This process can reduce wasted labor and materials on flawed pieces. Though creating the proper temperature and cooling conditions for molten metal will reduce the risk of metal dendrite formation, it’s still essential for manufacturers to test cooled metal workpieces for metal dendrites. For example, dendrites can change the weldability of the cooled metal and impact the welding method used. Much like tin whiskers, metal dendrites play a role in the metal’s conductivity by altering its chemical, electrical, and mechanical properties. As such, metal fabricators must find the ideal cooling conditions for each metal and alloy they work with, so the finished products have minimal dendrite formation risk. The temperature of the environment the metal rests in as it cools, and the resulting rate of cooling will determine the level of dendrite formation. These metal dendrites typically appear as molten metal starts to cool and harden. They develop along a surface two-dimensionally rather than growing. They have a tree-like (dendrite-like) structure of crystalline branches that spread throughout the affected metal. Metal dendrites have a different shape than tin whiskers. Metal Dendrites: What are They and How Do They Form? Minimize mechanical and physical stress during handling and assembly, as well as during use in the field.Consider replating areas of a component or product that are particularly likely to develop tin whiskers.Ensure that tin-plated parts are sufficiently solder-dipped in tin-lead solder.When possible, use a tin-lead alloy or another alloy instead of pure tin or zinc.These strategies may help to reduce the risk of tin whisker formation: ![]() The dissolution of the metal before plating does not affect the likelihood of formation. For example, tin whiskers can form whether or not there is an electromagnetic field present. Investigations have identified factors that may increase the formation of twin whiskers and elements that do not impact formation. Documented issues scale in severity from short circuits up to complete electronic system failure. This variable conductivity can be problematic, especially in devices with numerous closely placed circuits. This varying conductivity increases the risk of electricity traveling from one circuit to another with differing electrical potential, thereby short-circuiting the entire component. The crystalline structure of tin whiskers makes them more conductive than the surrounding tin or other metal materials. ![]() Manufacturers and inspectors primarily find tin whiskers in tin plating, especially during the final finish of a manufactured component or after electroplating. The structures can grow to several millimeters long but rarely extend beyond 10 mm. Tin Whiskers: What are They and How Do They Form?Īt their core, tin whiskers are crystalline structural formations that can occur in pure tin and other pure metals like zinc, cadmium, and silver. ![]() The ability to recognize metal dendrites and tin whiskers is critical during testing and inspection processes. metal dendrites, technicians must understand the phenomenon and the best practices for mitigating tin whisker formation. The two seem similar to the untrained eye, making it difficult to tell the difference between the two structural defects. While metal dendrites have been a long-identified metal fabrication problem, the discovery of tin whiskers came more recently. Tin whiskers and metal dendrites are structural formations that appear in tin materials during manufacturing and finishing processes.
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