TIN-Bismuth ON STAINLESS STEEL. BRILLIANT

Characteristics

Advantages of tin plating:

• Tin coating with a nickel underlayer increases the corrosion resistance of stainless steel products in a saline environment.
• The tin coating prevents direct contact between stainless steel and aluminum and copper. As a result of such direct contact, it is possible to form a galvanic couple in which stainless steel will act as the cathode and aluminum as the anode, i.e. active corrosion of aluminum will occur. Contact with copper may accelerate corrosion of the steel itself.
• Resistant to sulfur-containing compounds and recommended for parts in contact with all types of plastics and rubbers. Tin is also stable in saline environments.
• Provides solderability of stainless steel. A shiny tin-bismuth coating retains solderability for a longer time than a matte finish. Alloying with bismuth allows you to maintain solderability for more than a year.
• Has good anti-friction properties.
• Doping with bismuth prevents the formation of conductive needle crystals on the coating surface during storage.
• Doping tin with bismuth in an amount of more than 0.5% also avoids destruction of the coating at temperatures below -30°C. The destruction of tin coatings WITHOUT bismuth occurs due to the transition of compact white tin β-Sn into powdery gray α-Sn (the “tin plague” phenomenon).

Disadvantages of tin plating:

• Low wear resistance when rubbing against harder materials and under abrasive influence.
• Lower antifriction properties compared to tin-lead and lead.
• The presence of bismuth in the composition does not allow the use of coated products if they must come into contact with food environments.
• Relatively unstable in an alkaline environment (gradual mild corrosion).