tinning

Tinning is the process of applying a thin layer of tin to another metal surface. The tin coating provides corrosion resistance, improves solderability, and can act as a barrier to diffusion between metals. When used for food-contact surfaces, tin offers a stable, non-toxic layer, as in tinplate products and tin-lined cookware.

Tin can be applied by several methods. Hot-dip tinning submerges the cleaned metal into molten tin to form a uniform coat, a common method for producing tinplate steel and for coating various parts. Electroplating deposits tin from tin-containing electrolytes through an electric current, allowing precise control of coating thickness. Mechanical or brush tinning uses physical deposition for specific applications. The resulting coatings are typically measured in micrometers.

Common applications include tinplate steel used for food and beverage cans, tin-lined copper cookware, and tin-coated wires and hardware to prevent corrosion and improve solderability. In electronics, tin or tin-based finishes are used to enhance solder wetting and protect surfaces from oxidation; solder itself often contains tin, and tin whiskers can be a consideration in some devices.

History and related terms. Tinning has long been used to protect and prepare metal surfaces, with tinplate becoming central to the modern metal can industry in the 19th century. The term also appears in the practice of tinning soldering irons, where a layer of solder coats the iron tip to improve heat transfer and resist oxidation.

Safety and maintenance. Tin coatings can wear over time and may require reapplication for continuing protection. Tin is relatively non-toxic in many consumer applications, though industrial processes should follow appropriate handling and disposal guidelines.