tinlegering

Tinlegering, commonly known as tin plating, is a metallurgical process that deposits a thin layer of tin on a metal substrate, usually steel or copper. The tin coating improves corrosion resistance, enhances solderability, and provides a decorative, bright finish. Tin-plated steel is widely used in packaging, electronics, and hardware, with tinplate steel forming the basis of many food and beverage cans and lids.

Two main methods are used to apply tin coatings. Electroplating involves immersing clean, pretreated metal in an aqueous tin salt solution and passing electrical current to reduce tin onto the surface. Bath compositions typically rely on tin sulfate or related tin salts, and coating thicknesses range from a few micrometers to several tens of micrometers depending on the application. Hot-dip tin plating uses immersion in molten tin at approximately 230–250°C, yielding a thick, well-bonded coating with excellent corrosion protection and solderability. Substrate preparation usually includes degreasing, pickling, and fluxing to ensure adhesion; finishes may be followed by annealing or passivation.

Applications and properties. Tin coatings are valued for their resistance to corrosion in many environments, good solderability, and the ability to form adherent, uniform surfaces on steel and copper parts. In packaging, tinplate steel is used for cans, closures, and related hardware. In electronics and electrical components, tin coatings aid soldering and provide a protective layer. Tin can form an oxide that limits further corrosion, but tin whisker growth is a consideration in some high-reliability applications.

Standards and limitations. Tin plating is governed by industry standards such as ASTM B545. Limitations include wear resistance compared to harder coatings and environmental considerations related to processes and finished products.