.1: deposit purity ¶ 8.5: porosity Coupon/Part Testing - per lot ¶ 8.2.1: thickness ¶ 8.3: adhesion ¶ 8.4: solderability |
| AMS2416 Nickel-Cadmium Diffused -X |
X to X+200 µin NICKEL nickel thickness 200-400 µin if not specified by dash cadmium thickness 100-300 µin and may not be changed conversion coat or dye may be specified on print |
AMS2416L is available from SAE International. AMS2416 is targeting high-temperature, corrosive environments. Beware of regulations banning the use of Cadmium. As always, the supplier should purchase and follow the specification. AMS2416 contains helpful instructions and specific requirements for plate thickness and heat treatments required to achieve proper diffusion. Bath Testing ¶ 4.2.2: periodic testing of cleaning and plating solutions to ensure specification conformance Coupon Testing - periodic ¶ 3.3.2: heat resistance ¶ 3.3.3: corrosion resistance ¶ 3.3.4: nickel stress test Coupon/Part Testing - per lot ¶ 3.3.1: nickel thickness ¶ 3.4: general quality |
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FED QQ-P-416 Cadmium Plating Type I Type II Type III Class 1 Class 2 Class 3 |
As plated Chromate treatment Phosphate treatment 50 µin minimum thickness 30 µin minimum thickness 20 µin minimum thickness |
FED QQ-P-416 seems to be active at QQ-P-416F, although AMS QQ-P-416 has been referenced as superseding. SAE International does not show AMS QQ-P-416 as available. QQ-P-416 Type I gets no post plate treatment; QQ-P-416 Type II gets a post-plate chromate conversion treatment; and QQ-P-416 Type III gets a post-plate phosphate treatment. Print notes should reference the thickness Class, even if a specific thickness is also specified, since the detailed plating requirements are a function of the Class callout. Bath Testing ¶ 4.4.1: processor to maintain bath records showing analysis results and chemical additions Coupon Testing - monthly ¶ 4.5.1: plating adhesion ¶ 4.5.2: corrosion resistance ¶ 4.5.3: embrittlement Coupon/Part Testing - per lot ¶ 4.4.2.2.1: visual inspection ¶ 4.4.2.2.2: coating thickness |
| AMS2400 Cadmium Plating -flash -1 -2 -3 -4 -5 -6 -X no dash |
~100 µin no salt spray requirements when flash is specified 100 - 300 µin plate thickness 200 - 400 µin plate thickness 300 - 500 µin plate thickness 400 - 600 µin plate thickness 500 - 700 µin plate thickness 600 - 800 µin plate thickness X - X+200 µin plate thickness 100-400 µin plate thickness |
AMS2400W is available from SAE International. AMS2400 is targeting corrosive environments. Beware of regulations banning the use of Cadmium. As always, the supplier should purchase and follow the specification. AMS2400 contains restrictions on underplating and requires compliance with some unusual test specifications. Bath Testing ¶ 4.4.2: processor to specify frequency and analysis methods and establish periodic test plan Coupon Testing - periodic ¶ 3.4.3: corrosion resistance ¶ 3.4.4: embrittlement Coupon/Part Testing - per lot ¶ 3.4.1: coating thickness ¶ 3.4.2: adhesion |