Tin Plating

Tin plating is a highly valued metal finish due to its unique set of properties.  Tin has been utilized in some capacity by humans for over 5000 years.  At the start of the Bronze Age, tin alloys (1-10% tin) were used to make bronze for weapons and shields dating to around 3000 B.C.  Later, tin was isolated in a more pure forms, leading to the discovery of pewter (85-99% tin).  Pewter flatware remained in use from ancient times up until the 20th century.  Today, tin in the form of tin plate, is used as a food-safe metal finish along with being a useful industrial material with far-stretching applications.

Originally tin coatings were produced by hot-dipping parts in a liquified tin solution.  However, as a result of stringent regulation on its use during WWII the vast majority of tin plating has migrated from hot-dipping methods to electroplating methods, the latter of which uses considerably less of the raw material during processing.  Although wartime restrictions no longer apply, modern tin electroplating baths produce higher quality tin finishes at a cheaper cost than their hot-dipping counterparts, all but eliminating the need for hot-dip processes.

A Square plates ROHS compliant tin utilizing an bright acid tin bath.  This bath is capable of providing bright or semi-bright tin coatings from several micro inches up to thousandths of an inch.  Our tin plating finds use in a number of industries including: food service, fittings and connectors, electrical production and distribution, naval,  bus bar, medical, aerospace and etc. We are committed to working with our customers to provide a tin finish that satisfies any specifications callout: including reflowed and hot tin-dipped.  Please contact us regarding all of your tin-plating needs.

BENEFITS OF TIN PLATING

  • Resistant to corrosion and tarnish
  • Non-toxic and safe for food contact 
  • Extremely ductile
  • Excellent lubricity
  • Solderable
  • Decorative bright finish
  • Soft and malleable
  • Good thermal conductivity 
  • Good electrical conductivity

DRAWBACKS OF TIN PLATING

Tin is a semi-precious metal.  As a result, it demonstrates phenomenal material properties. However, depending on the specifics of the project there could be potential drawbacks when utilizing this metal finish:

  • Tin-Whiskering: Tin metal has the tendency to form tiny filiform tin 'whiskers' which extend from the basis metal.  In some circumstances the whiskers can become problematic, for example short circuiting a electrical circuit.  Alloying tin plating with lead will mitigate the whisking phenomenon.   However, the coating will no longer be ROHS compliant.  Another solution is to "reflow" the tin after plating. However, due to the dangerous and costly nature of this process we do not perform this service at A Square.  That said, we have never been contacted by a customer regarding the whispering of our plated tin.
  • Low melting point: Tin melts at 232°C (450°F) and begins to flow several degrees below this point.  Thus, the metal is unsuitable for high-temperature applications.

TIn FINISHES

Tin plating is available at A Square in bright and semi-bright finishes via a bright acid tin bath.

  • Bright
  • Semi-Bright

PLATING SPECIFICATIONS

  • ASTM B-545
  • MIL-T-10727
  • AMS 2408
  • Customer directed specifications

In general, we plate our tin to industry standard specifications (ASTM B-545 or MIL-T-10727).  However, we have the capability to adapt our processes to suit any given customers engineering requisites or specifications.  Please contact us to engineer a customized solution to fit your part performance requirements and tin plating needs.

PLATING METHODS

  • Rack Plating
  • Barrel Plating
  • Selective Plating

PROPERTIES OF TIN

  • Appearance: White lustrous metal
  • Conductivity (Thermal): 67 W/(m·K)
  • Resistivity (Electrical): 115 nΩ·m
  • Density: 7.37 g/cm3  (.266 lb/in3 )
  • Melting Point: 232 °C ​(450 °F)
  • Atomic Weight: 187.7 g/mol