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Tin Plating

Electroplating & electroless plating · Electrolytic bath

Tin plating is a soft, solderable electrodeposit for copper-alloy and steel electrical parts.

CNC machiningSheet metalStandard cost $$Conductive
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Tin Plating on a machined part

What is Tin plate?

ASTM B545 defines service classes and minimum thickness.

How it works

Clean, activated parts are cathodically plated from an acid or alkaline tin electrolyte, usually with a nickel or copper underplate where diffusion or adhesion requires it. Matte tin minimizes organic brightener and is generally preferred where whisker controls matter. Fusing or reflow can change grain structure. As an electrolytic process, tin builds at edges and can be thin in deep recesses.

Why specify it

  • Good solderability at 3–15 µm typical thickness
  • Low contact resistance for separable low-force contacts
  • RoHS-compatible pure tin options
  • Protects copper from oxidation during storage

Where it falls short

  • Pure tin can grow whiskers
  • Fretting corrosion affects mating contacts
  • Soft deposit scratches and cold-flows
  • Steel needs underplate and corrosion design

Tin plate at a glance

Tin plate is a middle-of-the-range finish; its best score is cosmetic quality (45 of 100), at a standard cost. It adds little surface hardness.

Corrosion protectionLow34 / 100
Surface hardnessMinimal0 / 100
Cosmetic qualityFair45 / 100
LubricityFair38 / 100
Relative costStandard20 / 100
CorrosionHardnessCosmeticLubricityEconomy

Each score is 0–100 against every finish in this catalog. Corrosion comes from salt-spray life (ASTM B117, log scale) and hardness from the finish layer's Vickers or pencil hardness; cosmetic, lubricity and cost are FabDigit's engineering assessment. Economy on the radar is the inverse of cost.

Tin plate key numbers

Typical values from the governing specifications and shop practice; bars are this finish against the highest value among electroplating & electroless plating finishes.

Thickness3–15 µm0.12–0.59 mil
Hardness5–20 HV
Salt spray24–48 h
Max service temp.150 °C302 °F
Thickness
3–8 µm for solderability; 8–15 µm for heavier service or diffusion margin
Hardness
5–20 HV — Tin is very soft; values vary with deposit and test method.
Corrosion (salt spray)
24–48 h per ASTM B117 to red rust on steel, 5–10 µm (typical) — Tin is cathodic to steel, so pores rust early; specified for solderability, not as a barrier.
Electrical
Conductive
Colours
  • silver
Appearance
Matte white-gray or bright silver-white.

Where Tin plate sits among all finishes

Surface hardness (Vickers, log scale) against corrosion protection (salt-spray hours, log scale) for every coating FabDigit offers, one cloud per finish group. Tin plate is highlighted; hover a dot for its name or open the full map.

02550751000255075100Corrosion protection (0–100)Surface hardness (HV, log scale, 0–100)Plating — 19 finishesHard coatings — 17 finishesAnodize & conversion — 8 finishesPaint & powder — 7 finisheshard, low corrosion protectionhard and protectiveprotective, softsoft, little protectionType II anodize — corrosion 71, hardness 54BSA anodize — corrosion 71, hardness 52Type I anodize — corrosion 71, hardness 49Hard anodize — corrosion 71, hardness 61PTFE hard anodize — corrosion 71, hardness 61Nitriding — corrosion 55, hardness 73PEO — corrosion 70, hardness 74Sherardizing — corrosion 83, hardness 56Brass plate — corrosion 35, hardness 44Bronze plate — corrosion 40, hardness 49Cadmium plate — corrosion 70, hardness 26Copper plate — corrosion 32, hardness 39Decorative chrome — corrosion 64, hardness 71Electroless copper — corrosion 20, hardness 41Electroless nickel — corrosion 70, hardness 68Nickel plate — corrosion 51, hardness 55Gold plate — corrosion 68, hardness 39Hard chrome — corrosion 40, hardness 73Hot-dip zinc — corrosion 90, hardness 42Nickel-PTFE — corrosion 72, hardness 57Silver plate — corrosion 55, hardness 39Solder plate — corrosion 42, hardness 9Zinc plate — corrosion 60, hardness 30Zinc-nickel — corrosion 86, hardness 60Cerakote — corrosion 83, hardness 27E-coat — corrosion 83, hardness 15Epoxy coat — corrosion 83, hardness 15Powder coat — corrosion 83, hardness 14Wet paint — corrosion 59, hardness 10AlCrN PVD — corrosion 58, hardness 93AlTiN PVD — corrosion 52, hardness 94CrN PVD — corrosion 62, hardness 83DLC — corrosion 55, hardness 93MoS2 PVD — corrosion 20, hardness 26TiAlN PVD — corrosion 50, hardness 93TiCN PVD — corrosion 40, hardness 92TiB2 PVD — corrosion 40, hardness 94TiN PVD — corrosion 45, hardness 87WC/C PVD — corrosion 48, hardness 77ZrN PVD — corrosion 52, hardness 90CVD alumina — corrosion 70, hardness 85CVD TiCN — corrosion 38, hardness 92CVD TiN — corrosion 45, hardness 87Multilayer CVD — corrosion 62, hardness 88HVOF coating — corrosion 78, hardness 77Plasma spray — corrosion 60, hardness 68Plastic chrome — corrosion 72, hardness 71Electroless plastic — corrosion 58, hardness 39Clear coat — corrosion 20, hardness 12Soft-touch — corrosion 20, hardness 5PLATINGHARD COATINGSANODIZE & CONVERSIONPAINT & POWDERSilver plateSolder plateType II anodizePowder coatZinc plateZinc-nickelHard chromeDLCTiN PVDCadmium plateE-coatCerakoteWet paintHot-dip zincNitridingHVOF coatingTin plate — corrosion 34, hardness 0Tin plate
02550751000255075100Corrosion protection (0–100)Surface hardness (HV, log scale, 0–100)Plating — 19 finishesHard coatings — 17 finishesAnodize & conversion — 8 finishesPaint & powder — 7 finishesType II anodize — corrosion 71, hardness 54BSA anodize — corrosion 71, hardness 52Type I anodize — corrosion 71, hardness 49Hard anodize — corrosion 71, hardness 61PTFE hard anodize — corrosion 71, hardness 61Nitriding — corrosion 55, hardness 73PEO — corrosion 70, hardness 74Sherardizing — corrosion 83, hardness 56Brass plate — corrosion 35, hardness 44Bronze plate — corrosion 40, hardness 49Cadmium plate — corrosion 70, hardness 26Copper plate — corrosion 32, hardness 39Decorative chrome — corrosion 64, hardness 71Electroless copper — corrosion 20, hardness 41Electroless nickel — corrosion 70, hardness 68Nickel plate — corrosion 51, hardness 55Gold plate — corrosion 68, hardness 39Hard chrome — corrosion 40, hardness 73Hot-dip zinc — corrosion 90, hardness 42Nickel-PTFE — corrosion 72, hardness 57Silver plate — corrosion 55, hardness 39Solder plate — corrosion 42, hardness 9Zinc plate — corrosion 60, hardness 30Zinc-nickel — corrosion 86, hardness 60Cerakote — corrosion 83, hardness 27E-coat — corrosion 83, hardness 15Epoxy coat — corrosion 83, hardness 15Powder coat — corrosion 83, hardness 14Wet paint — corrosion 59, hardness 10AlCrN PVD — corrosion 58, hardness 93AlTiN PVD — corrosion 52, hardness 94CrN PVD — corrosion 62, hardness 83DLC — corrosion 55, hardness 93MoS2 PVD — corrosion 20, hardness 26TiAlN PVD — corrosion 50, hardness 93TiCN PVD — corrosion 40, hardness 92TiB2 PVD — corrosion 40, hardness 94TiN PVD — corrosion 45, hardness 87WC/C PVD — corrosion 48, hardness 77ZrN PVD — corrosion 52, hardness 90CVD alumina — corrosion 70, hardness 85CVD TiCN — corrosion 38, hardness 92CVD TiN — corrosion 45, hardness 87Multilayer CVD — corrosion 62, hardness 88HVOF coating — corrosion 78, hardness 77Plasma spray — corrosion 60, hardness 68Plastic chrome — corrosion 72, hardness 71Electroless plastic — corrosion 58, hardness 39Clear coat — corrosion 20, hardness 12Soft-touch — corrosion 20, hardness 5PLATINGHARD COATINGSANODIZE & CONVERSIONPAINT & POWDERSilver plateSolder platePowder coatZinc plateTin plate — corrosion 34, hardness 0Tin plate
Anodize & conversionPlatingPaint & powderHard coatings

Specifications for Tin plate

The documents a drawing cites to define this finish, with the Type / Class rows that apply. Each links to a page explaining the standard.

StandardType / ClassThicknessRequirement / testStatus
ASTM B545
Standard Specification for Electrodeposited Coatings of Tin · ASTM
Class A≥ 3 µmLow-resistance contacts and mild protected service. · Thickness and applicable contact tests.Active
Class B≥ 5 µmSolderability, anti-galling, stop-off, and similar mild service. · Thickness, adhesion, and solderability when specified.
Class C≥ 8 µmIndoor moderate exposure and solderability retention. · 10 µm minimum on steel. · Thickness, integrity, and solderability.
Class D≥ 15 µmDampness and moderate industrial exposure. · 20 µm minimum on steel. · Thickness, integrity, and applicable corrosion test.
Class E30–125 µmElevated temperature, abrasion, or corrosive exposure. · 30–125 µm may be required for abrasion or corrosive media. · Thickness, integrity, and specified performance.
Class F≥ 2 µmShort-term contact or limited shelf life, subject to purchaser approval. · Thickness and purchaser-approved performance.

Drawing call-out

MATTE TIN PLATE PER ASTM B545, SERVICE CLASS C, 8 µm MIN OVER 2.5 µm MIN NICKEL UNDERPLATE; PURE TIN, NO BRIGHTENERS

Pattern: TIN PLATE PER ASTM B545, CLASS <A|B|C|D|E|F>, <MATTE|BRIGHT|FLOW-BRIGHTENED>, <UNDERPLATE>

Which materials take Tin plate?

Verdict per material family, with the grades that behave differently. Each family links to its datasheets in the material library.

Material familyVerdictNotes
Brass
YesCommon electrical substrate; nickel underplate limits zinc diffusion.
Copper Alloy
YesPrimary terminal and busbar substrate.
  • Brass commonly uses a nickel or copper barrier.
Steel
With careNeeds underplate and edge-corrosion design.
Zinc Alloy
With careNeeds a strike before tin.
Aluminum
LimitedRequires specialized activation and underplating.
DMLS / SLM
LimitedMetal AM electrical parts after porosity review.
Stainless Steel
LimitedRequires activation and usually a nickel underplate.
FDM
NoFused-filament polymers are incompatible with this process.
Magnesium Alloy
NoIncompatible.
MJF
NoPolymer powder-bed prints are incompatible with this process.
Polymer
NoOrganic polymers cannot take this inorganic metal-finishing process.
SLA
NoPhotopolymer prints are incompatible with this process.
SLS
NoPolymer powder-bed prints are incompatible with this process.
Titanium
NoTitanium is not a standard tin-plate substrate.

How Tin plate is applied, and what it does to the part

  1. 1Clean
  2. 2Activate
  3. 3Underplate if required
  4. 4Tin plate
  5. 5Rinse
  6. 6Optional reflow
  7. 7Solderability and thickness test
DimensionsAllow 3–15 µm tin plus any nickel or copper underplate; threads can gall or bind because tin is soft.
Build-up per side3–15 µm — Local electrolytic buildup is heavier at edges; add underplate separately.
MaskingUsually needed. Mask contact zones requiring another finish, precision fits, and surfaces that must remain weldable.
ElectricalConductive
Temperature limit150 °C (302 °F) continuous
AppearanceMatte white-gray or bright silver-white.
Added lead time3–6 working days on top of the bare part

Design rules for Tin plate

What to decide on the drawing before the part goes to the finisher.

  1. Choose matte tin for whisker-managed designs.Bright deposits can carry higher residual stress.
  2. Specify an underplate where required.Nickel limits copper-zinc diffusion and supports solderability.
  3. State shelf-life and solderability tests.Oxide growth and intermetallics change wetting over time.
  4. Do not use tin against tin in vibration without review.Fretting and cold welding can raise contact resistance.

Tin plate versus the alternatives

Finishes engineers weigh against Tin plate, and when each wins.

FinishCorrosionHardnessCosmeticCostThicknessChoose it when
Tin plate
this page
34045$$3–15 µm—
Silver Plating
Tin plate vs Silver Plating →
553972$$$$5–20 µmwhen high-current conductivity is more important
Solder Alloy Plating
Tin plate vs Solder Alloy Plating →
42935$$5–25 µmwhen a predeposited solder alloy is required
CorrosionHardnessCosmeticLubricityEconomy
Tin plateSilver Plating

The radar overlays Tin plate with Silver Plating, its most common alternative — chosen when high-current conductivity is more important. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Tin Plating is a standard-cost finish ($$): cheaper than about 78 % of the finishes FabDigit quotes.

Finishing is priced per part with a lot minimum, from FabDigit's own China-side rates cross-checked against US job-shop pricing. The exact figure appears on the instant quote once the part is uploaded.

Lead time and compliance

Added lead time3–6 working days
RoHSCompliant
NotesPure tin is RoHS compatible; whisker risk requires product-specific controls.

What Tin plate is used for

  • Busbars
  • Terminal pins
  • Battery contacts
  • Solderable lugs

Tin plate — frequently asked

how thick is tin plating

Typical engineering tin is 3–15 µm. Solderable terminals often use 3–8 µm, while heavier service uses 8–15 µm plus any required underplate.

matte tin vs bright tin plating

Matte tin uses fewer brighteners and is generally preferred in whisker-risk controls. Bright tin looks smoother but may have higher residual stress and different solderability aging.

does tin plating grow whiskers

Pure tin can spontaneously grow conductive whiskers, especially under compressive stress. Mitigations include matte deposits, nickel underplates, annealing, design spacing, and a documented control plan.

is tin plating solderable

Yes, solderability is its main use, commonly at 3–15 µm. Storage oxidation and copper-tin intermetallic growth can reduce wetting, so shelf life and underplate matter.

tin plating vs silver plating

Tin is lower cost and readily solderable but soft and vulnerable to fretting and whiskers. Silver handles higher current with better conductivity, typically at 5–20 µm, but tarnishes in sulfur atmospheres.