GLENAIR
These alternatives are still being tested and evaluated for their long-term performance, and further research and development may be required before they can fully replace cadmium in finish plating applications. You did not mention Tin-Zinc. Has this material gained inroads in US military specifications? Yes, tin-zinc is another alternative material that has gained traction as a replacement for cadmium in finish plating. It has been adopted by several US military specifications as a replacement for cadmium, due to its good corrosion resistance and compatibility with various base metals. Tin-zinc coatings can be deposited on various metal surfaces, including steel, aluminum, and magnesium, and can offer a viable solution for applications where high corrosion resistance, solderability and conductivity are required. Overall, tin-zinc is considered to be a promising alternative to cadmium, and its use is expected to continue to grow in the aerospace and military industries, as well as other industries where high- performance coatings are required. Is Tin-zinc a sacrificial or barrier type of surface finish? Tin-zinc plating is a sacrificial type of surface finish. In other words, it is a coating that corrodes preferentially to the substrate, thereby protecting the substrate from corrosion. Tin-zinc plating works by corroding in a controlled manner, forming a protective layer of zinc oxide and tin oxide on the surface of the coating. This protective layer acts as a barrier to prevent further corrosion of the substrate, making tin-zinc an effective solution for improving corrosion resistance in harsh environments.
In comparison, barrier type finishes, such as anodizing or electroless nickel, work by forming a dense, impermeable layer on the surface of the substrate that acts as a barrier to prevent corrosion. These finishes do not corrode preferentially to the substrate, and therefore do not provide ongoing protection in the same way that a sacrificial finish does.
We understand NAVSEA has qualified Tin-Zinc for use in M28840 series connectors. Do you
have any information on this development?
Yes, the US Navy’s Naval Sea Systems Command (NAVSEA) has indeed qualified tin- zinc for use in M28840 series connectors. This development is significant, as it demonstrates the confidence of the military in tin-zinc as a replacement for cadmium in high-performance applications. The qualification of tin-zinc for use in M28840 series connectors by NAVSEA indicates that the material has been thoroughly tested and meets the rigorous performance requirements of military specifications. This will likely result in increased adoption of tin-zinc in other military and aerospace applications where high-performance coatings are required. Tin-zinc is considered to be a viable alternative to cadmium due to its good corrosion resistance and compatibility with various base metals. The qualification of tin-zinc by NAVSEA for use in M28840 series connectors confirms that it can provide the performance and durability required in high-stress military and aerospace applications.
Has the MIL-DTL-38999 connector specification also qualified Tin-Zinc as a
suitable finish plating?
Yes, the MIL-DTL-38999 connector specification has also qualified tin-zinc as a suitable finish plating material, although the final release of the new specification listing Tin-Zinc has not yet been released. The MIL-DTL-38999 specification is a military standard for circular electrical connectors, and its qualification of tin-zinc as a finish plating material demonstrates its suitability for use in high-performance military applications. The use of tin-zinc in MIL-DTL-38999 connectors provides several benefits, including good corrosion resistance, compatibility with other plating types, and improved solderability. Tin-zinc is considered to be a cost-effective alternative to cadmium, and its
QwikConnect • April 2023
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